SY]

Describe function of the given component in PCS/GSM architecture.

Classify the given GSM logical channel,
mm

Describe the given step of call processing in GSM.

Explain the significance of given type of area in cellular network.
'

g Objectives...
f=) To understand Basic Concept of Wireless and Mobile Networks
@) To learn Basic Concepts of PCS and GSM
{™) To study Typical PCS and GSM Network Architecture
{®) To learn Handoff and Roaming
{®) To understand Concept of Mobility Management and Network Signaling

INTRODUCTION
Wireless and mobile communication networks have tremendous success in today’s communication
market both in general or professional usage.
Wireless refers to a communications, monitoring or control system in which electromagnetic waves
carry a signal through atmospheric space rather than along a wire.
The evolution of radio and mobile core network technologies over the last two decades has enabled
the development of the ubiquitous Personal Communication Services (PCS).
A PCS can provide the mobile user with voice, data and multimedia services at any time, any place
and in any format. The ultimate goal is to provide a PCS, which will move information of all kinds te
and from people in all locations, through an advanced wireless network supporting a wide range of
Services. RAS AN
'SM stands for Global System for Mobile Communication \\t isa
i clgitsl cellular technology used for
anismitting mobile voice an
and data services. — at
———_——

GSM Communication is a wireless communication system that uses digital cellular radio,
communication to provide “voice, data and “multifiiedia | applications ~cOmmunication services.
It
coversWide aréa ofrange of mobility.
A GSM system co-ordinates the communication between mobile telephone units (mobile stations),
base stations system (cell cites) and switching systems (MSC or MTSO),—____
rhe bandwidth of each GSM radio channel is 200 KHz wide and which are fi
ames that hold and rime slots. GSM was original named as (Groupes pe
The Personal Communication Service (PCS) is a high frequency, low‘power, §
mobile communication system, It mainly operates within the rangeoh\. 1800 to1900 MHz.
Sa —

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 Wireless and Mobile Networ
k
1.2
* The principle technology base fort
: he PCS comes from snular, the ¢©
ee well-established digital wireless cellular systems, wirel ess analog cellu lar, The
It has also evolved from ees
or Mobile Communications (GSM) networks. |
onal comp:
* The implementation of the PCS is based on the interconnection of various a and reliability ¢
that are operating in accordance with developed standards so that interoper@ v |]
the systems can be achieved. hone tech
© Personal Communications Services (PCS) is a new generation of Eek: and dig
introduces a range of features and services surpassing those available in ane
phone systems.

P AL COMMUNICATION SERVICES time, a

(PCS)__—--
F.
e objective of PCS is to enable communication with a pero Tee aervice py providing unlimited
ding tot
form. It. also manages their individual call services accor
-Teachability and accessibility.
. The key factors of PCS are gi iven below: ce, in public, in transit).
{lity with respect to Location (Home, offi
2a oa to Device (Cellular phone, wired phone, fax etc.).
t of Service.
scant commatRRGRTIORS service (Pcs) refers to a wide
. peiea variety of wireless acces s and Sa
with the goal
al, of enabl ing comm unica
mobility services provided through a small termin
any time, at.any place and in any form.
PCS:
of es
Featur
* The salient features that enable PCS to provide communications with anyone, anywhere, anytime

" X honing A057 The roaming service should be greatly expanded to provide universal
y's
__ 2 Diverse Environment: Users must be able to use the PCS in all types of environment. For example,
commercial, residential, mountains and recreational areas.
__& Wariots ‘Bize: With PCS, there will be a mix of broad types of cell sizes. The picocell for low
applications, the microcell for lower-power outdoor pedestri
Fai ta
Strian
z application. The
rs vehicular applications and super macro
cell with ati :
1,PCS provides a low pow = — -
» elephone Network (PSTN),
The user should be via access Connection to the Publi¢
. if _ having to recharge
its battery. try the handset outside without
5. FCC Frequency locatioi The
Allocation, FCC frequene ¥ allocation f or ot oad
20 PCS usa
f Seen ove another 20 MHz
a oe for untcenee? oneal
pie is three times the spectrum currently allocated
Advantages
of PCS:
© PCS offe
a numb
rs er of advantages over traditional cellular
communieati
htweight Phones Cations:
s be tailored to each j with advanced
customer, features such as paging
em acre
; goyama:- and owe doppd ae
nly Integrated Voice and «....°

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 Wireless ang Mobile Network He Basics of PCS and GSM
Gos

ersonal Communications Services (PCS) refers to a wide variety of wireless access and personal
mobility services provided through a small terminal, with the goal of enabling communications at
any time, at any place and in any form.
* Business opportunities for such services are tremendous since every person (not just every home) 2
could be equipped as long as the service is fairly inexpensive. ass
“i Meet of them are connected to the public switched telephone network(PSTN) to provide access to
land line telephones. =
= PCS technologies have grown rapidly in the telecommunications industry. Two of the most popular
ee High-Tier Cellular telephony, Cordless and low-Tier PCS telephony.
* These techMologies have similar architectures,as shown inFig.1.1. S eS
oy vf = i oe
c.

5 £
—_ — t

_ a
—
, .
Os) se | = 7

=~ OH i
Sue“<3 |
‘ 3
- - BTS -
2 BTS|-P{BSGH
nN = well | [ers = wre
aoe i / | —

— | E PSTN ey z
Dd

) [sin Abis interface [Msc]}—[EmsC SSP \ : —

: \ = ~ %
'
co
x MS BTS : (Se rs all a

BTS BSC ame ace iSS7/ fle

a S BTS | Network and switching oD te
~ Uminterface ; subsyhstem(NSS) ~~ \
Base station = -
am ~ ; Se
subsystem (BSS)
Fig. 1.1; PCS Architecture Noy, yy =
; ee
e Basic architecture consists of two parts:
oo
1. Radio Network,
2. ireline Transport Network >
i, o Network:
Cc

PCS use Mobile Stations (MSs) to communicate with the Base Stations (BSs) in a PCS network. MS is
Wa pty

also referred to as handset, mobile phone, subscriber unit or portable unit.

* Modern MS technology allows the air interface to be updated (eg from DECT to GSM) over the air
remotely. The MS can also be remotely monitored by the system maintenance and diagnostic
capabilities.
« Different types of MSs have various power ranges and radio coverage. Hand-held MSs have a lower
output power (where the maximum output power can be as low as_0.8 watts for GSM 900) and
shorter range compared with vehicle-installed MSs with roof-mounted antennas (where the
maximum output power can be as high as 8 watts in GSM 900)
© in the base station is called a cell,For systems such as
The radio coverage of a base station or asector
GSM,CDMA and PACS the base station system is partitioned in to a controller (base station controller
in GSM and radio port control unit in PACS) and radio transmitters/receivers (base transceiver
stations in GSM and radio ports in PACS)

ee i.

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 Wireless and Mobile Network 14

Example:
Subscriber unit: Wireless local loop. |
\ FORIDIE:Tow-tier systems ACS). “i
Mobile Station: GSM system, .
Wireline Transport Network: via la
etwork (core OF backbone network)
The base stations usually reach the wireline transport 7 tailo 8 pecial switch
links or dedicated microwave links. is 4
connected to the base station
The Mobile Switching Center(MSC)
mobile applications. c is conn
The
AXE switching platform.users.
The Ericsson MSC is based on csits users and the wi line TRE”
provide services between the\P
the locations of mobile stations.
mobility databases to track ; —
:
ple: =a
es ‘os nae 2
MSC modified from Lucent Technonologi EW &
The Lucent SESS MSC 2000 is an platf orm is based its
D900/1800/1900 GSM switch
The Siemens
Switching System) platform.

GSM NETWORK AR
CHITECTURE te chnology used fory

)
di gi ta l ce ll ul ar
Communicatio—— n. I tis a
sta nds for Glo bal Sys tem for Mobile .
GSM ———
7 e ee

ce and data services. to for..: th

transmitting mobile voi all interact together
a
—_—_
——_— =

fer ent ele me nts tha t

hitecture consists of dif controller, MSC, Auc,
HER, VLR, etcy
* The GSM network arc like the bas e-s tat ion ,
include elements
overall GSM system. These
k
the dif fer ent ele men ts wi thin the GSM networ
cifications define
» The GSM technical spe ch they inte ract to enable the
def ine s the dif fer ent ele ments an d the ways in whi
architecture. It
maintained.
overall system operation to be other later cellular systems now
net wor k arc hit ect ure is now we. ll established and with the
The GSM
new ones being deployed, the bas
ic GSM network architecture has been
established and other
k elements required by these systems.
updated to interface t 0 the networ
architecture has been
tems, the basic GSM system
Despite the develop ments of the newer sys
the same functions as they did
maintained, and the network elements described below perform element.
nc hed in the early 1990s/GSM network architecture
when thaoriginal GSM system was lau
uped into four main —<a
The GSM network architecture as defined in the GSM specifications can be gro
areas:
1. Mobile Station (MS).
2, Base-Station Subsystem (BSS). ~~
3, Network and Switching Subsystem (NSS),
4, Operation and Support Subsystem (OSS), — =
The different elements of the GSM network o perate together and the u ser isi not aware of the
different entities within the system.
A basic diagram of the overall GSM system architecture with these four major or ele
el ments is shown
below:
Mobile Station:
(ME) or as they are most widel ,
Mobile Stations (MS), Mobile Equipment
y Xnown, , cell or mob il
mobile phones _
are the section of a GSM cellular network that the user Sees and operat, es,

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 Wireless and Moblle Network 15’ Basics of PCS and GSM

* In recent years their size has fallen dramatically while the level of functionality has greatly
increased, A further advantage is that the time between charges has significantly increased.
* A further advantage is that the time between charges has significantly HACTEASEG: There
are a
number of elements to the cell phone, although the two main elements are the main hardware and
the SIM.
* The hardware itself contains the main elements of the mobile phone including the display,
case,
battery, and the electronics used to generate the signal, and process the
data receiver and to be
transmitted] it algo contains a mimber known as the International Mobile Equipment
Identity (IMEI).
* This is installed iii the phone at manufacture and "cannot" be chan
It isged.
accessed by the
network
——
during registration to check whether the equipment has been
reported as stolen.
* The SIM or Subscriber Identity Module contains the information
that provides the identity of the
user to the network.
It contains are variety
fntemnational Mobile Subscriber Identity (IMsiy7of information including a number known as the
2, Kase Station Subsystem (BSS);
~* The Base Station Subsystem (BSS) section of the GSM
network architecture that is fundamentally
associated with communicating with the mobil
es on the network.
* Itconsists of two elements:
Zs Base Transceiver Station (BTS):
° The BTS used in a GSM network comp
rises the radio transmitter receiver
antennas that transmit and receive to s, and their associated
directly communicate with the mobiles.
* The BTS is the defining element for
each cell. T he BTS communicates
‘ interface between the two is known as with the mobiles and the
the Um inte Tface with its associated prot
ocols.
Base Station Controller (BSC):
* The BSC forms the next Stage back into the G
SM network. It controls a group
located with one of the BTSs in its group. of BTSs, and is often co-
Coit es the radio resources and controls items su

-
Zee Switching Subsystem (NSS);
* The GSM system architecture con
tains a variety of different ele
network, ments, and is often termed
the core
* It provides the main con
trol and interfacing for
within the core network inc the whole mobile networ
lude: k, The major elements
(i) Mobile Services Switching Ce
ntre (MSC):

mobil su istration, authenticati

ee eel e ion,
eation, Tre ASC handand
i
* It also provides an in erface to the PSTN so that calls ¢ ovallerroutsing toa
an be routed from the
. mobile
network to a
On different ne €. Interfaces to other MSCs are pro
tworks. vided to enable calls to be mad
e to

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 Wi
Tet nd Mobi Nore

1.6
(ii) Home Locati
on Register (HLR);
This database contai
tain : og
information about each subscriber te
known location, In 5 all the administrative
MS. way, the GSM network is able to route calls to the ee , ON
and from this
* Wh
: = user switches on their phone, the phone registers with the Las :
that ine? rep
to determine which BTS it communicates with 80
appropriately. Even when the phone is not active (but switched =
ri ou s gu b-centers t0 for
ross V4
ensure that the network (HLR) is aware of its latest position.
tributed
twork, although it may be dis
There is one HLR per ne
® idu al
operational reasons, f o r t he indiv
R):
ate d
cte services
Re gi st er (VL
(iii) Visitor Location from the HL R tha t ena ble s thes
part of
ai ns sel ect ed information 7 sed 4 an |integral
° This co nt t.
to be pr ov id ed . is co mm on ly
fas “ more C onvenien
subscriber , but" it ad e
im pl em en t ed as a separate entity is
The VLR can be enti ty. In this
way access
dge of
without any knowle
*
tha n a sep ara te
the MSC, rather y ro ut ed :
(GMSC):
Switching Centre initial awh
(iv) Gatewa y Mo bi le
ME te rm in ating call is Nu mber) from the
HLR
e po in t to wh ic h a Sio n go am in g
¢ The GMSC is th d
aoFE “asyan routing the
the MS's location.
ob
N (M(MoD!
SRRN il or y y
in ch ar ge of obtaining the/MS ia a = : re
thus
« The GMSC is e Station ISDN
umber the
y
based on the
MS IS DN (M ob il
. i. op er at io n do es not require an
y op e
t visited MSC. ding, since th
e gatewa
call to the correc SC is mi sl ea
of the term GM
e The "MSC" part
C. ;
linking to an MS age —
wa y (S MS -G ): ti ve ly de sc r! be the two Short Mess
(v) SMS Ga te used to coll ec
or SM S ga te wa y is the term that is ga te wa ys ha n dle messages directed in
* The SMS-G rds. The two
Ga te wa ys de fi ne d in the GSM standa
services
different directions
.
y Mo bi le Sw i tch ing Cen tre) is for short messages
tewa
rt Message Service Ga Switching
» The SMS-GMSC (Sho
s- IW MS C (S ho rt Me ss ag e Service Inter -Working Mobile
being sent to an ME. The sM ate d wit h a mob ile on that S- network. provides a siyed acti 1
es ori gin MSC
Centre) is used for short mes to that of the GMSC, whereas the SM IW
sag
is sim ila r
+ The SMS-GMSC role
Centre.
point to the Short Message Service
can also connect to public dat
(vi) IWF: Using Additional Interworking Function, MSC atnneiwers :
(OSS):
4, Operation and Support Subsystem
« « The OSS or operation support sub system i
is an elem esas

arch it
that ec
is connec tedtu re
to compon ents of the NSS and e aBSC. the overall (Gea
e It is used to control and monitor th
load of the BSS. © overall GSM network and it is also useded to control the traffic

(i) Equipment Identity Register (EIR):

d
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e
 _ Wirel
and Mobile
ess Network 47 _Basica of PCS and GSM. |
¢ ach mobile equipment has a number known as the International Mobile Equipment Identity. This
number, as mentioned above, is installed in the equipment and is checked by the network during
registration.
* Dependent upon the information held in the EIR, the mobile may be allocated one of three states -
allowed onto the network, barred access, or monitored in case its problems. |
(ii) Authentication Centre (AuC):
e The AuC isa protected database that contains the secret key also contained in the user's SIM card.
* “Itisused for authentication and for ciphering on the radio channel.
(iii) Operational Subsystem (OMC): _
* Monitors and maintains the performance of all other entities such as MS, BS, and BSCIOMC
is>
Responsible for traffic monitoring, subscriber and security management, Accounting and Billing.
GSMNetworkinterfacess =|“
= =
_-~ The different interfaces used to provide communication between various elements in a GSM cell
phone network The network structure is defined within the GSM standards.
* Additionally each interface between the different elements of the GSM network is also defined. This
facilitates the information interchanges can take place.
* Italso enables to a large degree that network elements from different manufacturers can be used.
However as many of these interfaces were not fully defined until after many networks had been
deployed, the level of standardization may not be quite as high as many people might like.
i. ) Um Interface: The “air” or radio interface standard that is used for exchanges between a mobile
(ME) and base station (BTS / BSC). For signalling, a modified version of the ISDN LAPD, known as
|
LAPDm is used. _ AM
2., Abis Interface: This is a BSS internal interface linking the BSC anc.s BTS,
$d it has not been
totally standardised. The Abis interface allows control-of the radio eqlipment and radio
frequency allocation in BTS. ae r oe
4 A Interface: The A interface is used to provide communication
between th BSS and the MSC.
Interface carries information to enable the channels,
timeslots and the like to be allocated to the
mobile equipments being serviced by the BSSs. The messaging required
within the network to
enable handover etc to be undertaken is carried over the\interface.
4. B Interface: The B interface exists between the a and the VLR .\It uses protocol known as the
MAP/B protocol. As most VLRs are collocated
With an
MSC, this makes interface purely an
“internal” interface, The interface is used
whenever the MSC needs access to data
located in its area, regarding a MS
Cc
5. C Interface: The C interface is located
between on HL and a GMSC ora SMS-G\
S eses f, ii outside network, |e, from
originat , ; When a call
PSTN or arlother mobile; network itahs es
gateway so that routing information required to pass through
to complete the call may be
used for communication js MAP/C, gained, The protocol
the letter "Cc" indicating that th
interface, In additi fla Mat, , tee
'€ protocol is used for the "cr"C
errata ted andto this, MSC may
the call is comple optionally forward billing information to the HLR after
cleared down. CS)
6. D Interface: The D int
erface js situated betw
excha
nge data related to the location of th een
ba LR and HLR\ It /D 1
e ME and to the man uses é subscr
AP (Dil piptacelty
7. E Interface: The E inter \nagement of thé subscriber,
exchanges data related pec
_ here oh besp
protocol. er Detween the anchor and e, re i y MSCecenaing the tare
s using the MAP/E —_——

OA RLS
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 | Mobile Network
i
terface: The F interface
is used between ai MSC and EIR,
communications along this interface are used to Co
access to the network, ikea ee
9. G Interface; The G interface interconnects two VLRs of different Mscs|and uses the
Protocol to transfer subscriber information, during @&- | eprocedure,
10. H Interface: The H interface exists between the MSC the SMS-G, It transfers short messages.
uses the MAP/H protocol. Bre igh t
11, Interface: The | interface can be found between the MSC and the ME. Messages exchanged
g,
the l interface are relayed transparently through the ss

}
if

NSS ed 1 i as Si

é
set ,’ [GMSGM—'SDN, PSTN
i i! ¢ -" PDN
{ wr -t--a ‘i ee ite

Fig. 1.2:GsmM Archit

ecture
GSM Frequency Spectr
um
or Cellular communicatio
n only narrow b andwidth
i j
Pen for GSM is listed below: sb ae
GSM 900; VM oe
MILstatTV
ed. The equencies a
A0CC
icles and spe
Uplink: 890 MHz to 915 MHz, ——~
E40 -G (gm
i
| Downlink: 3 935 to 960MHz, Se ; 1 4]
Awl) s WS W900 ( é
AST -SCGM
Absolute Radio Frequency Channels (ARFCN)-124
—~—
EGSM 900: mts
Uplink: 880 MHz to 915 MHz.
Downlink; 925 MHz to 960 MHz.
Absolute Radio Frequency Channels (ARFCN)-174,
GSM 1800(DCs 1800):
Uplink: 1710 MHz to 1795 MHz,

te as |

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% and le Network 1.9 Basics of PCS and:

|
Downlink: 1805 MHz to 1880 MHz, ee
Absolute Radio Frequency Channels (ARFCN)-374.
Pcs 1900; seh eS
Uplink: 1850 MHz to 1910 MHz. ~<
Downlink: 1930 MHz to 1990 MHz. > Q a
Absolute Radio Frequency Channels (ARFCN)-299. Ss ~
{ fe

Radio Aspects of GSM

In GSM uplink (mobile to base) frequency band is SYOHeI MHz, ’resulting in 45 MHz spacing for
duplex operation. aoe a

eGSM uses TDMA andF FDMA whereby the available 25 MHz spectrum is partitioned in to 124
iers (carrier spacing=200 KHz) and each carrier in turn is divided in to 8 time slots(radio
channels). —[S=__
e Each user transmits periodically in every eighth time slot in the uplink radio carrier and receives
in
a corresponding time slot on the down link carrier.
* The several conversations can take place simultaneously at the same pair of transmit/receive radio
frequencies. The radio parameters for GSM are summarized in Table 1.1,
Table 1,1
Sr. No. Parameter Specification —
1. Reverse channel frequency 890-915MHZ
2. Forward channel frequency 935-960MHZ
EF ARFCN Number 0 to 124 and 975 to1023
4. Tx/Rx frequency spacing 45 MHZ
5. Tx/Rx Time slot spacing 3 Time slot
6. Modulation data rate 270.833333kbps
tk Frame period 4,615ms
8. User per frame 8 > y
9. Time slot period 576.9microsecond Coys
10. Bit period 3.692microsecond = ——— S
11, Modulation 0.3GMSK
12. ARFCN channel spacing 200 kHz
13. Interleaving 40ms
| _ 14. Voice coder bit rate 13.4kbps

2) GSM Services
. ;
GC SM provides hale) services for "es and data. There are three ypes of services delivered by a
GSM system as, Teleservices, Bearer (or data) services and Suppleme
ritary ISDN services.
They also include subservices, The various services offered by aa GSM system are as under:
1. Telephone Services:
Standard mobile telephone, Mobile-originated
* Base-originated traffic, emergency
calling
* Fax, Videotext |

E rrr .
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 wireless and Mob!

2. Tele text, SMS, MMS (Supplementary Services):

. Supplementary ISDN services:
I
* Call diversion, Caller line ID
————_—_—_———. .
* Closed user group, Call barring
* _Call waiting, Callhold
* Connected line ID
3. Multiparty (Teleconferencing):
* Call charge advice
allow GSM subscriber and Bg »,
This service also include the Short Messag
ing Service (SMS) ha
transmit alphanumeric pages of limited length (160 -7-7 ASCH
ASCII Chara char acters) while simultaneg,.)
carrying normal voice traffic. ——
GSM Channel Types
GSM cellular communication, logical channels are a portion
i of a physical
ical channel that is Used for
@ particular (logical) communication purpose.
ide for these all
The physical channel may be divided in time frequency or digital coding to provide for these log
channels,
* Classification of GSM logical channels and functi of
on each channel:
1. GSM traffic channel (TCH):
may be either full rate or half rate and may
carry either digitized speech or user data,
\ Full Rate TCH:
* Full rate speech channel (TCH/FS): This
channel carries user speech which is dig
ee rate if 13kbps. With GSM channel itized at a raw data
coding added to the digitized spee
ch,
_-©. Full rate data channel for 960
0 bps(TCH/F9.6): This channel
© 9600 bps. With additional forward carries raw user data which
is sentat
erro r correction coding applied by
data is sent at 22.8kbps. GSM standard the 9600bps
j* Full Rate Data Channel for 4800bps(
TCH/F4,8): This channel carries
4800 bps. With additional forw raw user data which is sent at
ard error correction coding
data is sent at 22.8kbps. applied by GSM standard the
4800bps
(4 *, Full Rate Data Channel for
2400bps (TCH/F2.4): This
channel carries Taw user
data which is sentat
data is sent at 22.8kbps.
Half Rate TCH:
* Half Rate Speech Channel
(TCH/HS): This channel has
© which is sampled at half rate of ‘Skbps. with GSM ch een desi Rae
half rate speech channel wil] car 6.5 enannel coding “siadgne d to carry digi
ded ¢ the digit tized speech
ry data at 11.4kbps,
Half Rate © the digitized speech ththe
e”
)
S 4800 bps. Dat a Channel for 4800bps (TC
With additiona l forward error H/H 4 8):
correctionThi ect . .
nnel carries ray USer data which
3 cha .

, data at 11.4kbps. is sent at |

‘NB applied by GSM, this channel will

OQ Half Rate Data Channel carty
for 2400bps (TCH/H2.4)
‘This cha
data at 11.4kbps.

oo
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 se> ‘\
<
\8 oO a
0 TT on: aa iii Baofsi
PCS cs
and GSM x
A pear
. GSM Control Channel (CCH =
a
tn cate link layer is formatted for the data burst bits. The 184-bits are added
after 40 party bits, four bits and 224 hold convolution coding bits to result in the 456-bit packet. no) |
« There are three main types of control channels in the GSM system. They are: (1) Broadcas
t channel
(2) Common control channel (3)Dedicated control channel,
\ Broadcast Channel (BCH):
e Broadcast Control Channel (BCCH):The BCCH is a forward control channe
l that is used to broadcast
@ ; ation such as cell and network identity, operating characteristics of the
cell (current control
channel structure, channel availability and congestion). The BCCH also
broadcast a list of channels
that are currently in use within the cell.
@ * Frequency Correction Channel (FCCH): The FCCH allows
each subscriber unit to synchronize its
internal frequency standard (local oscillator) to the exact freque
ncy of the base station.
ey Synchronization Channel (SCH): SCH is used to identify
the serving BS while allowing each mobile
to frame synchronizes with the BS. The Frame Numbe
r (FN) is sent with the base station identity
code (BSIC) during the SCH burst,
on Control Channel (CCCH);
Paging Channel (PCH): The PCH provides paging
signals from the BS to all mobiles in the cell, and
tifies a specific mobile of-an ‘incoming call whic
h originates from PSTN, PCH may be used to
provide cell broadcast ASCII text messages to all subscriber
s.
Cy
LD) * Random Acceeess Channel (RACH): The RACH
: is a reverse link channel used by a subscrib
er unit
acknowledge & —— to
page——
from the PCH r
and ise
also m
used by mobiles to originate a call.
ae
Access Grant Channel (AGCH): The AGCH is used by
Ley

the BS to provide forward link communicatio

to the mobile, and carries data
n
which instructs the mobile to operate in a particular physical
channel.
Oy sae Control Channel (DCCH):
} Stand-alone Dedicated Control Channel
(SDCCH): The SDCCH carries signaling
>qo connection if the mobile with the data following the
BS, and just before TCH assignment issu
ed by the BS. The SDCCH
—£nsures that the mobile station and base station
remain connected while the BS and MSC
subscriber unit. Se
verifies
_*
Sa
.
Slow Associated Control Channe
l (SACCH ): On the forward link the SAC
Q regularly changing control inf CH is used to send slow but
ormation t o the mobile such a tran
the reverse link the SACCH carrie smit power level instruction. On
s inform ation about the received sign
yy Fast Associated Control
al strength.
Channel (FACC H): FACCH carries
' thesame type of informati urgent messages and contains esse
on as SDCCH, ntially
Necessity of Logical Channel a

in GSM System:
I practice, a multimode terminal used b
y a third generation (3G) mobile
network will have to communication system
scan for s uitable frequency band or channel, identify
Standard and select from application radio and
among the set or available services
If it develops at a very ,
large num ber of frequency ban
need to be searched ds need to be scanned and the man
registerin g such a roaming mul y standards
timode terminal by means of systematic

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 FF _ Basic
=e degrade quality of service f

broadcast channel calja4

‘Slobal radio control channel.
M system
to scan a single frequency oy ‘ a
eerimmalion on available networ k or ands

a i
tem
/i ; fl. this section we study we study messag
es and processing
Mti} Messag
Thees type
in s Gsmof: messages to be transmit
lf ted over the Reverse control
es s
chann el are Page re; =P OD
message, origination mess message.
age, order confirmation
* message and older fixed
; All messages contain an application message header, mandatory seen Mandatop
if , l variab
variable parameters, remaining length and optica "
le parameters
H i * The Mobile Station call processing in GSM
consists of the following four types:
bel 4] 1. Mobile station initiation state.
HA 2. _—s
Mobobl
ile statio
e sta tionn idl
idle
i i e Sta
state.
te.
3; System access state
a
i 4. Mobile station control on the traffic cha
nnel state. - ot
\{

| @
i |
1 1
Bsc MSC [——)| cGmsc
7 7 ?
ahi? 2/}2
i
a a

os ee tit
SJ) Fig. 1.3: Mobile Call Origination
in Gsm
Mobile Call Origination in GsM:

If the call is allowed, the MSC routes

the call to GMSC.
The GMSC routes the call to the local
exchange of called user,
e The LE alerts (applies ringing) thec e al
Answer back (ring back tone) from
the called terminal to LE.
Answer back signal is routed
back to the Ms through the Ser
speech path to the MS. ving MSc which also completes
thé

7"
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 Fig. 1.4: Mobile Call termination in GSM ’
Mobile Call Termination:
The PSTN user dials i MSISDN ofithe called user in GSM.
/
The LE routes the call to the GMSC of the called GSM user.
The GMSC uses the dialed MSISDN to determine the serving HLR for the GSM user and interrogates it
to obtain the required routing number.
The HLR requests the curr serving VLR for the called MS for a MSRN (MS roaming number) so that
—> <= ——— a

the can be routed to the correct MSC. “~h

&
The VLR passes the MSRN to the HLR. S ; °
The HLR passes the MSRN to the GMSC. | ~ a x < \ >
Using the MSRN, thero
GMSC utes
the call to the serving MSC. A* ne
The MSC interrogates the VLR for the current Location Area Identity (LAI) for the MS. \ ;
The VLR provides the current location for the MS. nie “i
The MSC pages MS via the appropriate BSS. The MS responds to the page and sets up the necessary
signaling links.
When the BSS has established the necessary radio links, the MSC is informed an the call is delivered
to the MS. When the MS answers the call, the connection is completed to the calling PSTN user. ~\

MOBILITY MANAGEMENT
eS management is one of the major functions of a GSM or eS network that allows mobile \
phones to work. we = oe

¢ The aim of mobility management is to track where t he subscribers.are, allowing calls, SMS and
other mobile phone services to be delivered to them.
—~

Diz. Location Update Procedure

A GSM or UMTS network, like all cellular networks, is basically a radio network of
individual cells,
known as base stations. Each base station covers
a small geographical area which is part of a
uniquely identified location area.
By integrating the coverage of each of these base stations,
a cellular network provides a radio
coverage over a much wider area. For GSM, a base station is calleda Base
Tra
and for UMTS it is called aWode B.\) group of base stations is named a locatio gr ae
n area, or a routing
area, ———

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!

: 5

itsc last fedate,caitte i

perfor ms oa :
€n a mobile finds that the aesmies et is iss
safere
iff ntt fro
Ogum she wiup
F
a. upda
mPorary Mobile Subscriber Identity (TMS!).
* The mobile also sto res the current LA In C
the SM card, concatenating a : losei not
LACS. This is done to avoid unnecessary
forced to switch off (by removing the battIMS ! attachment bien
ery, for example) without — g a he chance to +.
network with an IMSI detach and the Otify ahe
n switched on right after it has been tur
ne a a
* Considering the fact that the mob
Location Register (MSC/VLR) of theilecuris still associated with the Mob
rent location area, there is noileneeSwi
d tch
foringanyCenkin
terd/Vio¢g
IMs
attachment procedures to
be done,
* There are several Teasons why a mobile .
may provide updated location inf ;
ormation to the ne, 5
Whenever a mobile is switched
on or off, the network may req
IMSI detach location update uire it to perform an IMSI atta
procedure, ch g
* Also, each mobile is Fequired to reg :
ularly report its location at a
set time interval using a Periodi
location update Procedure. Whenever a mobile moves fro
on a call, a random location m one loc ation area to the next while ng
update is required.
* This is also required of a stationar
y mobile that reselects coverage fro
area, because of signal fade. Thus, m a cell in a different location |
a subscriber has reliable access to the
reached with a call, while enjoying the network and may }
freedom of mobility within the whole cov
* When a subscriber is Paged in an att erage area.
empt to delivera call or SMS and the
that page then the Subscriber subscriber does not reply to
is marked as absent in both the
Register (HLR) (Mobile not rea MSC/VLR and the Home Location
chable flag MNRF is set).
* The next time the mobile per
forms a location update, the HLR
reachable flag is cleared. is updated and the mobile not

Temporary Mobile Subscriber

Identity (TMS!)
“a The Temporary Mobile Subscr
iber Identity (TMSI) is the identi
the mobile and the network. ty that is most commonly sen
= t between
* TMSI is randomly assigned by the
VER to every mobil in the area, the
numb iser
local to a location are, , and so it has moment it is switched on. The
to be updated each time the mobile
geographical area. moves to a new
¢ The network can also change
the TMSI of the mobile at any
avoid the subscriber from bei time. And it hormally does
ng identified, and tracked by so, in order to
e This makes it difficult to €avesdroppers on the radio
trace which mobile is which, interface.
switched on, or when the dat except briefly, when the mob
a in the mobile becomes invali ile is just
e At that point, the global Int d for one rea son or ano ther.
ern
ational Mobile Subscriber
Identity (IMSI) must be sent
The IMSI is sent as rarely as to the network.
possible, to avoid it being ide
¢ Akey use of the TMS! is nti fie d and tracked.
in paging a mobile. "Pagin
g" is the one-to-one com
mobile and the base station. munication between the
¢ The most important use of bro
adcast information is to set up
channels for "paging" Every cell
system has a broadcast mechanism ulat
to distribute such information to a plu
rality of mobiles
* Size of TMSLis 4 octe with full hexdigits and can't be all FF because the SIM uses 4
equal to 1 to indicate that no valid TMS g isi ava Sa. uce t »IM use uses 4 4 octets
octets with its
with allal bits_
bit_
~

i —— GS
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 Wiraless and Mobile Network 11s Bas
of PCS
ic andsGSM

Roaming
+oamin
* g is one of the fundamental mobility management procedures of all cellular networks.
* Roaming is defined as the ability for a cellular customer to automatically make and receive voice
calls, send and receive data, or access other ces, including home data services, when travelling~
outside the geographical coverage area of the home network, by means of
using a visited network.
* This can be done by using a communication terminal or else just by using the subscriber identity in
the visited network. Roaming is technically supported by a mobility management, authentication,
authorization and billing procedures.

Types of Area:
q
= aS
&® Se
* The different types of area in wireless and mobile network are Location
area, Routing area, Tra ing
area. —_

4; tion Area: _————

_
A ‘location area" 4 is a set of base stations that are groupe tog imizeze sigsign
d ether to optimi nalalin
ingg.. Typ TypicFaally,
tens or even hundreds of base stat ions share a single Base Station Controller (BSC) in GSM, or a
ioRad
Network Controller (RNC) in UMTS.
* The BSC / RNC is the intelligence behind the base statio
ns; it handles allocation of radio channels,
receives measurements from the mobile
phones, and control s handovers from base station to base
station.
To each location area, a unique number called
a Location Area Code (LAC) is assigned. The
area code is location
broadcast by each base station at regular intervals.
* Within a location area, each base station
is assigned a distinct Cell Identifier (CI)
also Cell Global Identity. number, see
If the location areas are very large, there will be man
y mobiles operating simultaneously,
in very high paging traffi ¢, as every paging requ resulting
est has to be broadcast to every base
location area. station in the
This wastes bandwidth and power on the
mobile, by requiring it to listen for broa
much of the time. dcast messages too
If on the other hand, there are too man
y small location areas, the mobile must
very often for changes of location, which contact the network
will also drain the mobile's battery. A bala
wee struck. nce has therefore
+ Routing Area:
* The rouu ting areais the pac
ket-switched domain equivalent
norm of the location area , A "routing area” is
a al
subdivly
ision of a ‘Location Area". Routing
attached _- area s are used by mobiles which are GPRS-
— <7
* GPRS is optimized for “bursty” data a
communication services, such as
multimedia services. It is wir i
also known as GSM-IP ("
directly to Internet Servic
e
iy i
Pro

A change from routing are

a to routin § area (called
identical Way to a cha a "Routing Area Update") is done in an almost
n ge from locati
on area to location area.
Serving GPRS Support The main di fferences are that the
N Ode (SGSN) is the elemen
t involved.

}
ite
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 cking
ting area. A trai mn
: —— ‘ a n be
ea
alley
grouped into l i s t of tracking
oft areas
aioe Sndlibou
(TA ists), which can n be
Snowe Equipment(ug).
Tracking &rea updates are
Not included in its
en
performed
ee
odically or when the UE moves to a tracking
area th
ml
TA list, peri
4 Operators can allocate different TA ferent UEs. This can
avoid sign
ane a
lists to diffe Peaks in
Conditions for instance the UEs of passengers
simultaneously of a train may not p erform tracking area up da
wo aiitt Retwork side, the involved element is the nity Man
Mi agemen
a Configures TA lists using Mobility Man men t Entity (MME), »
Nas messages like Attach Accept, TAU Accept or GUTI Rez
Mand.

H EERY movitity mana gement (PCS)

Performance
of the Pcs networ
ovements of the k is significantly affected by the way the nettwo
wo rk m anages ‘th
mobile y Sers,
Pcs term Architecture:
The mobile Service area is
covered by a set of base stat
the calls to and from the ions
i (BSs)., which i ; seater cll
mobile Stations (MSs) loca onsible for re
* The BSs are connected to ted in thei r pov era ge a
mobile switching centers
MSC isa telephone exch (MSCs) by land links.
ange con figured Specifically for
BSs) with the PSTN. mobile applications, int
erfaces the MSs fy:

CS system
(@.g., thes ys
the system in Los Angeles), the tem in New York Ci
syste mM should be
in fo r,
ty) to another (eg:
Otherwise it would be impossible med of the
to de liver the Serv current loca
ices to the Mo tion of the
bi le user. user.

for PCS networks. ——_——

Ppli cation Part(MAP) have been define?

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 . When amoblle user is en ged In conversation, the MS is connected to » 8 via a radio link.
* Ifthe mobile user moves to the coverage area of another 88, the radio link to the old BB I —

disconnected, and 4 radio link to the new BS should be established to continue the conversation, ,
* This pr variously referred to as automatic link transfer, handover or handoff, Three
piorlss have been proposed to detect the need for handoff namely, Mobile - Controlled Handoff
(MCHO), Network-Controlled Handoff (NCHO) and Mobile-Asslsted Handoff (MAHO
),
1, Mobile-Controlled Handoff (MCHO);
* The MS continuously monitors the signals of the surrounding B85
and initiates the handoff process
when some handoff criteria are met.
* MCHO is used \n(DECT dnd Pacs,
2, Network-Controlled Handoff (NCHO):
* The surrounding BSs measure the signal from the MS, and the
network initiates the handoff procese,
when some handoff criteria are met,
* NCHO is used in CT-2 Plus and Amps en ee | 6 F
aw aa po ot. eee
3. Mobile-Assisted Handoff(MAHO): 4 9
* The network asks the MS to measure the signal from the surro . FR
unding 884. The network makes the
handoff decision based on reports from the MS.
* MAHOis used in GSM and IS-95 CDMA.
Two Typeof Hando
sff: —
1 The BSs involved in the handoff may be connected
to the sare MSC (inter-cell handoff or inter-
BS handoff)
2, The BSs involved in the handoff may be connected to
two different MCSs (intersystern handoff or
inter-MSC handoff)
Inter-BS Handoff:
The new and the old BSs are connected to the sarne MSC. Assume that the need for
detected by the MS. The following actions are taken: handoff {s
1, The MS momentarily suspends conversation
and initiates the handoff procedure by signaling
an idle (currently free) channel in the new BS. on
Then it resumes the conversation on the old
2 Upon receipt of the signal, the MSC transfers the BS.
encryption information to the selected idle
channel of the new BS and sets up the new conversation
path to the MS through that channel.
The switch bridges the new path with the
old path and informs the MS to transfer
channel to the new channel. from the old
3. After the MS has been transferred to the new # 5, It signals the network, and resumes
conversation using the new channel.
4. Upon receipt of the handoff completion
signal, the network removes the bridg
and releases resources associated e from the path
with the old channel.
This handoff procedure is used with the mobile
controlled handoff strategy.

o-@ O
i =|
i ! 1
| {

A K A
'

KA f b
' \
‘ j
New BS 1 Sige ion 08 aio 8° OWBg.
~

OldB
oa - > New
as ip
(8) Step1
meen 2 (4) Step 4 (a) Step4
Fig. 1.6, ;: Inter-B5 link transfer

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 “Mittless and Mobile Network
) 1.18
* Forthe network-controlled handoff strategy
tore - all handoff signali ng messages are exchanged },
the MS and the old BS though the failing link.
* The whole Process must be completed as quickly as poss ible, to ensure
aa Sala thatiree
the hana
new link ,
chaeab
€stablished before the old link fails. If the new BS does not ha a
may be dropped(or forced to terminate) ioeeoalitoe
* The forced termination probability
is an important eee to Deiat - ee ta ns
|
ibe, Forced termination of an ongoing call is considere
Wee ockin, i
* Most Pcs networks handle a handoff in the same manner
as a new ete t.che
That aes
is if no cha .
e, the handoff is blocked and the call is held on the current
ss availabl the
call is completed or when the failing link is no longer available.
* This is referred to as the non-prioritized scheme. These or
handoff schemes can significantly red
Ii the Probability of forced termination a i
as well as the probability of call inc t
J blocking plus handoff call for ompletion (new call )
Channel Assign
ced termination).
ment Schemes:
* To reduce forced terminati
on and t
have been Proposed, Reserved channel© pr omote call completion, three channel as
scheme, Queuing priori
j
: signment Schemes
ty scheme, subrating scheme .
1. Reserved Channel Sc
heme:
* Similar to the non-prioriti
zed scheme, except that some channels
handoff calls, in each BS are reserved for
2. Queuing Priority Scheme:
° Adjacent Coverage are
as of BSs may overlappe
d,
* Thus, there is considerable
area where a call can be han
handoff area, dled by either BS. This are
a is called the
If no channel is available
in the new Bs
waiting queue.

ith the old BS until either

a channel in the new BS
becomes
forced to terminate)
3. Subrating Scheme:

available in the new Bs.

Subrating means an occupied full rate
channel
original rate: one to serve the existing call, theo

rate channels.
Intersystem Handoff:

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 (a) Before the handoff (a) After the handoff
Fig. 1.7: Intersystem handoff
Intersystem Handoff Requires the Following Steps:
Step 1: MSC A requests MSC B to perform handoff measurements on the call in progress. MSC B then
selects a candidate BS2,BS2 and interrogates it for signal quality parameters on the call in progress. MSC
B returns the signal quality parameter values, along with other relevant information, to MSC A.
Step 2: MSC A checks if the MS has made too many handoffs recently. (this is to avoid, for example
numerous handoffs between BS1 and BS2 a where the MS is moving within the overlapped area) or
if intersystem trunks are not available. If so, MSC A exits the procedure. Otherwise, MSC
A asks MSC 8 to
Set up a voice channel. Assuming that a voice channel is available in BS2,MSC B instructs
MSC A to start
the radio link transfer.
Step 3: MSC A sends the MS a handoff order. The MS synchronizes to BS2. After the
MS is connected to
BS2, MSC B informs MSC A that the handoff is successful. MSC A then
connects the call path(trunk) to
MSC B and completes the handoff procedure,
* In this intersystem handoff process, MSC A is referred to as the anchor
MSC, and is always in the call
path before and after the handoff, as illustrated in the four cases in Fig.
1.8.
* This anchor approach is used in all existing mobile phone networks
because the re-establishment of
@ new call path(without involving MSC A) between MS and the
new MSC would require extra trunk
release/setup operations in PSTN, which is not available or is not cost-eff
ective.
* Ifthe MS moves back to MSC A again, the connection between
MSC A and MSC B is removed (handoff
backward). If the MS moves to the third MSC C ,then MSC B will be
in the call path(handoff to third).
* Note that when the MS moves to the third MSC, the second
MSC may be removed from the call path,
That is, the link between MSC B and MSC A is disconnected and MSC C connects to MSC A directly.
This process is called path minimization,

\ g x
‘ 9

(0) Handoff to the third

(d) Path minimization
Fig. 1.8: Handoff forward, handof
f backward, and handoff to the
third Roaming Management:

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 the , | es the MS.Location
systemsytem locat :
a callto the mobile user: jards
the IS-41 and GSM MAP stan are N04
ases.
Home 1 in tha: they use a two-tier system of home and visited datab

sa ae rd is created in the systems’ qa.)

: oe thehe See
e home location ee paras oeis re fe
This ieatie home system oaof theeemobile
‘ User,»
| '
The HLR is a network database that stores and manages all mobile subscrip fas De
Operator,
* Specifically, the HLR is the location register to which an MS identity is ee
i pi ih.
PUrpogg
such as di
rectory number, profile information, current location and validation p :
Visitor Loca tion Register (VLR):
When the mobile use “al
Mobile user js creat
r visi ts a PCS net work other than the home system, a
ed in the visitor loca temporary recorg for th
The VLR tempor tion ce yarex(win) or the vi
arily stores sited system.
corresponding Subscription information for the visiting subscribers go that th
MSC can provid €
service.
€r words, the VLR is the “other” loca
Calls to or from a visiting tion register used to retrieve in for
mation for hang ing
Mobile user,

Visitor location register Home location register

Los Angeles, California

New York City, Ne
Fig. 1.9: Ms registra w York _|
Registration Procedur tion Process
e:

moves from one visited sys

tem
VLR of the new visited system
.

the new VLR. The HLR sends an acknow :

ledgement ‘Which includes the MS's os of
pr nt location-the address

forwarded to the VLR for approval.

¢ If the call is accepted, the Msc sets
setup procedure.

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Wireless and Mobile Network 1.21 Basics
of PCS and GSM
Step 1: If a wireline phone attempts to call a mobile subscriber, the call is forwarded to a switch,
called the originating switch in the PSTN, which queries the HLR to find the current VLR of the MS(1).
The HLR queries the VLR in which the MS resides to get a routable address(2). If the originating switch is
not capable of querying the HLR(i.e. it is not equipped to support mobility),the call is routed through the
PSTN to the subscribers gateway MSC, which queries the HLR to determine the current VLR serving the
MS.
Step 2: The VLR returns the routable address to the originating switch through the HLR,
Step 3: Based on the routable address, a trunk (voice circuit) is set up from the originating switch to
the MS through the visited Msc.

Fig. 1.10 : Call delivery procedure

Roaming Management Under $$7:
* The missing parts in the picture are the interactions between the PCS network and the PSTN.
* This section briefly describes how mobile roaming is managed by the PSTN signaling.
Common Channel Signaling(CCs):
* Common channel signaling (CCS) is a signaling method that provides control and Management
functions in the telephone network. CCS consists of supervisory functions, addressing and call
information provisioning.
ACCS channel conveys messages to initiate and terminate calls, determine the status of some part of
the network and controls the amount of traffic allowed. CCS uses a separate out-of-band signaling
network to carry signaling messages.
S87;
* Signaling System No 7(SS7) is a CCS system developed to satisfy the telephone operating companies
requirements for an improvement to the earlier signaling systems, which lacked the sophistication
requiredto deliver much more than Plain Old Telephone Service (POTS).
Signaling between a PCS network and the PSTN are typically achieved by the $S7 network. In this
network, the trunks (voice circuits) connect SSPs to carry user data/voice information.
The signaling links connect SCPs to STPs, and STPs to SSPs. The SSPs and SCPs are connected
indirectly through STPs.
Signaling
links

Ly swe stp
(HLR)
SCP : Service Control Point
STP ; Signal Transfer Point
SSP : Service Switching Point

Trunk

PSTN | PCN(PCS Network)

Fig. 1.11: Interconnection between a PCS network and the PSTN

lll
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 . ig em 1.22 TCs ng
net Shows the network elements that are involved in the interconnection between
rk an
representa en
tr _ © PSTN. In the fig the dashed lines represent the signaling links, the Solig a
Thes
87 network Consists of three distinct components ’
namely, Service Switching Point (Sspy ;
1, Point (st p) 4nd Service Contro
l Point (SCP).
ice Swi Point(ssp);
eee Switch interconnected by $87 links. The SSPs perform call processing oy, cally
A .

» tandem, or terminate at that

Al node,
> ieee,obilein Switching
the PSTN canCenter
be a (MSC),
Central Office (CO) or End Office (EO). An SSP in a peg Netwgy,
* Signal Transfer Point
A swit ch that
(sp);
relays $s7 messages betwee ne
n twork switches and database
Based on the ad dress s.
Signaling Bike Yo an fields of the ss7 messages, the STPs route the
messages to the correct oy
as shown in Fig. t the stringent reliability requirements, STPs
are provisioned in mated pa,
Service Control Point(scp);
Contains datab ases for
returns the reques t providij
Provid ;
ing enhanced services, An SCP accepts queries from an ssp
a VLR €d information to the SSP. In mobile applications, an
SCP may contain an Hip a

iigae u. “oO
oe os -
ec -
gh = agess
cia
¢ ce” “ @ mo : N (HLR4 )
Cd
£ sf
‘SON
c
Se é Global ‘ \
4 f title Nay
¢ at translation
é ’
/ STP2 —
>| STP3
‘ @) (3) } STP4
/ - I
|
\
\
VLR) LR2) 3
MSC1 s MSC2
ee —

SS
Fig. 1.12; Registrati
on through ss7
Registration:
e Inthis example, the MS moves from VLR1 to VLR2
Step 1: The MS enters the area controlled by MSC2
.Msc2 launch ‘agi
through STP2,assuming that VLR2 and MSC2 are not co-located, &8 @ regis trati:on query to its VIR
Step 2: VLR2 sends a registration message to the MS's HLR.
HLR. Instead,VLR2 sends the message containing the MS identi VLR2 may not know the actual
call : add ressionof
tificat
Number(MIN),to an STP that can translate the MIN into the HLR Ss ed the Mobil e Iden
Step 3: The MIN-to-HLR address tran
slation is performed at STp3 by a
Global Title Translation(GTT). STP3 then forwards the registration fiestage table
x a -
techhniq
niq ue called

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 Wireless and Mobile Network 1.29 Basics of PCS and GSM
Step 4: After the registration, HLR sends an acknowledgement back to VLR2. Since the address of
VLR2 is known, the acknowledgement may be sent to VLR2 using a shortcut, without passing through
STP3.
Step 5: After step3,HLR sends a deregistration message to VLR1 to cancel the obsolete record.VLR1
then acknowledges the cancellation,
In steps 2, 3, 4 and 5, the messages may visit several STPs before arriving at their destinations, and
the registration process may generate considerable traffic in the $87 network.
e Thusitis desirable to reduce the registration traffic,
e Two approaches have been proposed to reduce the “cost” of deregistration at step 5. Implicit
deregistration, periodic re-registration,
Implicit Deregistration:
* Obsolete VLR records are not deleted until the database is
full.
e Ifthe database is full when an MS arrives, a record is deleted, freeing storage
space to accommodate
the newly arrived MS.
* Areplacement policy is required to select a record for replacement (it is possible that
a valid record
is replaced, and the information is lost),
Advantage: No deregistration messages are sent among the SS7 network
elements.
Periodic re-registration:
¢ The MS periodically reregisters to the VLR. If the VLR does not receive the re-regis
tration message
within a timeout period, the record is deleted.
* This approach only creates local message traffic between the MSC and the VLR.
Furthermore no $S7
signaling messages are generated if the VLR is co-located with the MSC.
Pointer Forwarding Scheme:
* To reduce the registration traffic at steps 2 and 3 in Fig. 1.13, a pointer forwarding scheme was
proposed which consists of two operations: Move operation (registration), Find operation (call
delivery).
Move Operation (Registration):
* When an MS moves from one VLR to another, a pointer is created from the old VLR to the new VLR.
* Noregistration to the HLR is required.
Find Operation (Call Delivery):
* When the HLR attempts to locate the MS for call delivery, the pointer chain is traced. After the find
operation, the HLR points directly to the destination VL.

— ee ew ee ee ee ee

(a) More operation (a) Find operation

Fig. 1.13 : Pointer forwarding scheme
* Depending on the memory capacities of the VLRs,
the pointers in the obsolete chain May not be
deleted. To limit the pointer traversal time
in the
1.12 may be performed for every k move operations find operation, the registration procedure in Fig
,

een

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‘Wirelees and Mabie Network 1.24 ~ etP CS
* Inother d operation will be limited byk 7
Words, the number Se Ee - a one net cost of pointer creation amet
* ‘raversal
AS performance than theindicate,
is higherstudies HLR.
ceintee theforwarding
accessing
cost of the q
scheme significantly reduces the J
A 2, in many cases.
* Similtoar
the registration process, visits to several STPs anda GTT may be required to Access
in call delivery, Several STPs may be visited to obtain the routable address from the VLR.
* To reduce the call delivery traffic, a cache scheme was proposed to maintain a
Srammece Another possibility is to maintain the cache in the STP that performs Ory. ny
.
& cache entry consists of two fields: the MIN of an MS and the address of the current Visited y
the MS. The cache contains entries for MSs recently accessed from the SSP.
* When the calling party ori
ginates a call to an MS, the SSP first checks if the cache en
exists. There are three possibilities: vy ioe the}
cman cache entry does not exist. The call
delivery procedure illustrated in Fig, 1.45.
howe ae entry exists and is current. The VLR
is directly accessed as shown in Fig. 1,
"Cache entry exists but is obsolete. The procedure dete
the cts that the cache entry is a
queried
‘
VLR's” resp onse is negative. The call delivery procedure is
:
illustrated in Fig. 1.15

--©. , (HLR)
: 2 - Global
title e

STP3
sm ht? PSTN
@) L{2)- > STP
\
Ly XA

(HLR)

ween oo ~~) through 557

- i >

f bdrm a ~.

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 eS !)lU!lCl

Wireless and Mobile Network 1,28 _Bas and GSM

of PCSice

Discussion: wv acai)
¢ Note that implicit deregistration and periodic re-registration can be used with the cache scheme, but
the obsolete cache information may not be detected until the MS is paged,
« Since the cache information may be obsolete, some heuristics are required to determine whether the
cached information will be used to locate the MS.
* One technique is to have the SSP estimate the cache hit ratio, or the probability that case 2 is true, If
the coral is high, the entry is considered “current” and is enabled; otherwise the entry is
disabled,
+ Another heuristic determines the obsoleteness of an entry based on the period that an MS resides
a VLR as indicated in the cache entry,
in
e If the cache entry indicates that the MS has stayed in a VLR for a period longer than a specified
threshold, the entry is assumed to be obsolete.
e The threshold can be adjusted in real time based on cache hit statistics, If case 3 is more likely to
| occur than case 2, then the cache scheme should not be considered.
* Performance studies indicate that the cache scheme significantly seduces the call delivery cost in
| many case.
Roaming Management for CT-2:
* Ina public environment,CT2 is a one-way calling PCS system; that is a CT2 handset can originate
outgoing calls, but cannot receive incoming calls.
* We describe how to construct two-way calling mechanism in to CT2.As we will demonstrate later,
introducing roaming management for CT2 is expensive.
« Nevertheless, this introduction provides a model so that the reader can understand the design
complexity required to implement a total mobility solution for an one-way PCS system.
Basic Public CT2 System (One-WAY calling):
* Fig. 1.16 shows basic public CT2 system.
Ct2 Control
system

Fig. 1.16 : Basic Public CT2 System

* The original public CT2 system was designed as a tele-point service, and did not support call delivery.
CT2 BS is connected directly to a switch in the PSTN.
* The CT2 control system is responsible for monitoring and building, which may be connected
indirectly to the BSs through the PSTN,
¢ The messages between the CT2 control system and the BSs are delivered through the PSTN. CT2
as
system csn provide only the call origination service, It is impossible to provide call delivery service
in cellular systems such as DAMPS and GSM. ,
* Some CT2 systems (eg. the systems in Hong Kong) utilized the paging system to provide call delivery;
the paging
thus when a wireline user A wanted to call a CT2 user B, A would first page B through
system. hth
A through the
* From the paging message, B identified the telephone number of A, then dialed back to
| CT2 system.
Advantage:
1. No modifications are made to the CT2 architecture,

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 .

The inconvenience caused by the involvement of the paging sys tem and thus for the ; re,

nati e. A and B use CT2 handsets in different CT2 systems it is imposs ible to connect the cay,
if both
~at-a-Junction cT2 i

. An advanced cr2 System (Two-Way Calling): ction” approach to pr ovide th € call dey
capability, System may follow the “meet-at-a-jun
“me Veren
.
ang CT2 architecture for this approach js illustrated in Fig. 1,16.
. 7
this approach, the cr2 service area is partitioned in to several location areas.
“<All
location area are connected to an area controller.
same Switched Data Network (PSDN) all area controllers are con me,
° BSs in thethe Public
Through o the data
called the location reg
ister.

Area
controller
Fig. 1.17: Meet-at-a-junction architecture

Signaling ——_
Trunk ——

Fig. 1.18 : CT2 call delivery procedur

e
Call Delivery Procedure:
e Ahandset will register at the location register after it enters a location area. A location
record for the
handset is created in the location register, which indicates the location
area-the address of thé
corresponding area controller, where the handset resides,

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 Wireless and Mobile Network 1.27 Basics of PCS and GSM
e From the registration list of the location register, the BSs poll the handsets periodically.
If the polled
handset does not reply, the CT2 system assumes that the handset has left the location area and the
handset’s location is deleted.
+ Ifa handset does not receive the polling message for a long time, for example when the handset
moves to a new location area and the movement is not known by the location register, the
handset
registers to reclaim its existence.
* Thecall delivery procedure is described in the following
steps:
Step 1: When the calling party dials the number of a CT2 handset, a voice
trunk is set up from the
originating switch to the CT2 switch $1.
Step 2: Sl queries the location register to identify the area controller
of the handset.
Step 3: An alerting message is sent from $1 to the corresponding area controller via the PSDN. The
area controller then broadcasts the alerting message to the connected BSs to page the handset.
Step 4: If the handset responds, the corresponding base station redials to $1 through the PSTN.
Step 5: 51 bridges the two trunks, and the conversation begins.
* Two dials are required in the call delivery procedure: One from the originating switch to $1 and the
other from the BS to S1.
* The CT2 modifications for two-way calling services have been considered expensive. In Taiwan, for
example, a CT2 call delivery was considered as two phone calls.
* The CT2 services in Hong Kong were terminated in 1996.In the same year, many European countries
replaced CT2 by DECT as the standard cordless technology. In Taiwan, the bandwidth for CT2 was
reclaimed for PACS and PHSin2000.

GSM Mobility Management

+ 41g 1.17 shows mobility management in GSM.

Call to Nr
CC] re 085-123456

User SIM card Terminal

(identifier : MSISDN) (identifier: MSI) (identifiwer IMEI)

SIM : Subscriber Identity Module

IMS! : International Mobile Subscriber Identity ~ MSISDN IMSI
IMEI : International Mobile Equipment Identity 085-123456 208347854033
MSISDN : Mobile Station ISDN Number

Fig. 1.19 : GSM Mobility Management

* GSM networks track the locations of the MSs so that incoming calls can be delivered to subscribers. A
mobile service area is partitioned into several Location Area (LAs) or registration areas LA consists of
a group of Base Transceiver Stations (BTSs) that communicate with the MSs over radio links.
GSM Location Area Hierarchy:
In GSM, registration or location update occurs when an MS moves from one LA to another,
* Basic Location Update Procedure contains Inter-LA Movement, Inter-MSC Movement and Inter-VLR
Movement. MS cannot distinguish the types of movement

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 HLR ; HOME Location Register
VLR : VISITOR Location Register
MSC : Mobile Switching Center
LA : Location Area
MS : Mobile Station
Fig. 1.20
Step 1: Th © MS moves from LA1 to LA2, where both LAs are connected to the same MSc
location update réquest message is sent from
the previous the MS to the MSC through the BTS, include the ada...
a ly. vis;
a LA, MSC, and VLR TMS is used to avoid sending the
IMSI on the radio path
Step Twards the location update request to
the VLR b y a TCAP message,
MAP_UPDATE LOCATION_AREA
_
Address of the MSc
TMSI of the Ms
Previous location are
a identification (LAI)
Target LAI

MSC updates the LAI field

the 0 f the VLR
record, and . ,
MSC Fig. 1.21 Inter-La registration message cube 12). nwledament to the MS thre

Fig. 1.21; Inter-LA registration

Message flow

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 Wirele
and Mobile
ss Network 1.29 Basics of PCS and GSM
« TwoLAs belong to different MSCs of the same VLR
Steps 1 and 2: The location update request is sent from the MS to the VLR
Step 3: VLR updates the LAI and the MSC fields of VLR record, and derives the HLR addres
s of the MS
from the MS’s IMSI.
VLR sends the MAP_UPDATE_LOCATION message to the HLR
IMSI of the MS
Address of the target MSC (i.e., MSC2)
Address of the target VLR (i.e., VLR1)
Step 4: HLR identifies the MS's record by using
the received IMSI
MSC number field is updated
An acknowledgment is sent to the VLR
Step 5 and 6; Similar to steps 3 and 4 in Inter-LA
Movement

oe ©
MSCL VLRI HLRL
2. MAP_UPDATE_LOCATION_AREA
”|3. MAP_UPDATE_LOCATION
4. MAP_UPDATE_LOCATION_ACK
5, MAP_UPDATE_LOCATION_AREA_ack

Fig. 1.22 : Inter -MSC registration message flow

Inter-VLR Movement
* Two LAs belong to MSCs connected to different VLRs
Step 1: Location update request is sent from MS to VLR
Step 2 and 3: VLR2 identifies address of the previous
VLR(VLR1), then sends the message
MAP_SEND_IDENTIFICATION to VLR1
TMSI
VLR1 sends IMSI to VLR2.
Step 4 and 5: VLR2 creates a VLR record for the MS,
and sends a registration message to update the
HLR,
HLR updates MSC and VLR address field of the record.
An acknowledgment is sent back to VLR2.
Step 6: VLR2 generates a new TMSI and sends it to the
MS.
Step 7 and 8: The obsolete record of the
MS in VLR1 is deleted.

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 4. MAP_UPDATE_LOCATION
5. MAP_UPOATE_LOCATION

le.MAP_CANCEL_LOCATION
Two Issues of Gsw bil ‘ Inter-VLR registration message flow

ent

| VLR Information Consists of3 parts; Fvice area Visi

pose are Stored jn VLR. ted by Ms. All subscriber da’ a 0
(i) Mobile station Informatio
n
* IMs!
* MSISDN
* ‘TMS!
(ii) Location Information
{ * MSCnumber
| * Location Area Ip (LAI)

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 Wirel
andess
Mobile Network 1.31 Basica of PCS and GSM
(iii) Service Information
e Subset of the service information stored in the HLR
VLR Failure Restoration
* Service Information of a VLR record recovered by - The first contact
between the VLR and the HLR of
the corresponding MS.
¢ Location Information of a VLR record recovere
d by
o First radio contact between the VLR and
the MS
o Mobile Station Information of a VLR record reco
vered by
o Either by contact with the HLR or the MS
o VLRrecord restoration is initiated by one
of the three events
1. MS registration
2. MS call origination
3. MS call termination,
ecord Restoration Initiation Event
1;
MS Registration:
VLR considers the registration as inter-VLR movement
because VLR record was erased by failure. VLR
record is recovered from normal inter-VLR movem
ent.
MS is asked to send IMSI over the air because TMS] send from
MS to the VLR cannot be recognized.
VLR Record Restoration Initiation Event 2:
2. MS Call Origination:
VLR received the call origination request from MSC. Becaus
e the VLR record for MS is not found, VLR
considers the situation as a system error “unidentified subscr
iber”.
* The request is rejected, and MS is asked to initiate location registr
ation procedure.
Call Termination Message (Failure Restoration):
VLR Record Restoration Initiation Event 3— MS Call Termination:
Steps 1-3: Similar to the first three steps of basic call
termination procedure, VLR is queried to
provide the MSRN. Because searching for MS record by using
IMSI fails, VLR creates a VLR record for MS
Neither service nor location information is available, Steps
4 and 5 are executed in parallel.
Steps 4 and 7: VLR create MSRN using MSC numbe
r provide by MAP_PROVIDE_ROAMING_NUMBER
message. MSRN is sent back to GMSC to set up callin step 8
Steps 5 and 6: VLR recovers service information of VLR
record by sending MAP_RESTORE_ DATA
message to HLR. HLR sends the service information to VLR
using MAP_INSERT_SUBSCRIBER_DATA
message. Location information, specially LAI number
will be recovered at step 11
Step 8: GMSC sends SS7 ISUP message IAM to target MSC.
Steps 9-11: MSC sends message MAP_SEND_INFO_FO
R_INCOMICALL
NG to VLR to obtain LAI
information. VLR does not have LA] information, and
sends. MAP_SEARCH_FOR_MOBILE_SUBSCRIBER to
MSC to determine the LA of the MS. MSC initiates paging
of the MS in all Las
Steps 12 and 13: If paging is successfu l, the current LA addre
ss of the MS is sent back to VLR by
MAP_PROCESS_ ACCESS_REQUEST message

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 Originating switch
G SMC
HLR
i lA. ISUP 1AM
j
=
2. MAP_SEND ROUTING
|
a
ineoRMarion

4, MAP_PROVIDE_RO
AMING_N
5. MAP_RESTORE pa
ra
5.MAP_Res TORE_DATA-ac
k
6
6 wINSERT
a; MAP_SEND _SUBSCRIB
ROUT; NG ~' ER DATA_ack
NFORMATIOn
ack
5. ISUP Lay
9 Ot
NEO FOR N
hs sopacmaR
10. MAP_SEAR
CH FoR 14
12.MAP pp

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 f =
i

, the data in the backup are reloaded into the HLR. An Uncovered Peri
i

the last backup operation and before the restart of the MLR.
step 4: The HLR sends an $87 TCAP message MAP_RESET to the VLRs where its MSs are located.
Step 2: All the VLRs derive all MSs of the HLR. For each MS, they send an $S7 TCAP message,
the HLR.
MAP_UPDATE_LOCAtoTION,
The HLR restoration procedure is not robust. - An MS may move into a VLR (which does not have any
other MSs from the given HLR residing) during the uncovered period. ~ The new location Is not :
known to the HLR at the last check-pointing time.
If'so, the HLR will not be locate the VLR of the MS during Step 1 of HLR restoration. VLR Identification
Algorithm is to solve the problem,
):
algorithm (VIA) (1/3description,
To simply the we assume that every VLR covers exactly one MSC. To implement VIA,
extra data structures are required.
In the backup, the extra data structure is a set VLR_List* of VLRs that have been modified during the
uncovered period. After an HLR failure, the HLR only needs to send the MAP_RESET messages to VLRs
eee eee ee ee ee eee eee ee eee
4 ! Cis]
1 HLR*
:' VLR_List® | HLR VLR_Counter
| Ms VLR '
1
vir |! MS | PVLR| ts | VLR VLR | Count
,
i
'
Vv, ' Vv,
4 \
‘ \
‘ 1
V2
V2
‘
1
'
;
1
Va V3
i
‘ Va
4 Va |
'
Y\ \
1
1
i \
1 Backup (Non-volatile storgae) \ fo
J
|

Fig. 1.26 ; HLR architecture

In HLR, every record includes two extra fields.
The ts field = the last time of location update
ng time. Thus, for any
The PVLR field = the address of VLR where the resided at the last check-pointi
MS p, we have
HLR’(p).VLR = HLR[p].PVLR
Two extra data structures are introduced in the HLR.
TS = the last check-pointing or backup time
the “effective
VLR_Counter = {(VLR1,Count), (VLR2,Count), .... (VLRn, Count)} where Count represents
number” of MSs entering the VLR VLRn during the uncovered period.
uncovered period.
AnMSis not effective to a VLR if it entered the VLR area then left the area during
st*,
Note that the VLRs recorded in VLR_Counter are the VLRs in VLR_Li
VIA Procedure 1: Check-Pointing
by this procedure.
In VIA, information of the HLR is periodically saved into the backup
Step 1: For every entry p in HLR* do:
HLR{p]’. VLR <- HLR[p).VLR;
Step 2: TS <- current time;

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 Step 1. Update HLR:
Vold <- aoe VLR entry of p at Vold; ,
ey cant, LOCATION to cancel the
Send message, MAP_
HLR[p].VLR <- Vnew;
told <- HLR[p].ts;
HLR[p].ts <- t}
VIA Procedure2: Registration (2/3) a
Step 2 : Update the Vnew Count field in VLR_Counte
If (HLR[p].VLR <> HLR[p].PVLR){
If (VLR_Counter[Vnew] exists){

VLR_Counter[Vnew].Count <-VLR_Counter[Vnew] .Count+ 1;

}elsef
create VLR_Counter[Vnew] and VLR_List*[Vnew];
VLR_Counter[Vnew] <- 1;
+ }
VIA Procedure 2: Registration (3/3)
St
3:ep
Update the Vold counter entry:
If (told > TS and Vold «> HLR[p].PVLR){
VLR_Counter[Vold].Count <- VLR_Counter[Vold].Co
unt - 1;
If (VLR_Counter[Vold].count = Q){
Delete VLR_Counter[Vold] and VLR_List*[
Vold];
i

}
VIA Procedure 3: Restore
Step 1: TS <- current time;
Step 2;
for (every location entry p in HLR){
HLR[p).PLVR = HLR[p].VLR <- HLR[p]*. VLR; HLR[p).ts <- TS:
}
Step 3:
for (every VLR entry VinVLR_List*){
Send an SS7 TCAP
M, _RESET Message
VLR Overflow Control: to y.
. ne es of records in the
VLR can
Betisivcusins€ corre: call
eee i a
be larger than that a Ti
in eei that the number © .1!
. When a VLR is full, the :
> incomin a short p e r ; and th
. Problem, overflow & Mobilei users Period, erflom
control algorithms
0-1, o-17 Hee oN mat
An extra flag (1 bit) is required "egister using the reciahue
Overflow in the HLR rec ! /and 0.
solve #
Registration Operation: are pres “istration. a
* Fig. 1.27 shows overflow oe
registration read
Peration
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‘Wireless and Mobile Network 1.35 of PCS and GSM
Basics

Step 2
Fig. 1.27 : Overflow registration operation
Algorithm 0-1: Registration
Step 1; Registration Request;
Step 1.1: Same as step 1 of the normal registration procedure
Step 1.2 : V2 is full. V2 follows a replacement policy to select a record to be deleted (u2in Fig. 1.28).
The storage for the delete record is used to store u1's information. The selected user (i.e., u3) is called
overflow user. The replacement policy may be based on various heuristics
Step 1.3 : V2 forwards the registration request to the HLR with indication that u3's record is delete
due to database overflow Cont.
Step 2; Registration Response:
Step 2.1: HLR update the location of u1, and sets the overflow flag in u3's record
Step 2.2: HLR acknowledges the registration operation and sends 1's profile to V2.
Step 2.3 V2 sends an acknowledgment to MS
Cancellation Operation with Overflow VLR

Before the registration After the registration

operation operation (V1 may
not be accessed for
de-registration)
Fig. 1.28 ; Cancellation operation with overflow VLR
Algorithm 0-II: Cancellation:
If ui is an overflow user at Vi, then u1 does not havea record in V1
Cancellation operation simply resets the overflow flag of u1's HLR record if u1is not an overflow user in
V2
Algorithm 0-111: Call Origination:
Step 1: The MS sends the call origination request to V2
Step 2: V2 cannot fine u1'srecord, and denies the call request.
Steps 3 and 4: The MS initiates the registration procedure; Algorithm O-I is executed.
Steps 5 and 6: The MS reissues the call origination request, and the normal call origination
Procedure is executed.
Call Origination with Overflow VLR Call:
Fig. 1.29 shows call origination with overflow VLR.

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 oe ' SEND_I FOR_OUTGOING_CALL

seaseeiower
: NFO.
AUTGOING CALL_2ck |
* (een
4 MAP. ay LOCATIC EA_ack

Algorithm 0-1
4, MAP_UPDATE_LOCATION_AREA_ack
5. MAP SEND_INFO_FOR_OUTGOING_CALL

Normal Call Origination Procedure

6. MAP_SEND_INFO_FOR_OUTGOING_CALL_ack |

Termination with Overflow Fig. 1.29 : Call origin

withat
overio
flow n
VLR
VLR,

Dis.
Fig. 1.30: call termin
ation with overf]
Step 1 : Location query:
Step 11: The calli

Step 1.2: The originat

ion switch sends a lo
Step 1.3: The HL
R determines th
routing information at Ulisa
The use profile in form
Step 2: Locati atio
on response:
Step 2.1: If V2 is not ful
l, a record f
Store ul and sends jt Or ul is created, 1
record is replaced — son HLR. V2 crea tes the routable addresfull, ; Us
V2 is :
s er record is deleted and is«useusd
Step 2.23
2 ae returnep.s ce
thement
routinabfo
lermat
addrioe,n is included in the w
overflow flags are updated at th Messt
age “ends it back to the .
e Hip a2 the °riginating switch If
Step 2.3 : The originati a record is replaced!
‘ is LU
s eteop :T
2.4: h The MscgiPa
nage
tison thswe itmochbile
sets Phuponetheanru
With Algorithms 0-1 through 0- d nk
the tocalth
}e msc b
Se d on the routable addr
IV, an EA Can ar Path js €stablisheq ess
long as the number of simultan
©ous Phone calls sommoda
to these users j,
an
=

a eae
"ger thanth e
the size of the datay™’
Wireless and Mobile Network 1.37 Basics
of PCS and GSM.

Termination with Overflow VLR

e Fig. 1.31 shows call termination with overflow VLR.

<i
2.1

x9
Fig. 1.31: Call termination with overflow VLR

ETWORK SIGNALING
¢ To support PCS network management, protocols such as EIA/TIA Interim Standard 41 (IS-41 also
known as ANSI-41) and Global system for Mobile communications (GSM), and Mobile Application
Part(MAP) have been defined for PCS Network (PCN) intersystem operations.
¢ Interactions between a PCN and the PSTN are addressed in four aspects namely, Interconnection
interfaces, Message routing, Mobility management and call control.
Signaling System No 7:
* PSTN isa signaling protocol. The interconnection between a PCN and the PSTN there are six types of
$$7 signaling links. es
* Two types, A-Link(access link) and D-Link (diagonal link).
D-Link 8 SS7 protocol Layers

A-Link STP STP fy A-Link OS! Layers _ The SS7 Layers

APY le OMAP] | MAP
E (SCP) Application |
_ 4) TCAP
A-Link ISDN-UP
A-Link
Presentation
Session Transport
Trunk] fon) a ee
(ss) SCCP

PSTN | PCNI(PCS Network) |

ee MTP Level 3
Data Link MTP Level 2 ae
Physical MTP Level 1 054
Fig. 1.32 Fig. 1.33 : SS7 protocol Layers
MTP (Message Transfer Part) :
* Transfer signaling information
* MIP Level 2 provides reliable transfer of signaling message
* MIP Level 3 provides message routing and network management.
SCCP (Signaling Connection Control Part):
* Provides additional functions such as GTT to the MTP

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 mid [7 Hons ne 5
x i
worCek . rc 1,38

Provides the Capability

to exchange information between using noncircuit-relateq ten a
tal ve ted Services Digital Network User Part):
a Circuit-switched network connections
OMAP (Operations
Mai
Application of reap ntenance, and Administration Part):
APPLICATION Part):
* Application ofTcap
. 'S-41 and GSM MAP are imp
lemented at this layer.
on and Message Rou
_ Message routing is perfortin g
med at the MTP and the SCCP
" €S are delivered of a node(ssp, stp
With the actual destination address at the MI °F SCP) g
-
:
P.
receives Messages from TCAP, SCCP,
..ue_—)) id
Uniq
USing ] entifies the destinat ISUP. DPC(destinatio nN point Cod
Ookup tables. io n no de , Routing to the dest e) of the
ination node js determin
eg by

STP Typa S (A-Links)

STP id | STP

Type 24 Type § (DLinks)

\\SS7 inte ce Type 2A with
f _ MSc SS7 intertd ce

PSTN|[PCN
a

S (A-Links)

Type 2B wth
“Eng 557 interfz ce
Office

PSTNIPCN

Mobility Manag Fig. 1.34, Inte

ement rconnection
using TCap, and Megs
TCAP Operation:
ome
* More than50
TCAP Operatio
n
roaming, operations
, adminis
TCAP message cons
ists of two Portions;
1. Transaction portion-de
fine Package type
Query with permission, Re
sponse
2. Component portion-de
fine numb: €ra
INVOKE, RETURN RESU nd types
LT of compo
RETURN ERROR, REJECT nents

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Wiroless and Mobile Network 1,39 Basics of PCS and Gsm

PCN! PSTN PCN2

Registration notification (INVOKE)

Registration Notification (INVOKE)

@ Registration Notification turn Result)
® Registration Cancellation INVOKE) ieee Notification (Return Result)
Registration Cancellation 1Return Resull)
Registration Cancellation (INVOKE)
|Registration Cancellation (Return Result)
Qualification Request (INVOKE)
® Qualification Request (Refurn Result)

Service Profile Request

a) Service Profile Request (Return Result)

Fig. 1.35 : Mobility Management Using TCAP

IS-41 TCAP Message flow for MS Registration:
1 Transaction 1 : When MS is in MSC2 service area, MSC2 sends a Registration
Notification(INVOKE) to its VLR(VLR2).
2, Transaction 2 ; If MSC1 is net served by VLR2, then VLR2 sends a Registration Notification
(INVOKE) to the MS’s HLR.
3. Transaction 3 : HLR sends a Registration cancellation (INVOKE) to the MS's previously visited
VLR (VLR1).
4. Transaction 4: The cancellation propagates to MSC1
5. Transaction 5: After T2 is completed,VLR2 creates a registration record for MS. Sends a
Qualification Request (INVOKE) to HLR to check MS's QUALIFICATION FOR RECEIVING SERVICES,
6. Transaction 6 : VLR2 sends a service Profile Request (INVOKE) to HLR to obtain the service profile
for the roaming MS.
PCN/PSTN Call Control Using ISUP:
Typical message flow for type 2A with SS7 land-to-mobile call setup and release involving a tandem
Switch:
When MIN is dialed, end office(EO) notices that the number is for wireless service. Suppose that EO
has HLR query capability.
EO sends a query message to obtain MS’s TLDN (Temporary Local Directory Number). Messages
&xchanged among switches, VLR and HLR are TCAP messages.

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 Signaling path from PSTNino

YV-@-—@
Step 6

s Fig. 1.36 : PCN/PSTN Call Control using ISUP

= ic 1: After the MS's, TLDN
is obtained. eo SENDS AN INITIAL
Address Message(LAM) to the pe
“'gnaling for trunk setup.
Tesponse from Msc within timeout When LAM is Sent, IAM timer is set at the EO. EO excepts
period, toms
4

* Oneof following th
ree €vents occurs:
(@) MS is connected
with another call:
* This situation is refe
rred to as call collision
Call is Processed with
call forwarding or T cal
l
(b) MS is idle:
MSC send address complete Mes
sage (ACM) to Eo, Message inform
indications, and end-to-en s EO of Ms infjenatae
d protocol requirements, 0 [a
¢ When the EO receiyes the
ACM, the 1AM timer is Stoppe
d
(c) MS does not answer the Page:
MSC returns REL message to EO,
Step 4: When MS answers call, An
answer message (ANM) is sent from
MSC to EO
Call is established through trunk path, to EO,
Step 5: EO sends a Release Message (REL) to indicate that
specified trunk is being released f off
connection. Trunk is not set to idle is bein ;
is EO until a RELEASE Complete Messag
e(RLC) eisr
Step 6: When MSC receives REL from Eo, messa :
relies with a RLC. After RLC is sent, EO a tandem ™
for 0.5 to 1 sec, before it seizes the released trunk for the next call.
sent,

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Wireless and Mobile Network 1.41 Basics of PCS and GSM

GSM Network Signaling:

e GSMsignaling defines the communications between the mobile and the network. Signaling has to be
carried through the network and across the air- interface to the mobile.
GSM Protocol Interfaces:
Databases:
VLR (Visitor Location Register)
pwn p

HLR (Home Location Register)

AUC (Authentication Center)
EIR (Equipment Identity Register):Used to maintain a list of legitimate, fraudulent. or faulty
mobile stations also works with HLR to block calls from illegitimate MS.
Switches:
1. MSC (Mobile Switching Center)
2. GMSC (Gateway MSC)
3. SSP (Service Switching Point)
Radio Systems:
1, BSC (Base Station Controller)
2. BTS (Base Transceiver Station)
3. MS (Mobile Station)
Databases D
VL Sip Ler,
i ZL
Switches
Cc B F

Radio systems

A-bis ee
5

BTS BTS BTS | | MS

Fig. 1.37 : GSM Protocol Interfaces

GSM MAP Protocol Hierarchy:
Osi GSM MAP
Service User Mobile
Application Service Application
Presentation provider Part (MAP)
Session
Transport Transaction Capabilites
Application Part(TCAP)

Network Signaling Connection ae

Control Part (SCCP)

~~ Datalink \ Message Transfer Part (MTP)

Protocall Nieto Y wu

Fig. 1.38 : GSM MAP Protocol Hierarchy

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 Tah
Ta
Neitg ee
en ny
aT ae AVC a
umbe) ‘
WER sere swatuel

00000110
00000111

00001000

* The originati On nod

destination. In this © does no
t have enough knowledge to identify the a Ctual a
Case, the SCCP translates the actual desti
nation address by on c

Dial
__MAP Service User
Service Request

pnfirm)

oe
_—
a ae ia

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("i=
Wireless and Mobile Network 1.43 Basics of PCS and GSM

The Parameters of a Service Primitive Type:

M (Mandatory)
0 (Service Provider Option)
U (Service User Option)
Cc (Conditional)
Two Type of MAP Services;
1. Specific MAP service
2. Mobility Services
Operation and maintenance services
Call-handling service
Supplementary service
Short message service management service
Common MAP Services:
+ MAP-OPEN : Used to establish a MAP dialogue
¢ MAP-CLOSE:; Used tocleara MAP dialogue
MAP-DELIMITER : Used to explicitly request the TCAP to transfer the MAP protocol data units.
* MAP-U-ABORT : Used by the service user to abort a dialogue
MAP-P-ABORT : Used by the service provider to abort a dialogue
MAP-NOTICE : Used by the service provider to inform the service user of protocol problems such as
abnormal event detected by the peer and response rejected by the peer.
MAP Protocol Machine:
DSM (Dialogue State Machine):
* Co-ordinates the Service State Machines (SSMs)
* For every MAP dialogue, an instance of DSM in created to handle the dialogue.
RSM (Requesting Service State Machine):
Handles a MAP-specific service requested.
PSM (Performing Service State Machine):
Handles a MAP service performed
Load Control:
Monitors the traffic generated by the service activities. If overload situation in detected, low priority
MAP operations may be ignored.
Handoff, mobility management, short message services, subscriber -controlled inputs.
MAP_PROVIDER (MAPPM)

| PSM ,
marries
i MAP_USER}—1-4 MAP| DSM
4
bee _
OC cia
PSM tg CARS

Fig. 1.40 : MAP protocol machine

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 a

i . FE =

res 2
ind) 4.MAMAP_OPEN(ng,
P ry)
MAP_Deso
5 BEGING
a,TeINVOKE ind)
iiMmret
‘ 5.MAP_Opey,
MAP_ Servint
, CONTINUE (req) MAP_DELIMiTe
* TC-RESULT_(req)
R
aa MAP Sen font 7, TC_CONTINUE (Ind)
MAP_DELIM ER nd _TC_RESULT-L (ind) ;
- MAP Service
—
2 (req
MAP_DELIMITER (req] 9. TC_CONTIN
UE (req)
gr
nh
. TC_CONTINUE(Ind)
Er 11. MAP_Service 9
MA
P_DELIMITER
13, TC_END(req) 12. MAP -Service2
Se
5.MMAP
AP_TcL
SERvice 14. TC_END(ind) TC_RESULT _L(req) MAP_CLOSE oq
ose man «—_Teo
1C-RESULT_L(Ind) *

Step 1. Fig. 1.41: Exam le of MAP

: e dialogue

Service User

to the DSM.
The DSM continues to
primitive is encoy

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Wireless and Mobile Network 1.45 Basics
of PCS and GSM
¢ The TC-* Request primitives will be delivered by the TCAP and the lower layer protocols of S$7 to the
peer MAP PM;the primitives are now of type Indication.
Step 3:

4.MAP_OPEN(Ind)
MAP_Service | (|nd)
MAP_DELIMITER (Inq)
* When the MAP PM of the dialogue responder receives the TC-BEGIN Indication, a DSM is invoked.
If
the DSM identifies any error from the received TC-BEGIN Indication, a TC-U-ABORT Request
is sent
back to the dialogue initiator to terminate the dialogue.
* The DSM also checks if the system is overloaded. The DSM issues the MAP-OPE
N Indication primitive
to its MAP service user. The DSM then encounters the TC-INVOKE Indication primitive
, which results
in the creation of a PSM.
* The PSM sends a MAP-NOTICE to its MAP service user. No error occurs,
the PSM issues a MAP- Service
1 Indication primitive to be passed to its service user, and the control is passed
back to the DSM.
* After the DSM has processed all received components, it informs its MAP
service user by the MAP-
DELIMITER Indication primitive.
Step 4:

Service Provider TCAP [Service User| [Service Provider

5.MAP_OPEN(rsp)
MAP_Service(rsp)
MAP_DELIMITER (req)
* The MAP service user processes the Indication primitives received from
the MAP service provider,
and returns the results with the MAP-OPEN and the MAP-Service 1 Respons
e primitives, followed by
the MAP-DELIMITER Request primitive.
Step 5:

[Service Provider| | TCAP | |Service User [Service Provider|

6. TC_CONTINUE (req)
TC_RESULT_(req)

* When the MAP service provider receives the MAP-OPEN Respo

nse primitive, the DSM first checks if
the response is negative. If so it generates a MAP _Refuse_PD
U(protocol data unit) to be delivered by
the Indication primitive TC-END. Assuming that the response is positive, a MAP_Accept_PDUis
generated.
* The DSM proceeds to receive the MAP-Service1 Response
primitive and passes the control to the PSM.
* The PSM checks if any user error is present. The
PSM issues a TC-RESULT-L Request primitive and
Passes the control back to the DSM.
* The DSM continues to process the Specific service
primitives until the MAP-DELIMITER Request
Primitive is encountere d. The DSM issues a TC-CONTINUE Request primitive with the
MAP_Accept_PDU
Step6:
[Bevice Used] Service Provider sae | =a
7. TC_CONTINUE (ind)
TC_RESULT-L (ind)

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 1,46
Re
received by the MAP sery:Ce . a
* The Te-CONTINUE/TC-RESULT. taleation tives are p -.
the dialogue initiator, When
the DSM rece
PSih e TC-CONTINUE, It per forms tests, a*8 4%)
deg
step4,
* Te accepts the dialogue and passes handle the speci fic service Vice ».,
Se iathegl
MAPib
-Service 1 confirm p rimiti ay
The RSM maps the TC-RESULT-L para ve
p ty3
=
the DSM. After a il components have
been process ed, the DSM inf
Orms
Service user,
Step 8:

* The Map Service user of the dialog

ue initiator handles the confirm priimitives and
New requests, mi Possibly 4
MAP Service Primit
ives

D interface

VLR

—>» MAP_SEND_ Routin

INFORMATION
g

MAP_PORV) -ROMING_NUMBER
MAP_PORUIDE_ROMIN G_
(a
NUMBER_ack
RAELEND

t+
_ROUTIN
G INFORMAT
ION ack

“Retrieval of
Fig. 1,42, Retr
routing Info
rmation>
ieval ofroutin
.
g ioninformat
ned MAP SEN EA
S=ND-ROUDTRIONUGTIINNG INFORMa
FORMaTionT PaINra Parameters
me ters
Invoke ID
M |__ mi) —} Response)
CUG interlock ae
Number of Forwardin ee : el
S
Network Signal Info e
ie
IMSI oe
Forwarding Data
a
Provider Error
| ae esl
*
7
t
Mer es number generated by th a
e MA P se Tice
in the MAP service us er-provi
der interface.
user to identi
bie fy the Corresponding
a “— service P
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 1.47 Baofsi
PCS cs
and GSM

: The mobile station ISDN number,

cuG (Closed User Group) Interlock:
+ Agroup of users (eg. employees of a company) with specific network services, Possible to limit
The
incoming/outgoing calls inside the group,
cuG Outgoing Access:
« Represents the outgoing access of a closed user group.
Number of Forwarding:
+ Counts the number of times the call has been forwarded.
Network Signal Info:
« Provides external signal information, Signaling proto
col between the GSM network and the PSTN.
IMSi( International Mobile Subscriber Identity):
« Used to identify the called Ms,
MSRN(Mobile Subscriber Roaming Number);
« Therouting number that identifies the current location
of the called MS.
Forwarding Data:
* Used to invoke the call-forwarding service,
User Error:
* Sent by the responder when an error is detected.
Table 1.4: MAP PROVIDE ROAMING_NUMBER Parameters
Parameter Name Request Indication | Response Confirm
Invoke ID M M(=) M(=) M(=)
IMSI M M(=)
MSC Number
|
M M(=) |
LMSI C C(=)
GSM Bearer Capability Cc C(=)
MSRN c C(=
User Error c C{=
Provider Error 0. _..|
MAP_PROVIDE_ROAMIN G_NUMBER Parameters:
MSC Number:
* The ISDN number of the MSC where the called MS resides,
LMSI(Local Mobile Station Identity):
. Used by the VLR for internal data management of the called MS.
GSM Bearer Capability:
* Included if the connection is for nonspeech services such
as short message services.
User Error;
* Sent when an error is detected.

welds Rel tytoysts

What are the differences between cellular and low-tier PCS or cordless teleph
ony?
What are the two major parts of a typical PCS network architecture?
What are the benefits of digital PCS systems?
What is the major difference between design for licensed and for
unlicensed low-tier PCS
Systems?
What are the differences between the second generation
mobile technology and third generation
mobile technology?
6. What is handoff? What is roaming?
How do you perform handoff during roaming?
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 7 Describe the main steps of inter-BS re.
8. Describe the intersystem handoff procedu
9. Why is path minimization handoff procedure.
10. Draw the Message flow necessary? call
11. Describe the basic PCS of an MS originated call p procedure.
location update procedure.
as a common channel signa lling protocol? What are main «
12. Why is SS7 classified
SS7 architecture? Describe them.
1B At which
level of the ss7 e place? When do we
protocol stack does
Wrpollity management? the aiaaiten nea, |
Purposes of can we Modify
14. What are the 18-44 SOXH8LG
and the component t
a
15. What are the
the package types in a TCAP message)
Isyp messages usually used for? typ implement the
Procedure using Can we Is-41 pe.
ISup?
16. Which layers ne responsible for ISUP and
Bis Tat
°
outing? Why or not, TCAP routing? Do we need
17. Write features GTT for ISU,
of
18. State the Various GSM
services offered
19. Draw and ©xplain by GSM
Gsm System architecture.system.
20. Explain Gsm
radio subsystem,
21. List Gs air interface
22. Explain channel Specification,
types useq in GSM
23. Explain Authentication in brief,
24. Describe call processing Process in GSM.
25. in GSM system with
What is Gsm Location suitable diagram.
26. update? When it is
Describe Step procedure occurred?
27. Write an algorithm for VLR failure Restoration.
for cal] termination
28. Write an algorithm of VLR overflow.
for Registration of
29. Explain Mobility VLR overflow.
Database of HLR
30. Explain HLR failure and VLR
31. Describe Step
Restoration.
procedure for VLR
32. Describe situation failure Restoration.
when GSM Location
33. Describe the
mobility of the database update is Performed.
34. Describe the wrt HLR and VLR.
Stepwise procedure
35. Write an algorithm for HLR Failure restoration.
for call Origination
36. Write an algorithm of VLR Overflow,
for call termination
37. Describe the
registration process of VLR overflow,
of mobile system
when it j
38. Describe Gsm Lo
cation update Proced
39. With neat diag ure,
ram describe Step
40. Write algorithm s for VLR failure
for call termination of restoration
VL R Procedure.
41. Describe HLR rest ov er flow.
oration procedure.
42. What is the EIR used
for in GSM networks?
43. Which networ
k entities use
44. What are the GSM MAP to comm
four Categories a se unicate With ea
rv ic e Pr im ch other?
45. What are the parts of it iv e
the MAP Protocol machin can be?
46. Why are there e?
several instances
of RSMs and PSMs
47. How is the routing in in a MAP py?
formation retrieved using
48. Does GSM MA Gs M MAP?
P use the same Ss7
Signaling mechanism
as IS-41?

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 f@ Describe function of the given component of the GPRS architecture.
8) Describe characteristics of the given IEEE protocol standard for wireless communication networks.
f@) Explain architecture of the given IEEE 802.11 protocol standard.
(| Compare the performance of given wireless network technologies based on given criteria.
f@] State the procedure of scheduled maintenance of the given system.

ning Objectives... : uke sil

To understand Basic Concepts of GPRS and its Architecture

To learn Mobility Management and Routing in GPRS
@

To learn WLAN, RFID, Bluetooth Technology, Wi-Max and Wi-Fi

To study Mobile IP
®

« The General Packet Radio Service (GPRS) is a new bearer service for
GSM that greatly improves and
simplifies wireless access to packet data networks, e.g, to the Internet,
:
* It applies a packet radio principle to transfer user data packets
in an efficient way between mobile
stations and external packet data networks.
* The impressive growth of cellular mobile telephony as well
as thenumber of internet users promises
an exciting potential for a market that combines both cellular (mobile
) service and data service,
* These services when combined is known as cellular wireless
data services which can provide high-
performance wireless internet access to the users.
* Existing cellular data services do not fulfill the needs
of users and providers, From the user's point of
view, existing cellular data services lags in-data rates are too slow,
connection set up takes too long
and is rather complicated, service is too expensive for most
users,
* From the technical point of view, current wireless
data services are based on circuit switched radio
transmission. At the air interface, a complete traffic channel is
allocated for a Single user for the
entire call period.
* Incase of bursty traffic (eg. Internet traffic), this result
in highly inefficient resource utilization, It is
obvious that for bursty traffic, packet switched bearer
services result in a much better utilization of
the traffic channels.

[2.1]
 2.2 GPRS and Mobile Pate Conn | "
Wireless and Mobile Network
immediately att
° This is because a channel will only be allocated when needed and will be released
can share one physical channul
the transmission of the packets. With this principle, multiple users
(statistical multiplexing).
dat a technologies have been developed,
e Inorder to address these inefficiencies, two cellular packet
far:
1. Cellular digital packet data (CDPD) (for AMPS, IS-95,1S-136) and
2. General Packet Radio Service (GPRS). a
for GSM, but can also be integrated within IS-136.GPRS is q
* GPRS was originally developed
access to packet data Networks
bearer service for GSM that greatly improves and simplifies wireless
é.g., to the Internet. 2 ;
¢ It applies a packet radio principle to transfer user data packets in an efficient way Detweeniamy
mobile stations and external packet data networks. Packets can be directly routed from the GPRs
mobile stations to packet switched networks.
Intranets)
* Networks based on the Internet protocol (IP)(eg., the global Internet or private/corporate
and X.25 networks are supported in the current version of GPRS.

access. Fig 2.1 shows architecture of GPRS.

Circuit
switched ! a

weeeee Signalling --- Circuit switched GSM ——— Packet switched data and singalling
Fig. 2.1 (a) : GPRS Architecture
¢ GPRS architecture works on the same procedure like GSM network, but, has additional entities thét:
allow packet data transmission.
e idi
This data network overlaps a second generation GSM network providing pack
§ packet data transp
nsport at @
rates from 9.6 to 171 kbps.
e Along with the packet data transport the GSM network accommodates multiple users to share the
same air interface resources concurrently. GPRS usually attem ts gs e twork
reuse the existing GSM n
to a
:
y P
elements as much as possible.
4

Zz eee
 — “2, LL. wo OU ™@ 6 i hUTl lO ee ee

Wireless and Mobile Network 2.3 GPRS and Mobile Data Communication

BTS.

— I BTS Ly BSC
[HL
15

_j | Grinterface <-> Gc interface

i we .

' pee 4
MS 1 Z ;
ed 1
I I
I !
1 ! ! I
i| FieBIS
v a ; !
1 I I
—
1 I I !
!j S 8TS zi I ! !
= \ I! I I

Um interface
' —— oy , ’ if
Abis interface Gb interface Gn Interface Gi interface
Base station subsystem GPRS network
Fig. 2.1 (b): GPRS Architecture with Network Nodes
* There are new entities called GPRS that supports nodes (GSN) which are responsible for delivery and
routing of data packets between mobile stations and external packets networks.
* There are two types of GSNs namely, Serving GPRS Support Node (SGNS) and Gateway GPRS Support
Node (GGNS).
* There is also a new database called GPRS register which is located with HLR. It stores routing
information's and maps the IMSI to a PDN (Packet Data Network) address.
GPRS Mobile Stations:
*
New Mobile Stations (MS) are required to use GPRS services because existing GSM phones do not
handle the enhanced air interface or packet data.
* These mobile stations are backward compatible for making voice calls using GSM,
GPRS Base Station Subsystem:
*« Each BSC requires the installation of one or more Packet Control Units (PCUs) and a software
upgrade.
e The PCU provides a physical and logical data interface to the Base Station Subsystem (BSS) for packet
data traffic. The BTS can also require a software upgrade but typically does not require hardware
enhancements.
© When either voice or data traffic is originated at the subscriber mobile, it is transported over the air
interface to the BTS, and from the BTS to the BSC in the same way as a standard GSM call.
¢ However, at the output of the BSC, the traffic is separated; voice is sent to the Mobile Switching
Center (MSC) per standard GSM, and data is sent to a new device called the SGSN via the PCU over a
Frame Relay interface.
GPRS Support Nodes (GSN):
* AGSN isa network node which supports the use of GPRS in the GSM core network. All GSNs should
have a GN interface and support the GPRS tunneling protocol. There are two key variants of the GSN,
namely Gateway and Serving GPRS support node.
* Twonewcomponents are added namely, Called Gateway GPRS Support Nodes (GGSNs) and Serving
GPRS Support Node (SGSN). .
1, Gateway GPRS Support Node (GGSN):
* The Gateway GPRS Support Node acts as an interface and a router to external networks, It contains
routing information for GPRS mobiles, which is used to tunnel packets through the IP based interna}
backbone to the correct Serving GPRS Support Node.
 el > eo re i a i

r
Wiranc
el Mobi
e les
Netw
sork Se
eS GPRS and Mobile Data Commun,
= | =

orks antl |
The GGSN also collects charging information con nected to the use of the external data netw
=

can act as a packet filter for incoming traffic.

2. Serving GPRS Support Node (SGSN):
* SGSN support:
\ (i) Authentication of GPRS mobiles.
(ii) Registration of mobiles in the network, |
(iil) Mobility Management, and
(lv) Collecting information on charging for the use of the air interface.
* At higher speeds GPRS is designed to provi t higher speeds than those
de packet-data services a
d available with standard GSM circuit switched data services, |
: * In theory GPRS could provide speeds of upto 171 kbps over the air interface, ae a are
‘ never achieved in practical network. In fact, the practical maximum speed is a little over ps.

veeme GPRS Services

¢ The GPRS provides a set of GSM services for data transmission in packet mode within a PLMN, In
packet-switched mode, no permanent connection is established between the mobile and the external —
network during data transfer.
.3
* Instead, in circuit-switched mode, a connection is established during the transfer duration between
1
the calling entity and the called entity. In packet-switched mode, data is transferred in data Blocks, |
called packets. j
* When the transmission of packets is needed, a channel is allocated, but it is released immediately _
after, This method increases the network capacity. Indeed, several users can share a given channel,
since it is not allocated to a single user during an entire call period. q
* One of the main purposes of GPRS is to facilitate the interconnection between a mobile and the other
packet-switched networks, which opens the doors to the world of the Internet.
-
* With the introduction of packet mode, mobile telephony and Internet converge to
become mobile
Internet technology.
GPRS Data Services:
* Wide range of corporate and consumer applications are enable by GPRS services. GPRS Service
include all normal GSM services but in more efficient way.
* Italso support services like E-mail, Web browsing, Enhanced short message, Wireless imaging with
instant picture, Video service etc, E
| Document and Information Sharing
e Auseris likely to use either of the two modes of the GPRS
Tunneling mode.
1. Application Mode:
| * In this mode the user will be using the GPRS mobile
phone itself.
* The phone here acts as the end user devices,
application.
| * This browser allows browsing Ofte
eb
environment. Sites. Some GPRS device support mobile exec¥
2. Tunneling Mode
7)
s
3
&e

2a
&
8
5
ee ee $$$ 5S ee Se SaaS et eS Url lO eee

Wireless and Mobile Network 2.5 GPRS and Mobile Data Communication

¢ The end user device will be a large footprint device like laptop computer or small footprint
device
like PDA‘s. The MS will be connected to the device and used as a modem to access the wireless data
network.
GPRS Bearer Services:
* GPRS is a wireless extension of data networks. It can access to data networks, such as IP-based
networks (public internet, private intranet, and IPv4 and IPv6 protocols) and X.25 based networks.
1, GPRS upgrades GSM Data Services and Provides the following
Services :
2. Point-to-Point (PTP) Service: Internetworking with the Internet (IP protocols) and X.25
networks,
3. Point-to-Multipoint (PTM) Service: Point-to-multipoint multicast and point-to-multipoint
group
calls.
4, SMS Service: Bearer for SMS
5. Anonymous Service: Anonymous access to predefined services.
6. Future Enhancements: Flexible to add new functions, such as more capacity,
more users, new
accesses, new protocols, new radio networks.

GPRS Applications and Limitations

* In this section we will study GPRS applications and limitations,
Applications of GPRS:
1. Mobility : The ability to maintain constant voice and data communicatio
ns while on the move.
2. Immediacy : Allows subscribers to obtain connectivity when needed, regardless
of location and
without a lengthy login session.
3. Localization : Allows subscribers to obtain information relevant to
their current location,
* GPRS benefits the users in many ways, one of which is higher data rates
in turn of shorter access
times,
Limitations of GPRS:
1. Limited Cell Capacity for all users,
2. GPRS does impact a network's existing cell capacity. There are only limited
radio resources that
can be deployed for different uses,
3. Speeds much lower in reality,
4, Achieving the theoretical maximum GPRS data transmission speed of 172.2 kb
ps would require a
single user taking over all eight timeslots without any error protection,
5. Transit Delays GPRS packets are sent in all different directions to reach
the same destination,
This opens up the potential for one or some of those packets to be lost or corrup
ted during the
data transmission over the radio link.

GPRS Quality of Service (QoS)

Quality of Service (QoS) requirements of conventional mobile packet data applicat
ions are in
assorted forms,
* The QoS is a vital feature of GPRS services as there are different Qos support requirements for
assorted GPRS applications like real time multimedia, web browsing, and e-mail transfer,
* GPRS allows defining QoS profiles using the parameters like Service Precedence, Reliability, Delay
and Throughput.
* These parameters are described below:
 —— te mad _|_
a
—
Wireless and Mobile Network 2.6 GPRS and Mobile Data Communi
ation
1. Service Precedence:
The preference given to a service when compared to another service sAa'l
is ae ee Service Preced
cedence,
This level of priority is classified into three levels called as
High, Normal and Low.
When there is network congestion, the packets of low priority are discarded as compared
to high or
normal priority packets.
_2. Reliability:
This parameter signifies the transmission charac
teristics required by an SPP ica The reliability
classes are defined which guarantee certain maximum
values for the probability of loss, duplication,
mis-s equencing, and corruption of packet
s.
3. Delay:
The delay is defined as the end-to-end transfer time between two commu ; ;
nicating mobile stations oy
between a mobile station and the GI interface to an external packet data netwo
rk.
This includes all delays within the GPRS network, e.g., the delay for
Fesources and the transit delay in the GPRS backb
request and assignment of radio
one network.
Transfer delays outside the GPRS network, e.g., in extern
al transit networks, are not taken into
account,
4. Throughput:
The throughput specifies the maximum/peak bit rate and the mea
n bit rate.
Using these QoS classes, QoS profiles can be negotiated between the mobile user and the network for
each session, depending on the QoS demand and the available
resources.
The billing of the service is then based on the transmitted data volume,
the type of service, and the
chosen QoS profile.

PRS ARCHIT
AND EC
GPRS NETWO
TURK RE
NODE
GPRS architecture works on the same procedure like GSM network
, but, has additional entities that
allow packet data transmission. There are two key variants of
the GSN, namel y Gateway and Serving
GPRS support node.
vives) §=GPRS Network Nodes
* There are two Network Operation Nodes in GPRS:
1, GGSN:
e The first is the access point for an external data network and
is known as the gateway GPRS supp
node (GGSN). It contains the routing for GPRS-attached ort
users, With this information, GGSN
capable of delivering the packet data units (PDU) to the user’s is
current access p Oint.
e The location information can be obtained from the HLR via the oO
ptional Gc interface, The Gat
eway
ae eS

GPRS Support Node (GGSN) is a main component of the GPRS net

work,
* The GGSN is responsible for the interworking between the GPRS
network andexternal packet
switched networks, like the Internet and X.25networks.
eae

« From the external networks’ point of view, the GGSN

is a router to a sub-network, beca
use the GGSN
Pe

‘hides’ the GPRS infrastructure from the external

network, When the GGSN receives
—

to a specific user, it checks if the user is active. data addressed

* Ifit is, the GGSN forwards the data to the
SGSN serving the mobile user, but if the mobil
inactive, the data are discarded, On the e user Is
other han d, mobile-originated pack
network by the GGSN. ets are routed to the right

i
Wireless and Mobile Network
27 GPRS and Mobile Data Communication

To do all this, the GGsn keeps a record of active mobile users and
the SGSN the mobile users are
attached to. It allocates IP addresses to mobile users and last but not least, the GGSN is
responsible
for the billing.
. SGSN:
N

The second is the SGSN that serves the need of mobile users. When a user
is GPRS-attached, the
SGSN establishes a Mobility Management (MM) context containing information
pertaining to
routing, security and mobility, such as the identity of RA and LA where the MS is residing, and the
MS's MM states, etc.
The SGSN also ciphers Ps traffic, given that the base transceiver station (BTS, in GPRS, BTS
replaces
the BS in GSM,) is only responsible to cipher CS traffic
The Serving GPRS Support Node (SGSN) is a main component of the GPRS network
, which handles all
packet switched data within the network, e.g. the mobility management and authentication of the
users. The SGSN performs the same functions as the MSC for voice traffic.
The SGSN and the MSC are often co-located. The SGSN is connected to the BSC. The SGSN is the
service access point to the GPRS network for the
mobile user.
On the other side the SGSN relays the data between the SGSN and relevant GGSN (and vice versa).
The SGSN handles the protocol conversion from the IP used in the backbone network to the Sub-
Network-Dependent Convergence Protocol (SNDCP) and Logical Link Control (LLC) protocols used
between the SGSN and the mobile users, These protocols handle compression and ciphering.
The SGSN is also responsible for the authentication of GPRS mobiles, When the authentication is
successful, the SGSN handles the registration of the mobile to the GPRS network and takes care of its
mobility management.

Mobility Management in GPRS

The main task of the mobility management is to keep track of the user’s current location. The
MS
sends the location update message to the SGSN so that the network can be always aware of the
current location of the MS.
There are three states exist in the GPRS mobility management and the different location
information is available in each state. As a result, the different mobility management strategies are
applied in the different states.
State Model By Performing a GPRS attach, the MS gets into READY state and if the
MS does not
transmit any packet for a long period of time until the READY timer is expired, the MS will get into
STANDBY state.
It is possible to transmit data only if the MS is in READY state, thus the MS in STANDBY State
can
switch back to the READY state, if a PDU transmission occurs and in the same way, at READY state if
the GPRS detach is performed, the MS will be back into IDLE state and all PDP context will be deleted.
The GPRS state model is shown in Fig. 2.2.
In the STANDBY state, the MS sends the location update message seldom, so its location is not known
exactly and the paging is necessary for every downlink packet, resulting in a significant delivery
delay.
In ie READY state, the MS updates its location frequently. Consequently the MS’s location is known
precisely and no paging delay during delivery downlink packet. However this consumes much more
the uplink radio capacity and battery of the MS.
Location Update The State Model of GPRS Mobile Station deploys an appropriate location update
strategy in order to maintain the optimum network capacity as well as the MS battery drain.
Fig. 2.3 shows the fundamental concept of network cell-structure. Cell is the coverage area of the
radio transmission of base station (BS).
 —_ _l
eee a ss ee ete =@

le Data Communication :
Wireless and Mobile Network >.
2.8 a

GPRS attach
GPRS detach ;

STANDBy timer
expired

READY timer expired or

force to standby
Transmission of
a packet
STANDBY~

pete
? ‘
Fig. 2.2: State Model of GPRS Mobile Station
s in one LA, ~
Location Area (LA) and Routing Area (RA) consist of one or several cells and RA is alway

gS
When MS crosses LA border, a location update and RA update shall be done.
d. When the
In case MS moves within the same LA but crosses different RA, the RA update is neede
ds on the current state of
MS moves within the same LA and RA, cell update may be needed. It depen

ag
the MS.
is used in READY state. This |
The first case, that the MS updates the location every cell change,
is always known and packet data can be —
strategy ensures that the accurate location of the MS
delivered faster as no paging procedure is necessary.
d for cell updates. The
However the MS battery is drained more and uplink radio capacity is waste
MS moves to a
second case, used in STANDBY state, is that the MS updates the location only when the
|
new Routing Area (RA).
In this strategy, when data packet is sent to the MS, 10 paging is required iin order to find out the”
every
current location of the MS. Thus, uplink capacity will be wasted for paging response and
UlUD”™

downlink packet requires paging of the mobile delay.

ES eel

: Location Area |
Location Area —-
2
#2
et

Fig. 2.3: Cell, Routing Area and Location Area

RA Update Whenever the MS moves to a new RA, it sends a routing area update request including 4
routing area identity (RAI) of the old RA to its assigned SGSN. When the message arrives at the be
station subsystem (BSS), the BSS adds the cell identifier (CI) of the new cell. Based on the RAI and(
data, the SGSN can derived the new RAI.
Two different cases are possible; Intra-SGSN and Inter-SGSN routing area update.
Intra-SGSN Routing Area Update:
The MS has moved to an RA, assigned to the same SGSN as the old RA.
 ee a a ee

Wireless and Mobile Netw ork

29 GPRS and Mobile Cata Communication
* In this case, the SGSN knows already all necessary user profile, and
ea mobile subscriber iden
can assign a new packet
tity (P-TMS]) to the user without the
elements.
need to inform other network
Fig. 2.4 shows the message exchange
diagram of the IntraSGSN routing area
upda
ae

Cee
Aw Se ,
ae a ee eh mee nme es mi amb" fee

Routing arealupdate complete

_ —[P-TMSI]|(optional) i

Fig. 2.4: Intra-SGSN Routing Update

2. Inter-SGSN Routing Area Update:
* In this case, the MS has moved to an RA, assigned to
a different SGSN, thus, the new SGSN does not
have the user profile of the MS,
* The SGSN contacts the old SGSN and requests the PDP contex
t of the user. After receiving the PDP
context of the user, the new SGSN informs the involved
network elements, such as the GGSN about
the new PDP context of the user, and the HLR about the user’s new SGSN,
etc.
* Fig. 2.5 shows the message exchange diagram of the Inter-SGSN routing area
update.

MS BSS New SGSN Old SGSN GGSN HLR

Old RAI, oldjR-TMSI

GGSN address _

New GGSN address!

OK
~-

update database
¥

. OK

Fig, 2.5: Inter-SGSN Routing Area Update

* Cell Reselection When Mobile Station is in IDLE state, if the MS initiates attach procedure and the
currently camped-on cell already supports GPRS then no cell reselection is required.
* On the other hand, if the currently camped-on cell does not support GPRS then a reselection
procedure is required before execution of GPRS attach procedure.
 2.10
iion
GPAS and Mobile Data Communicat
Wireless and Mobile Network
rounding cells. If the
READY state, it conti nuo usl y monitors the sur
MS is in STANDBY and on procedure
formed. The cell reselecti
When
more suitable cell is found, a cell reselection procedure is per
in this case can be helpful to minimize the cell changes. new Cell mog:
o selea ct
the MS moves to a new locati on, the cell reselection is needed t
Besides, when
appropriate to the new location. ormed accordintp g
then the chan ges fro m one cell to another is perf
While MS is in dedicated mode,
the network-controlled handover procedures.
Paging of GPRS Mobile Station When the MS is in STAN DBY state, the network does not know the
ired to retrie
precise location of MS, thus paging procedure is requ ate cell Cn WES
ve the accur
MS has camped. paging
The MS in STANDBY state is paged by the SGSN before a downlink transfer to that MS. The
downl ink data to the
READY state to allow the SGSN to forward
procedure cause the MS to move to
radio resource. no response from the
procedure with a timer. If the SGSN receives
The SGSN supervises the paging gure demonstrates the
the SGSN wi ll repeat the paging. Fi
MS to the Paging Request message,
message exchange in the Paging proced ure.
BSS SGSN
MSs
PDP PDU

Paging Request

GPRS Paging Request

Any LLC Frame

Any LLC Frame +

Fig. 2.6: GPRS Paging Procedure

GPRS Data Routing

a mobile user, is one of the pivot requisites in
Data routing or routing of data packets to and fro from
the GPRS network.
into two areas namely, Data packet routing and Mobility
The requirement can be divided
management.
Data Packet Routing:
data network. The GGSN updates the
The important roles of GGSN involve synergy with the external
d by the SGSNs about the location of an MS.
location directory usin g routing information supplie
ulated over the GPRS backbone to thé
It routes the external data network protocol packet encaps
SGSN currently serving the MS.
appropriate data network and
It also decapsulates and forwards external data network packets to the
collects charging data that is forwarded toa charging gateway (CG).
There are three important routing schemes:
at the 7
1. Mobile-Originated Message : This path begins at the GPRS mobile device and ends
at the host
Network-initiated message when the MS is in its home network. This path begins
ends at the GPRS mobile device.
 oo S°RS enc Mable Dew Gommuminstior

Sea MS Roums tp enother GPRS Network: This path bapins et

= ~ WOCK End ends st the GPRS mmcbilie device The GPRS network encepsaletes
Sata mister FECOCOS Emi ts own encepsuletion protocel called the GES tarmmeliing
eee nit GU? ensures security in the backers metecck and Sinplities the routing
on and che delivery of date oer che GERS nenwmk
a

== aS Management: The operation af the GEES is partly inBepenieat of the GON ae

np
>
sane Poocedames share the neteurk elements with current GSN Sasi ae eee
Se pe ee
nn to make optim as
use of free =
GSM resources {sucha as unallocated times
=
tets.

2. GSM uses = two-siete mode

l either ids cracsps.
Active Stete
. waka
Ti 28At —~S-,
Transmitted esbetwee an
—
WS = and sh. GPRS ee network7 only= whe
n ~ S
n the MS isEs,in the acti~ve siete In
tt active state, the SCSW knows tie co] loca
tion of the MS.
© *ra
Oke
f. ---,TWenemssi7
on to an esacMS ti is v
ss
inite ieted =>%OF pSCke:
le =
Paeme =
to notify -
the=
MS of an inc
s.
oming
=
Gate packet The dete transmission procesds iumadi
stely after packet paging throagh the channel
indicated by the paging Mmessape
. T-aa oo, Powe ofOf the paging mes
32-355... <
sage is= to simp
=
lify
oe
the process of oe receivin
ee
g packets. The 4S Betens oo
Muy the paging messapes instead Of to all
the Gate packets in the downlink Channels. This red
aces
3
* When an MS has 2 packet 7to transmit
Semeat, ;Ht mamst access the uplink channel
packet data network where services resi fi2_ the channel to the
de) The uplink channel is shared by a num
use is alloca ber of MSs and ite
byte
2 Ess.
d
* ihe MS requests use of the channel
in a random access message The BSS
lannel to the MS and sends an allocates an umed
access grant
message in reply to the random access
Standby State: message:
. In the standby state, only the routing area of the
MS is known. (The routing ares
more cells withina GSM location area). can consist of one or
. When the SCN sends a packet to an
MS that isin the standby state, the MS mus
Rie SGSN knows the routing area of t be paged Because
the MS, a packet paging message is sent to the
. On receiving the packet paging message, routing area.
the MS relays its cell location to the SGSN
active state. to establish the
Idle State:
* In the idle state, the MS does not havea logical
GPRS context activated or
Data Network (PSPDN) addresses allocated. any Packet-Switched Public

send messages to the MS from external data networks.

Routing Updates:
* When an MS that is in an activora e standby state moves from one routing area
to another within
the service area of one SGSN, it must perform a routing update.
* The routing area information in the SGSN is updated, and
the success of the procedure isindicated
in the response message.
* Acell-based routing update procedure is invoked
when an active MS enters a new cell. The MS sends
a short message containing the identity of the MS and its new :
location through GPRS channels to its
current SGSN. This procedure is used only when the MS is in the active
state.
 ee
EO

GPRS and Mobile Data Communica

mn ttlon
Wireless and Mobile Network 2.12

* The inter-SGSN routing update is the most complicated routing © pdate. The MS changes from on,
SGSN area to another, and it must establish anew connection to a new SGSN.
¢ This means creating a new logical link context between the MS and the new SGSN and informing th,
GGSN about the new location of the MS.

Logical Channels in GPRS

On top of the physical channels, a series of logical channels are defined to perform a multiplicity of
system information, channg|
synchronization,
functions, €.g., signaling, broadcast of general

assignment, paging, or payload transport.

* Table 2.1 lists the packet data logical channels defined in GPRS. As with conventional GSM, they cay
(Control) Channels.
be divided into two categories namely, Traffic Channels and Signaling
Table 2.1 = ———

Packet data traffic channel PDTCH | Data traffic MS <P BSS

Packet broadcast control channel PBCCH Broadcast control MS<4BSS
Packet common control channel| PRACH | Random access MSP BSS
PAGCH | Access grant MS 4BSS
(PCCCH) MS <4BSS
PPCH Paging
Notification MSPBSS
PNCH
Associated Control
PACCH MS<PBSS
Packet dedicated control channels
PTCCH Timing advance control MS<4PBSS
user data. It is assigned to one
The Packet Data Traffic Channel (PDTCH) is employed for transfer of
. One mobile station can
MS (or in the case of PTM (point to Multipoint) to multiple mobile stations)
use several PDTCHs simultaneously.
point-to-multipoint signaling
° The Packet Broadcast Control Channel (PBCCH) is a unidirectional
specific information about the
channel from the BSS to the MS. It is used by the BSS to broadcast
s of a cell.
organization of the GPRS radio network to all GPRS mobile station
ast important system
e Besides system information about GPRS, the PBCCH should also broadc
information about circuit switched services, so that a GSM/GPRS mobile arate does not need to

listen to the Broadcast Control Channel (BCCH).

nal point-to multipoint signaling
so The Packet Common Control Channel (PCCCH) is a bidirectio
e.g., for allocation
channel that transports signaling information for network access management,
of radio resources and paging. It consists of four sub-channels:
one or more
(i) The Packet Common Control Channel (PCCCH) is used by the mobile to request
PDTCH.
PDTCH toa mobile
(ii) The Packet Access Grant Channel (PAGCH) is used to allocate one or more
station.
(iii) The Packet Paging Channel (PPCH) is used by the BSS to find out the location of a mobile station
(paging) prior to downlink packet transmission.
(iv) The Packet Notification Channel (PNCH) is used to inform a mobile station of incoming P™
messages (multicast or group call).
The dedicated control channel is a bidirectional point-to -point signaling channel. It contains the
channels PACCH and PTCCH.
 =——— _ ————E—— a =e eee : i. EE
es

SOS Ne Ore Lane 2.13 GPRS and Mobile Data Communication

The Packet Associated Control Channel (PACCH) is always allocated in combination
with one or more
PDTCH that are assigned to one mobile
station.
* It transports Signaling information related to
onespecific mobile station (e.g., power control
information). The Packet Timing Advance Control Channel
(PTCCH) is used for adaptive frame
synchronization.
The coordination between circuit switched and packet
switched logical channels is important. If the
PCCCII is not available in a cell, a mobile station can use the Common Control
Channel (CCCH) of
conventional GSM to initiate the packet
transfer.
* Moreover. if the PI3CCH is not available, it will listen to the Broadcast Control Channel (BCCH) ee get
informed about the radio networ
k.
MS Bss

Packet channel
request

Packet immediate
assignments

Packet resource
request

Packet resource
assignments

(Optional)

Fig. 2.7: Uplink channel allocation (mobile originated packet transfer)

* Fig. 2.7 above shows the principle of the uplink channel allocation (mobile originated packet
transfer),
* A mobile station requests radio resources for uplink transfer by sending a “packet channel request”
on the PRACH or RACH. The network answers on the PAGCH or AGCH, respectively. It tells the mobile
station which PDCHs it may use.
* Aso-called Uplink State Flag (USF) is transmitted in the downlink to tell the mobile station whether
or not the uplink channel is free. j

IEEE 802.11 WLAN Standards

* The IEEE 802.11 committee is responsible for ‘Wireless Local Area Network (WLAN)’ standards.
WLANS include IEEE 802.11a (WiFi 5), IEEE 802.11b (WiFi), IEEE 802.11g and IEEE 802.11n.
The objective of the IEEE 802.11 standard was to define a Medium Access Control (MAC) sublayer,
MAC management protocols and services, and three PHYs for wireless connectivity of fixed,
es within a local area.
maid som iin iataeeeat to support a network where most decision making is distributed
to mobile stations.
— eee a Z ~
; GPRS and Mobile —
Wireless and Mobile Network
2
all of th e Vv WLAN equi ip
toler ant of faults in
e I tis
has Ti lad Vi an tagg Ss "
severa
hitecture
: itectu
and eliminates possible bottlenecks a centralized ap CHatet
~~ MAC Layer

Physical layer
PHY Convergence -
Procedure (PCLP)}
Management

= PHY Medium > ~ 2

pendent (PMG) ules
WLAN
Fig. 2.8: OSI Model for IEEE 802.11
802.11 Physical Layer:
* The physical layer provides three levels of functionality. These include: :
1, Frame exchange between the MAC and PHY under the control of the Physical Layer Convergencs
Procedure (PLCP) sublayer; ‘
2. Use of signal carrier and Spread Spectrum (SS) modulation to transmit data frames over ths
media under the control of the Physical Medium Dependent (PMD) sublayer; and i
3. Providing a carrier sense indication back to the MAC to verify activity on the media.
¢ The three physical layers are an IR baseband PHY, an FHSS radio in the 24 GHz band, and a Dsss
radio in the 2.4 GHz. All three physical layers support both 1 and 2 Mbps operations.
* Each of the physical layers is unique in terms of the modulation type, designed to coexist with each
other and operate with the MAC.
* The specifications for IEEE 802.11 meet the RF emissions guidelines of FCC, ETSI, and the Ministry of
Telecommunications.
« In DSSS PHY, two modulation schemes, differential binary phase shift keying (DBPSK) - for 1 Mbps
and differential quadrature phase shift keying (DQPSK) - for 2 Mbps are available.
e Ani1-bit Barker code is used for spreading.
e Each DSSS PHY channel occupies 22 MHz of bandwidth and allows for three non-interfering
channels spaced 25 MHz apart in the 2.4 GHz frequency band. Fourteen frequency channels are
defined for operation across the 2.4 GHz frequency band.
« In FHSS PHY, a set of hop sequences is defined for use in the 2.4 GHz frequency band.The channel
are evenly spaced across the band over a span of 83,5 MHz.
¢ In North America, the number of hop channels is 79. The hop channels occupy a bandwidth of iMHz
802.11a:
« It defines ‘Orthogonal Frequency Division Multiplexing (OFDM)’ scheme for modulation at the
physical layer.
« The idea is to divide a channel into sub-channels, thus using
multiple carriers. The modulation oa
each carrier is independent of each other.
* The OFDM PHY provides the capability to transmit PSDU frames
at multiple data rates up to 54 Mbps
fora WLAN where the transmission of multimedia content is a consideration.
« There are 48 data subcarriers and 4 carrier pilot
subcarriers for a total of 52 nonzero subcarriers
defined
in IEEE 802.11a. Each lower data rate bit stream is used
to modulate a separate subcarrie®
from one of the channels in the 5 GHz band.
802.11 Data Link Layer:
* The data link layer within 802.11 consists
of two sublayers namely, Logical Link Contr
Media Acces ol (LLC) and
s Control (MAC).
Wireless and Mobile Network 2,15 GPRS and Mobile Data Communication
The 802.11 uses the same 802,2 LLC and 48-bit addressing as the other 802 LAN, allowing for simple
bridging from wireless to IEEE wired networks, but the MAC is
unique to WLAN.
The sublayer above MAC is the LLC, where the
framing takes place. The LLC inserts certain
the frame such as the fields in
source address and destination address at the head end of the frame and error
handling bits at the end of the frame.
MAC sublayer defines how a user obtains a channel when he or she needs one. The 802.11 MAC is
similar in concept to 802.3, in that it is designed
to support multiple users on a shared medium
having the sender sense the medium before accessing by
it.
The 802.11 MAC scheme includes ‘Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) 7
to decide which station will access the media. ‘Collision detection’ cannot be used in WLANs.
In IEEE 802.11, the MAC sublayer is responsible for asynchronous data service (e.g., exchange of MAC
service data units (MSDUs), security service (confidentiality, authentication, access control
in
conjunction with layer management), and MSDU
ordering.
The MAC sublayer is also responsible for how a station joins an AP, switch to another AP.
802.11b-High Rate Dsss;
In September 1999 IEEE ratified the 802.11b high rate amendment to the standard, which added
two
higher speeds (5.5 and 11 Mbps) to 802.11.
To increase the data rate in 802.11b standard, advanced coding techniques are employed. Rather
than the two 11-bit Barker Sequences, 802.11b specifies complementary code keying
(CCK).
The S.5 Mbps rate uses CCK to encode 4 bits per carrier, while the 11 Mbps rate encodes
8 bits per
carrier. Both speeds use QPSK modulation and a signal at 1.375 Msps. This is how the
higher data
rates are obtained.
,
The key contribution of the 802.11b addition to the WLAN standard was
to standardize the physical
layer support to two new speeds, 5.5 and 11 Mbps.
To accomplish this, DSSS was selected as the sole physical layer
technique for the standard, since
frequency hopping cannot support the higher speeds without
violating current FCC regulations.
The implication is that the 802.11b system will interoperate
with 1 Mbps and 2 Mbps 802.11 DSSS
systems, but will not work with 1 Mbps and 2 Mbps FHSS systems,
To support very noisy environments as well as extended
ranges, 802.11b WLANs use dynamic rate
shifting, allowing data rates to be automatically adjusted to com pens
ate for the changing nature of
the radio channel. Ideally, users connect ata full11 Mbps rate,
However, when devices move beyond the optimal
range for 11 Mbps operation, or if substantial
interference is present, 802.11b devices will transmit at lower
speeds, falling back to 5.5,2, andi
Mbps.
Likewise, if a device moves back within the range of a higher-sp
eed transmission, the connection will
automatically speed up again.Rate shifting is a physical layer mechanis
m tr: ansparent to the user
and upper layers of the protocol stack.
802.11n:
In response to growing market demand for higher-performa
nce WLANs, the IEEE formed the task
group 802.11n.
The scope of this task group is to define modifications to
the physical and MAC layer to deliver a
minimum of 100 Mbps throughput at the MAC Service Access Point (SAP).
802.11n uses ‘Multi-input Multi-output (MIMO)’. MIMO divides a bit
stream into spatial streams, each
direct ed towards a different antenna. This ‘Space Division Multiplexi
ng (SDM)’ improves OFDM.
 *
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2.16 GPRS and Mobile Data Commury

Wireless and Mobile Network

The MIMO power saving mode mitigates to multipath only when it improves the overall performance
of WLAN.
The highest raw data rate will increase to 65Mbps from 54Mbps if the devices show compatibility .
with 802.1in standard.
‘Beam forming’ and ‘Diversity’ are two other techniques supported by 802.11n.
Beam forming focuses the beam directly towards the intended antennas at the receiver.
Diversity sums up the response of all antennas, takes the best subset, rejecting weak responses,
802,11n also supports aggregation. It bundles several frames and sends them together, reducing the
by 802.11g.
total time required. This aggregation enhances the mixed mode operation offered
Doubling the channel width from 20MHz to 40MHz increases data rates. However, it is used by

properly managing the needs of clients requiring high speeds and other clients which are connecteq
to the network.
The 802.11n specification was developed with previous standards in mind to ensure compatibility.
Table 2.2 : Primary IEEE 802,11 specifications and their comparisons =
_802141a | 802.11b__ 802.11 2]. e0zdin Say
Approval date July 1999 July 1999 June 2003 August 2006
Maximum data rate 54 Mbps 11 Mbps 54 Mbps 600 Mbps
Modulation OFDM DSSS orCCK | DSSS orCCK DSSS or CCK of
or OFDM OFDM

RF band 5 GHz 2.4 GHz 2.4 GHz 2.4 GHz or 5 GHz

Number of spatial streams 1 1 1 1,2,30r4
Channel width 20 MHz 20 MHz 20 MHz 20 MHz or 40 MHz

WLAN Applications
WLANs are designed to operate in Industrial, Scientific, and Medical (ISM) radio bands and
Unlicensed-National Information Infrastructure (U-NIJ) bands. These bands are license free.
Manufacturers have deployed WLANs for process and control applications.Retail applications have
expanded to include wireless point of sale (WPOS),
The health-care and education industry are also fast-growing markets for WLANs. WLANs provide
high-speed, reliable data communications in a building or campus environment as well as coverage
in rural areas. WLANs are simple to install
WLAN Applications
e Public
o Coffeeshop
o Airport
o Convention Centre
e Private
o Government
o Enterprise
o Manufacturing facility
o Home
« Semi-Public
o University
o Hospital
 J
Wireless and Mobile Network 2.17 GPRS and Mobile Data Communication

IEEE 802.11 WLAN Architecture

e Fig. 2.9 shows WLAN architecture.

Distribution system (DS)

Access point
(AP)

Basic service set (BSS)

single cell

Extended service set (ESS) multiple cells

Fig. 2.9: WLAN Architecture
STA: station
AP: access point
BSS: basic service set
ESS: extended service set
BSS: act as building blocks for formation of big wireless LANS
ESS: International collection of BSS
* When BSS's are interconnected the network becomes
one with infrastructure. 802.11 infrastructure
has several elements. Two or more BSS's are intercon
nected using a Distribution System or DS. This
concept of DS increases network coverage. Each BSS
becomes a component of an extended, larger
network. Entry to the DS is accomplished with the use of
Access Points (AP). An access point is a
station, thus addressa ble.
¢ So, data moves between the BSS and the DS with the help of
these access points.
* Creating large and complex networks using BSS's and
Ds's leads us to the next level of hierarchy, the
Extended Service Set or ESS. The beauty of the
ESS is the entire network looks like an independent
basic service set to the Logical Link Control Layer (LLC).
This means that Stations within the Ess can
communicate or even move between BSS's transparently to the LLC.
* While the implementation for the Ds is not specified, 802.11
does specify the services, which the DS
must support. Services are divided into two sections
namely, Station Services (SS) and Distribution
System Services (DSS).
* There are five services provided by the DSS
namely, Association, Reassociation, Disassociation,
Distribution, Integration.
* The first three services deal with station mobility. If a station
is moving within its own BSS or is not
moving, the stations mobility is termed No-transition.
* Ifa station moves between BSS's within the same ESS, its mobility
is termed BSS-transition. If the
Station moves between BSS's of differing ESS's it is ESS transition.
* Distribution and Integration are the remaining DSS's, Distribution
is simply getting the data from
the sender to the intended receiver.
peee _ Oh e,”©6=~ -
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ee
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Wireless and Mobile Network 2.18 GPRS and Mobile Data Commun,
a

* The message is sent to the local AP (input AP), then distributed through the DS oe AP (output
that the recipient is associated with. If the sender and receiver are in the same BSS, the input ang ous
AP's are the same. ;
* So the distribution service is logically invoked whether the data is going Pe ee ee OF not
Integration is when the output AP is a portal. Thus, 802.x LANs are integrated dee e t DS,
* Station services are Authentication, Deauthentication, Privacy and MAC Service Data Unit (MSDy)
Delivery.

IEEE 802.11
* In 1997, IEEE developed an international standard for WLANs, i.e. IEEE 802.11. Like ne IEEE 802
standards, this layer also focuses on the bottom two layers of the OSI model i.e. physical layer ang
data link layer.
* The objective of IEEE 802.11 was to define a medium access control (MAC) sublayer, Mac
management protocol and service and 3 physical layers for wireless connectivity of fixed, portable
and movable devices.
Comparison of Various IEEE 802.11x Standards (a/b/g/i/n etc):
Table 2.3
EEE 802.11 | IEEE802.1ia | IEEE 802.11b IEEE
Seema eee é i _ 802.11g
Applications WLAN WLAN WLAN
Modulation DSSS , FHSS OFDM DSSS orCCK | DSSSorCCK | DSSS orCCKor
or OFDM OFDM
Channel width 20 MHz 20 MHz 20 MHz 20 MHz 20 MHz or 40
MHz
Typical range 66 feet 75 feet 100 feet 150 feet 150 feet
Antenna 1x1 SISO ix1 SISO 1x1 SISO 1x1 SISO 4x4 MIMO
configuration (Single (Multiple
Input-Single | Input-Multiple
Output) Output)
e IEEE 802.11i is mainly designed for enhanced security purposes. It addresses two
main weaknesses
of wireless security networks which are encryption and authentication. Encryption is accomplished
by replacing WEP’s original PRNG RC4 also by stronger cipher that
performs three steps on every
block of data.
e The authentication and key management is accomplished by the IEEE 802.1x standard.

Radio Frequency Identification (RFID)

Radio frequency identification (RFID) is an automatic identification
method, relying on storing and
remotely retrieving data. The data is stored on and retrieved from RFID tags.
* The tag contains a transponder with a digital memory chip that is
given a unique electronic product
code. The data is written onto the memory and read from it.
* An RFID antenna packaged with a transceiver and decoder emits
a signal activating the RFID tag soit
can read and write data to the tag.
 ee e ee as et

Wireless and Mobile Network

2.19 GPRS and Mobile Data Communication
* When an RFID tag passes through the elec
tromagnetic zone, it detects the reader's acti
ree ane decodes the code ID of the tag and the vation signal.
data encoded in the tag’s integrated circuit (silicon
ip).
* In this way, an RFID tag is an information source. The data written onto it can
be retrieved whenever
needed or it can be transmitted to
different RFID readers.
¢ RFID is also called dedicated Short Range
Communication (DSRC).
¢ RFID components and their characte
ristics
RFID Features;
The following are the key features
of RFID:
* No Line-of-Sight: To read or write RFID tags does
n’t require line of sight.
* Robust: Because RFID systems do not need to be visible, they
can be encased within rugged material
protecting them from the environment in which they are being used. This means they can be used in
harsh fluid and chemical environments and rough handling
situations.
¢ Read Speed: Tags can be read from significant distances and can also be read very quickly. For
example, on a conveyor.
* Reading Multiple Items: A number of tagged items can be read at the same time with
in an RF field.
This cannot be done easily with visual identifiers.
* Security: Because tags can be enclosed, they are much more difficult to tamper with.
A number of
tag types now also come programmed with a unique identifier (serial identification) which is
guaranteed to be unique throughout the world.
¢ Programmability: Many tags are read/write capable, rather than read only. This means that
information can be written to the tag.
RFID Applications:
1, Automotive:
* Auto makers have added security and convenience to automobiles by using RFID technology for anti-
theft immobilizers and passive entry systems.
* Some auto manufacturers use RFID systems to move cars through an assembly line. At each
successive stage of production, the RFID tag tells the computers what the next step of the automated
assembly is.
2. Animal Tracking:
¢ Ranchers and livestock producers use RFID technology to meet export regulations and optimize
livestock value.
Wild animals are tracked in ecological studies, and many pets who are tagged are returned to their
owners.
Thus a tag can carry information as simple as a pet owner's name and address.
3. Assets Tracking:
Hospitals and pharmacies meet tough product accountability legislation with RFID; libraries limit
theft and keep books in circulation more efficiently.
; .
4, Contactless Commerce:
Blue-chip companies such as American Express, Exxon Mobile, and MasterCard use innovative form
factors enabled by RFID technology to strengthen brand loyalty and boost revenue per customer.
5. Supply chain:
eee Target, Best Buy, and other retailers have discovered that RFID technology can keep
inventories at the optimal level, reduce out of stock losses, limit shoplifting, and speed customers
through check-out lines.
 Me ANON oe ee Ol AE
GPRS and Mobile Data COMMUNICAton
Wireless and Mobile Network 2.20

6. Replacement for Bar Codes:

és
* RFID can serve a lot of advantages by replacing bar co fe
hnology is RFID eliminates the need of ling.
* One of the key differences between RFID and bar code
of-sight reading that bar coding depends on. anning. High frequency RFID
* Also, RFID scanning can be done at greater distances than
bar eae ae 90 ‘ee
systems (850-950 MHz, 2.4-2.5 GHz) offer transmission ranges
eless by defacement or smudging.
* Barcodes are fixed at the time of printing and can be rendered Ee aa having a laser printesig
Bar codes can be spoofed or easily defeated by any malicious 1n
their disposal.

Different Components of RFID and ication

Communicati Among 8 The

Components
Radio frequency identification (RFID) is an automatiticic i identification
i ion eeaeeigo
m ethod,10s
d, based on scene
storing ! and
: aoe 7 '
*
remotely retrieving data using devices called RFID tags or transpon
RFID.

Personal |P_
computer | =

—_,—_——_
RFID station

Fig. 2.10 ; RFID

© The following are the RFID components
1, Tags:
« An RFID tag is an object that can be incorporated into a product, animal, or person for the purpose of
identification using radio waves.
There are two types of tags namely, Passive tags and Active tag. Passive tags tag require no internal
power source, whereas active tags require a power source.
2. Transponder:
The transponder emits messages with an identification number that is retrieved from a database
and acted upon accordingly.
e The writable memory is used to transmit information among RFID readers in different locations.
3. The Interrogator:
An antenna packaged with a transceiver and decoder, emits a signal activating
the RFID tag so it can
read and write data to it.
* When an RFID tag passes through the electromagnetic zone, it detects the reader's activation signal.
4. Reader:
The reader decodes the data encoded in the tag circuit and
the data is passed to the host computer.
The application software on the host processes the data.

Risks and Benefits of Applying RFID in the Manufacturing Sect

* Radio Frequency Identification (RFID
or
), in particular passive RFID, has become
in industrial environments as a way to track increasingly common
and trace products, assets, and material flow.
 ee a ee
Wireless and Mobile Network 2.21 GPRS and Mobile Data Communication

Although the technology has been around for decades, recent advances in tag
design have driven
the cost down to levels that are helping fuel its acceptance in a wide variety of industries.
RFID interrogators, which capture and transfer information to and from tags (transponders) via
radio waves, are ideal for the most challenging industrial environments.
RFID, in contrast to traditional vision-based bar code reading systems, doesn't require a direct line of
sight to object identifiers.
As a result, High Frequency (HF) and Ultra High Frequency (UHF) RFID systems have made it possible
to track a wide range of products through the entire supply chain with more accuracy and
timeliness. .
Yet, despite the advantages, many industrial facilities are still hesitant to incorporate RFID into their
mix of automation solutions,
Improve the quality and transparency of data across the supply chain ;
Accurate data that is easily accessed makes it possible to solve a multitude of process inefficiencies.
The best way to implement a system that results in the highest reliability and availability is by using
the concept of ‘distributed data.”
In this context, distributed data refers to live data that is attached directly to the object and can be
modified automatically at process checkpoints,
When data is read from a tag, answers are provided to the questions: What? Why? Where? and
When? This is the very essence of RFID applications in industry.
. Make it easier to implement flexible manufacturing processes
Staying competitive often means producing more from the same production line. In order to make
production processes more flexible, there must also be flexibility in the content and delivery of data
to the various manufacturing cells.
The ability to accommodate and respond to a higher influx of constantly changing data is necessary.
RFID is used to reliably read and write data directly to a tag on an object in real-time. This capability
can be leveraged to make flexible manufacturing a reality.
. Increase the accuracy of and reduce the time spent taking inventories
Manually counting inventory is an extremely tedious; time consuming, inefficient, and inaccurate
method.
RFID can be used to reduce or eliminate the need for "hand-scanning,' resulting in immediate and
significant improvements in inventory tracking. These results directly impact the customer
experience and lead to increased sales.
. Reliable track and trace in challenging physical environments
Since RFID does away with the requirement that there be a direct line of sight to the object's
identifier, standard barcode labels (that can be ruined by extreme environmental conditions) can be
replaced with encapsulated RFID tags.
The need for reading and/or writing data to an object, when process conditions are extreme, can be
handled by attaching these durable RFID tags.
Conditions such as high humidity, drastic temperature swings, exposure to chemicals and paints,
extremely high temperatures, rough handling, and dirt wreak havoc on conventional paper barcode
labels,
Specially encapsulated RFID tags are designed to survive and perform reliably in even the most
challenging of environments.
Increase efficiency and cut down on rework
RFID can be particularly advantageous in closed loop systems where reusable transport mechanisms
are used.
 2 Ce Te eo

Wireless and Mobile GPRS and Mobile Datata C Ommunication

Network
aa i
* Real-time visibility y allows
all the observa
tion and close mo nitoring of products and processe‘ s so that
at have a major impact on quality can be
quick action can be taken and process improvements th
madeina timely manner with laser point precision.

Advantages of RFID
1. The RFID systems need low maintenance cost. : pe
2. As line of sight communications is not needed the RFID tags can be read/written in dirty
conditions also,
3. They can handle large amount of data. .
RFID is not affected by objects like paper, plastic, clothing, non- metallic materials that placed
*

between the antenna and RFID tag.

It provides secure and reliable data.
Hw

RFID supports multiple tag reads in shark interval of time.

Every RFID device has a unique serial number used for identification.
oN

The detection process is automatic.

yeeteee Disadvantages of RFID

1. RFID deals with assembly and inserting a computerized chip (RFID tag) in the device.
2. If RFID tags are installed in the metal and liquid products, it becomes tedious for the reader to
read the data. The liquid and metal surface reflect two radio waves, this makes two RFID tags
unreadable.
3. The life of active RFID's is battery dependent.
4. RFID systems are susceptible to virus.

Bluetooth Technology
Bluetooth is a wireless personal area network (WPAN) technology. It is based on IEEE 802.151
standards.
Bluetooth provides short-range, low-cost connectivity between portable devices. Bluetooth is limited
in range (<10 meters) and provides speeds of about 780 kbps. Thus, Bluetooth is used as a
replacement for cables and wired networks to form small Ad hoc private wireless LANs.
Definition of the Terms Used in Bluetooth:
1. Piconet:
e Acollection of devices connected via Bluetooth technology in an ad hoc fashion.
¢ A piconet starts with two connected devices, such as a PC and cellular phone, and may grow to eight
connected devices. All Bluetooth devices are peer units and have identical implementations.
¢ However, when establishing a piconet, one unit will act as a master for synchronization purposes:
and the other(s) as slave(s) for the duration of the piconet connection.
2. Scatternet:
¢ Two or more independent and non-synchronized piconets that communicate with each other.
A slave as well as a master unit in one piconet can establish this connection by becoming a slave i!"
other piconet.
yams ES ee ee eee ae

work
wireless and Mobile Net
unication
GPRS and Mobile Data Comm
3, Master Unit: =
e The device in the piconet whose clock
devices in the piconet,
and hopping sequence are used to synchronize all other
4, Slave Units:
e Alldevices in a piconet that are not the mas
ter (up to seven active units for each master).
5, MAC Address:
¢ A 3-bit medium access
control address used to distinguish between units participating in the
piconet.
6. Parked Units:
e Devices in a piconet which are time-synchronized bu:
t do o notnoth have MAC addresses ;
7, Sniff and Hold Mode:
pe that 3 synchronized to a piconet, and which have temporaril
y entered power-saving mode
in which device activity is reduced,

yey Frame Format in Bluetooth Technology

« Bluetooth packet can pect 1-slot (625 us) or 3-slot (1875 us) or 5-slot (3125 us).
ek ke Fiso Fig Fred Fuss
if Md] si M $2 M $3
625 us F, Frees Frag Frag
2 M $1 M $2

: Fie
38 $1

$1

3125 ps
1, One-slot symmetrical, 3. Three-slot symmetrical,
2. Three-slot asymmetrical,4. Five-solt asymmetrical
Fig. 2.11 (a): Bluetooth Packets
* Each packet consists of a 72 bit access code. The access code
is used for packet identification, Every
packet exchanged on the channel is preceded by its access code.
* Recipients on the piconet compare incoming signals with access code. If the two do not match, the
received packet is not considered valid and rest of its contents are ignored.
* The72 bit access code is derived from masteridentity.Thus, access code is also used for
synchronization and compensating for offset. The access code is robust and resistant to
interference,
72 bits 54 bits 2745 bits

Packet header Payload

Access Code

Traller
Preamble | Synchronization
(64) (4)
(4)
etooth
Fig, 2.11 (b): Packet Format in Blu
:
Header part of the packet is used by the Link Control (LC) logical channel. It has the following format
— =

Wireless and Mobile GPRS and Mobile Data COMMUNIcatigy,

Network 7
228
LSB 3
; ; B MSB
4 1

AM_ADDR TYPE FLOW | ARQN SEQN HEC

Fig. 2.12 ; Header format
AM_ADDR: Temporary address assigned to active members of the piconet, used on all ree
directions sent between v3 Thos
the master and the addressed slave. An all-zero AM_ADDR is used t,
broadcast to all slaves.
TYPE: Type of packet. There are 12 types of packets for each SCO and ACL physical links, and foy,
types of common control packets
for both.
FLOW: For flow control.
ARON: For ACK.
SEQN: Contains sequence number for packet ordering.
HEC: Header error check for header integrity.
There can be two types of payload:
1. Voiceand 2. Data.
Synchronous connection oriented (SCO) packets only have voice field, while
Asynchronous
connection less (ACL) packets only have data field.
Packet consist of 72 bit length for Access Code, Packet Header of 54 bits and Payload of 2745 bits.
The purpose of the FEC (forward error correction ) scheme on the data payload is to reduce the
number of retransmissions. However, in a reasonably error-free environment, FEC creates
unnecessary overhead that reduces the throughput.
Therefore, the packet definitions have been kept flexible as to whether or not to use FEC in the
payload. The packet header is always protected by a 1/3 rate FEC. It contains link information and
should survive bit errors. An unnumbered ARQ scheme is applied in which data transmitted in one
slot is directly acknowledged by the recipient in the next slot.
For a data transmission to be acknowledged, both the header error check and the cyclic redundancy
check must be satisfied, otherwise a negative acknowledgment is returned. (See Fig. 2.9)
Three error correction schemes are defined for the Bluetooth baseband controller:
1. 1/3 rate forward error correction (FEC) code.
2. 2/3 rate forward error correction code.
3. Automatic repeat request (ARQ) scheme for data.

Bluetooth Architecture
* Bluetooth is both a hardware-based radio system and a software stack that specifies the linkages
between the architecture layers of the two, The heart of this specification is the protocol stack, which
is used to define how Bluetooth works,
The Bluetooth architecture, showing all the major layers in the Bluetooth system, are depicted in the
Fig. 2.13.
The layers below can be considered to be different hurdles in an obstacle course. This is because all
the layers function one after the other. One layer comes into play only after the data has
been
through the previous layer.

ss
_. ee ae ee ae a, doe

2.25
GPAS and Mobile Data Communication

Fig. 2.13: Bluetooth Archit

ecture
Bluetooth Main Groups:
1. Radio: The Radio layer
defines the re
quirements for a Bluetooth transceiver operating in the 2.4
GHz ISM band.

2. Baseband: The Baseband layer describes the specification of the Bluetooth Link Controller (LC),
which carries out the baseband Protocols and other low-level link routines. It specifies
Piconet/Channel definition, “Low-level” packet
definition, Channel sharing
3. LMP: The Link Manager Protocol (LMP) is used by the Link Managers (on either side) for link set-
up and control.
4. HCI: The Host Controller Interface (HCI) provides a command
interface to the Baseband Link
Controller and Link Manager, and access to hardware status and
control registers,
5. L2CAP: Logical Link Control and Adaptation Protocol (L2CAP) supports higher level protocol
multiplexing, packet segmentation and reassembly, and the conveying of quality of service
information.
6. RFCOMM: The RFCOMM protocol provides emulation of serial ports over the L2CAP
protocol. The
protocol is based on the ETSI standard TS 07.10.
7. SDP: The Service Discovery Protocol (SDP) provides a means for applications to discove
r, which
services are provided by or available through a Bluetooth device. It also allows
applications to
determine the characteristics of those available services.

Ewa Wi-Max
* The ‘World Interoperability for MicroAcess, Inc. (WiMAX)’ ee an industry group, focuses on
creating advanced technology solution for high speed wide area acre access. .
The WiMAX product certification program ensures interoperability between WiMAX equipment
from vendors worldwide. ‘ 4
WiMAX can se serve as a backbone for 802.11 hotspots for connecting to the internet. Alternatively,
Users can connect mobile devices such as laptops and handsets directly to WiMAX base stations.
i i i
directly can achieve a range 0 f 4 to 6 miles.
€reoe areoe oes
2 types o ae a WiMAX (IEEE 802.16d-2004) and mobile WiMAX (IEEE802.16e-
is a multipoint-to-
Fixe WiMAX is a point-to-multipoint technology, whereas mobile WiMAX
2005). - Fixed
infrastructure.
multipoint technology, similar to that ofa cellular
 Wireless and Mobile Network 2.26 GPRS and Mobile Data Communication
munication

Salient Features Supported by WiMAX:

inclusion
1. High Data Rates: WiMAX can typically support data rates from 500 Kbps to 2 Mbps. The
elization
of multi-input multi-output(MIMO) antenna techniques along with flexible sub-chann
schemes, advanced coding and modulation all enable mobile to support peak downlink datg
rates of 63 Mbps per sector and peak uplink data rates of up to 28 Mbps per sector in a 10 MHz
channel.
2. Quality of Service (QoS): WiMAX has clearly defined QoS classes for applications with different
requirements such as VoIP, real time videostreaming, file transfer and web traffic.
29
3. Scalability: Mobile WiMAX is designed to able to work in different channelization from 1.25 to
MHz to comply with varied world-wide requirements.
cards,
4. Security: There is support for diverse set of user credentials like SIM/USIM cards, smart
‘extensibl e
digital certificates, username/password schemes. All this is based on relevant
authentication protocol (EAP)’ methods for credential type.
less than 50ms to
5. Mobility: Mobile WiMAX supports optimized handoff schemes with latencies
service degradation.
ensure that real time applications such as VoIP can be performed without
during handoff.
Flexible key management schemes assume that security is maintained
WiMAX Physical Layer (PHY):
e Forbands in 10-66GHz range, 802.16 defines one interface called Wireless MAN-SC.
e For 2-11GHz (both licensed and unlicensed):
> Wireless MAN-SC (single carrier modulation)
> Wireless MAN-OFDM (256 carrier OFDM with access to different stations using TDMA)
l station)
+s Wireless MAN-OFDM (2048 carrier OFDM by assigning subset of carriers to individua
Automatic Repeat
WiMAX PHY features include ‘Adaptive Modulation and Coding (AMC)’, ‘Hybrid
Request (HARQ)’, ‘Channel Quality Indicator Channel (CQICH)' which is a feedback channel.
speeds in excess
° All these features provide robust link adoption in mobile environment at vehicular
of 120Km/h.
WiMAX Medium Access Control (MAC):
AX base station
Each subscriber station need to compete for media only one (for entry). Then, WiM
provides time slot to each subscriber station which may increase or decrease depending on need.
and not affected
There is a scheduling algorithm for service to each station. This algorithm is robust
by over loading and over subscription.
IPv6 and Ethernet.
WiMAX supports different transport technologies such as IPv4,
each other ie
WiMAX mesh networking allows subscriber stations to communicate with
“Subscriber” mode and with base station i.e, “base station” mode simultaneously.
Spectrum Allocation for WiMAX:
« The biggest spectrum segment for WiMAX is around 2.5GHz.
e Theother bands are around 3.5HZ, 2.3/2.5GHz, or 5GHz, with 2.3/2.5GHz.
Other Features:
e The mesh mode of WiMAX enables subscriber stations to relay traffic to one another, Thus, a statio®
that does not have line-of-sight with the base station can get its traffic from another station.
e WiMAX technology can provide fast and cheap broadband access to markets that lack infrastructu®
(fiber optics, copper wire), such as rural areas and unwired countries, WiMAX can also be used
backup during disasters, which may lead the wired networks to get broken down. in
lity
* As mobile WiMAX is scalable in both radio access and network architecture, it provides flexib
network deployment options and service offerings, ,
Ss So OE oa : e
S
wireless. and Mobile Network

2.27 GPRS and Mobile Data Communication

e Mobile W: iMAX based on 802.16e uses OFDMA in which carr
iers are divided among users to for
m sub
channels. The coding and modulation are adapted separately for each
DMA that scale the nu sub channel.
mb er of subcarriers in a channel
possible values of with
128, 512, 1024, and
e 802.16e inc
ludes power-saving 2048,
and slee
+ 802.16e also supports hard and soft P modes to extend battery life if mobile devices.
handoff to provide users with seamless connections
move across Coverage areas of adjace as they
nt cells,
Difference between Wi-Fi and wima x:

Table 2.4
| Sr. No | Wi-Fi.
1. | Wi-Fi technology is based on
IEEE 802.11 | wimax technology is base
standards. d on IEEE 802.16
2 standards.
802.11a-OFDM, maxim um
802.16-OFDM, maximum rate = 50OMbps.,
rate=54Mbps.,802.11b-
DSSS,maxi mum 802.16e-OFDM, maximum rate~3OMbps.
rate=11Mbps.,802.11g-OFDM,m
aximum
rate=54Mbps.
3. The stations gain access to media
based on There is time slot for each station and there is
CSMA/CA and back off algorithm schemes.
scheduling algorithm used by base station.
4. Range is less than 100 meters,
A kilometer non-line-of-sight, more with
line-of-sight.
Indoor Environment.
Outdoor Environment.
No Quality of Service.
Five Quality of service enforced by base
station.

Se

Radio Tower

Fig, 2.14: Mesh mode in IEEE 802.16(WiMAX)

gt" neem »
GPRS and Mobile Data Commun;
2.28

[i 2
2

Ss Xx Our
J iy
Home with po! portable CPE

QTY
x ‘)Rei
o
XY
*
*)
A‘
Fixed backhaul

IEEE 802.11

Fig. 2.15 ; Applications of IEEE 802.16 (WiMAX)

Different Standards of WiMax

WiMAX is one of the hottest broadband wireless technologies around today. WiMAX systems are
expected to deliver broadband access services to residential and enterprise customers in an
economical way.
Loosely, WiMax is a standardized wireless version of Ethernet intended primarily as an alternative to
wire technologies (such as Cable Modems, DSL and T1/E1 links) to provide broadband access to
customer premises.
More strictly, WiMAX is an industry trade organization formed by leading communications,
component, and equipment companies to promote and certify compatibility and interoperability of
broadband wireless access equipment that conforms to the IEEE 802.16 and ETSI HIPERMAN
standards.
WiMAX would operate similar to Wi-Fi, but at higher speeds over greater distances and fora greater
number of users.
WiMAX has the ability to provide service even in areas that are difficult for wired infrastructure t?
reach and the ability to overcome the physical limitations of traditional wired infrastructure.
WiMAX was formed in April 2001, in anticipation of the publication of the original 10-66 GHz IEEE
802.16 specifications. WiMAX is to 802.16 as the Wi-Fi Alliance is to 802.11.
WiMAX is acronym for Worldwide Interoperability for Microwave Access.
Based on Wireless MAN technology it is a wireless technology optimized for the delivery of IP centric
services over a wide area,
It is a scalable wireless platform for constructing alternative and complementary broadband
networks.
The IEEE 802.16, the Air Interface for Fixed Broadband Wireless Access Systems, also
known as the
IEEE Wireless MAN air interface, is an emerging suite of standards for fixed, portable and mobile
BWA in MAN.
 wireless and Mobile Network

2.23 GPRS and Metile Cara Commuricaticr

EE eee Table25
Spectrum 10-66 GHz
Configuration ES ae
Line of s]j oo <6 GHz
a 3 Slight |__Non-line of slight aS
Bt a0 oes @8MHz | <700r100 Mbps (oMuz | Nomn-lne of slight
channel | Uptois Mops
;
Modulation QPSK, 16-QAM, 64-QaM | 256 sub-caChann el)
rrier OFDM using | Sameas 80216a
Mobility | QPSK, 16-QAM,256-0AM
Fixed |
Fixed $75 MPH
Channel Bandwidth’ 20.2510 pire
Lee ical cell radius | 1-3 miles
Selectable 1.25 to20MHz | 5MHz (Planned)
3-5 miles 13 mi
Completed Dec, 0
e20 2001 1-3 miles
IEEE 802.16a: Jan 2003 | 2 half off 2005
¢ WiMAX is such an easy
term that

IEEE 802.16:
Digital audio/ —_Digital
video multicast telephony Back Virtual Frame
—atyy IP Bridged LAN haui point-to-point relay

OS! data link layer

OSI physical layer

Fig. 2.16 : Protocol layers

There are Four Protocol Layers:
1, Physical Laye
r :!t is responsible for performing func
tions like encoding/decoding of signals,
8ehe rating preamble, transmitting/receiving a data
bit. It comprises of the frequency band and
"edium of transmission.
Transmission Layer: It deals with enco ’
ding/decoding signals, generating prea
mble, transmitting /
"eceiving data bits,
Medium Access Control Layer (MAC) Layer: It is resp
onsible for transmitting the data frames and
“ntrolling wireless access. This layer is simple.
It indicates when a subscriber or base Station can
begin tran
Smisession.
: onvergence Layer: It provides functions that are required for providin‘ g a part
icular service,
 et ee fF -*.' == med

- a “4
&,

GPRS and Mobile Data Comm

Wireless and Mobile Network 2.30 Un Catia,

Speed and Range: ; :

* WIiMAXis epee to offer initially up to about 40 Mbps capacity per Cee ee ae fixey
and portable applications, depending on the particular ee ds of residences a
support hundreds of businesses with T-1 speed connectivity and eeat rats ee e
ee - competi
speed connectivity. WiMAX can support voice and video as well cE ae existing
either 1
* WiMax developed to provide wireless broadband access to buildings,
wired networks or alone in currently unserved rural or thinly populated areas. © Used to
connect WLAN hotspots to the Internet. ;
* WiMAX is also aenael to provide broadband connectivity to mobile device’: i ae Be as fast
as in these fixed applications, but expectations are for about 15 Mbps capacity in a 3 km cell coverag,
area.
* With WiMAX, users could really cut free from today's Internet access arrangements and be able to py
online at broadband speeds, almost wherever they like from within a Metro Zone.
WiMAX could potentially be deployed in a variety of spectrum bands: 2.3GHz, 2.5GHz, 3.5GHz, and
5.8GHz.

Rees Advantages of WiMAX

WiMAX can satisfy a variety of access needs. Potential applications include extending broadband
capabilities to bring them closer to subscribers, filling gaps in cable, DSL and T1 services, Wi-Fi, and
cellular backhaul, providing last-100 meter access from fiber to the curb and giving service
providers another cost-effective option for supporting broadband services.
WiMAX can support very high bandwidth solutions where large spectrum deployments (i.e. >10 MHz)
are desired using existing infrastructure keeping costs down while delivering the bandwidth needed
to support a full range of high-value multimedia services.
WiMAX can help service providers meet many of the challenges they face due to increasing customer
demands without discarding their existing infrastructure investments because it has the ability to
seamlessly interoperate across various network types.
WiMAX can provide wide area coverage and quality of service capabilities for applications ranging
from real-time delay-sensitive Voice-over-IP (VoIP) to real-time streaming video and non-real-time
downloads, ensuring that subscribers obtain the performance they expect for all types of
communications.
WiMAX, which is an IP-based wireless broadband technology, can be integrated into both wide-arét
third-generation (3G) mobile and wireless and wireline networks allowing it to become part of #
seamless anytime, anywhere broadband access solution,
Ultimately, WiMAX is intended to serve as the next step in the evolution of 3G mobile phones, via #
potential combination of WiMAX and CDMA standards called 4G,

ya wmee] Wi-MAX Technology

* WiMax stands for World Interoperability for Micro-wave Access. WiMAX is optimized for p-based
high-speed wireless broadband which will provide for a better mobile wireless broadband intern®
experience. ’
Features of WI-MAX Technology :
1, WiMAX can typically support data rates from 500 kbps to 2 Mbps.
a _ 2. WiMAX also has clearly defined QoS classes for applications with different requirements such 8
4
a VoIP, real-time video streaming, file transfer, and web traffic.
5
— Ne eee eee
wireless 200 Motile Network
ree
2 GPRS and Mchiie Dats Communication
architecture similar tp that of 5
Aota Sn 3
controlling downlink/uplink * Officmobile Phon
phor e systems can be used
sed wit
with a central base
family of technologies based
=
Wt

tyPes Of WIMAX. fixed Wik

int-to-mulkinoint te {AX (Point-to- multipoint Technology) and mobi
ht
chnolo le WIMAX
6. gy).
WIMAX uses orthosSo
o;na l frequency diivi visision multiple access (OFDMA) te
rite. rent advantages in 4. Spectral efficiency chnology wh= ich has
ee mance
5th perfor ¥ nced anter nna perfo rman ce, an d impPproved
ncy, adva
devices conn dire ct}ly can
&
Scted dir ect
achievea : range of 4 to 6 miles.
Frequency band
-2 to 17 GHz (unl
¢. icensed).
cha + Panlcwicth: 125 Mu
ze 20 MHz
advantages

2 Speed of 10 Mbps at10 Kil

ometers with line-of-sight.
Disadvantages:
L Line of sight is needed for
longer connection.
2 oie conditions like rain can interrupt
the signal
3.Other wireless equipment’s can int
errupt the signal
4. Multiplied frequencies are used
Applications:
L Tilevelservice for enterprise.
DSL level service for SOHO.
me wp

Wireless backhaul for hotspots.

NAW

Coverage is 50 km.
Modulation.
Uplink S OFDMA
Downlink S OFDMA.
Channel bandwidth 40MHz.
PM

. Speed-—120 Km/hr.
10. Compliance ~ non compliant with 2G and
36.

2.4.3 BY so31
* WiFi stands for Wireless Fidelity. WiFiis lt
based on the IEEE 802.11 family of standards and is
ep 2 Local Area Networking (LAN) techno logy designed to provide in-building bro
adband
coverage.
. t WiFi systems t a peak physical-layer data rate of $4
Mbps and typically provide
indoor coverage over a distance of 100 feet.
* WiFi has become the de facto standar Ce
public f oe eee ee
can typically providc
e a cove
erage c eYann bones, offices, and
range of only about 1,000 feet
«aifom
e the
caeaccess point. , peak data rates than do 3G systems, prim
imari
arilly y sinsi ce it operat
es over a
larger 20 MHz bandwidth, but WiFi systems are not designed to support high-speed mobili
ty.
 °.

Wireless and Mobile Network 2.32 GPRS and Mobile Data Commun
———catlon

Fig. 2.17: Wi-Fi Technology

* One significant advantage of WiFi over WiMAX and 3G is its wide availability of termina
l devices. 4
vast majority of laptops shipped today have a built-in WiFi interface. WiFi interfaces are now
also
being built into a variety of devices, including Personal Data Assistants
(PDAs), cordless phones,
cellular phones, cameras, and media players.
WiFi is Half Duplex:
¢ All WiFi networks are contention-based TDD systems, where the access point and
the mobile stations
all vie for use of the same channel. Because of the shared media operation, all WiFi
networks are half
duplex.
e There are equipment vendors who market WiFi mesh configurations,
but those implementations
incorporate technologies that are not defined in the standards.
Channel Bandwidth:
e The WiFi standards define a fixed channel bandwidth of 25 MHz
for 802.11b and 20 MHz for either
802.11a or g networks.

yee ee Wi-Fi - Working Concepts

Radio Signals:
Radio Signals are the keys, which make WiFi networking possible, These
radio signals transmitted from WiFi antennas are picked up by WiFi
receivers, such as computers and cell phones that are equipped with
WiFi cards.
Whenever, a computer receives any of the signals within the range of
a
WiFi network, which is usually 300 — 500 feet for antennas, the WiFi
card reads the signals and thus creates an internet connecti
on between
the user and the network without the use of a cord,
e Access points, consisting of antennas and routers, are the
main source
that transmit and receive radio waves. Antennas
work stronger and
have a longer radio transmission with a radius of Fig. 2.18 : Wi-Fi concept
300-500 feet, which
are used in public areas while the weaker yet effective
router is more
suitable for homes with a radio transmission of 100-150
feet.
WiFi Cards:
WiFi cards are invisible cords that connect your computer
to the antenna for a direct connection to
the internet.
_~ * MEA Ng Ne lis GF ae
jess and Moblle Notwork
wi ral
: wiFi cards can 2.33 GPRS and Mobile Data Communication
be external or
purchase @ USB interna L Ifa Wi
antenna attach j card isi not in i stalled i n your computer, then you may
antenna-equipped ment and have
expansion carq inst jt ex te rn ally conne ct to your USB port, or have
, For laptops, this ca al led dir an
rd will bea PCMC (as shown in the Fig. 2.19).
IA ca

ents. 802.11b is the most common spec

hotspots worldwide, ification for
:
+ The 802.11g standard is backwards comp
atible with -11b but .11a uses a differen
and requires separate hardware such t frequency range
as an a, 8/g, or a/b/g adapter,
* The largest public WiFi networks are
provided by private internet service Prov
charge a fee to the users who want to access the iders (ISPs); they
internet.

Fig, 2.20 : Wi-Fi Hotspot - =

:
Hotspots are increasingly developing around the wor ld. In fact, T-Mobile
ne USA controls more than
om
4,100 hotspots located in publiclocations such as Starbucks, Borders, oe ,bees
and the ate
airlin ons of
Delta, meUnited
is : e a d US aiAirways.in Even select McDonald's restaurants no ecess.
tegrated wireless, a wireless adapter attached to a ees by
Seon Compaen CIA card can accessa wireless network.
the Manufacturer, or a wireless adapter such as
a roe
)
 Te a;
ae a Say, .

aaa GPRS and Mobile Data Communication

Wireless and Mobile Network

Furthermore, all Pocket PCs or Palm units with Compact Flash, SD 1/0 support, or built-in WiFi, Can
access hotspots.
* Some Hotspots require WEP key to connect, which is considered as private and secure. As t0n Open
connections, anyone with a WiFi card can have access to that hotspot. So in order to have internet
access under WEP, the user must input the WEP key code.

| 2.4.3.3 | WiFi IEEE Standards

* The 802.11 standard is defined through several specifications of WLANs. It defines an over-the-air
interface between a wireless client and a base station or between two wireless clients.
° There are several specifications in the 802.11 family —
1, 802.11: This pertains to wireless LANs and provides 1 - or 2-Mbps transmission in the 2.4-GHz
band using either Frequency-Hopping Spread Spectrum (FHSS) or Direct-Sequence Spread
Spectrum (DSSS).
2. 802.11a : This is an extension to 802.11 that pertains to wireless LANs and goes as fast as 54 Mbps
in the 5-GHz band. 802.11a employs the Orthogonal Frequency Division Multiplexing (OFDM)
encoding scheme as opposed to either FHSS or DSSS.
3. 802.11b : The 802.11 high rate WiFi is an extension to 802.11 that pertains to wireless LANs and
yields a connection as fast as 11 Mbps transmission (with a fallback to 5.5, 2, and 1 Mbps
depending on strength of signal) in the 2.4-GHz band. The 802.11b specification uses only DSSS.
Note that 802.11b was actually an amendment to the original 802.11 standard added in 1999 to
permit wireless functionality to be analogous to hard-wired Ethernet connections.
4. 802.11 : This pertains to wireless LANs and provides 20+ Mbps in the 2.4-GHz band.
e Here is the technical comparison between the three major WiFi standards.
__Table 2.6
ES > ‘Feature WIFI (802.11b) 2 | WiFi (802.11a/g
Primary Application Wireless LAN Wireless LAN
Frequency Band 2.4 GHz ISM 2.4 GHz ISM (g)
5 GHz U-NII (a)
Channel Bandwidth 25 MHz _ 20 MHz
Half/Full Duplex Half Half
Radio Technology Direct Sequence OFDM
Spread Spectrum (64-channels)
Bandwidth <=0.44 bps/Hz S=2.7 bps/Hz
j Efficiency ¢ ?
= Modulation QPSK
er BPSK, QPSK, 16-, 64-QAM
FEC None Convolutional Code
Encryption Optional- RC4m (AES in 802.111) Optional- RC4(AES in 802.111)
Mobility In development In development
Mesh _ Vendor Proprietary Vendor Proprietary
Access Protocol CSMA/CA CSMA/CA =

| items Wi-Fi- Access Protocols

TEEE 802.11 wireless LANs use a medi
@ access control protocol called Carrier Sense
with Collision Avoidance (CSMA/CA Multiple Access
). While the name is similar to Ethernet's Carri
___ Access with Collision Detection (cs er Sense Multiplé
MA/CD), the operating concept is totally diff
erent,
- EEE Ie SP Sea!ae
and Mobile Network
reless.
s <5 GPRS and Mobile Data Communication
wiFi systems are the half duplex shared medi :
edia configurations, where all stations transmit and
.

receive on the same radio channel.

pistributed Control Function (DCF)

rding to DCF, a WiFi i : :
Sais ed, soifast Saeee will transmit only when the channel is clear. All transmissions are
Coe N cans ation does not receive an acknowledgement, it assumes a collision occurred
and retries after a random waitin g interval.
incidence of collisi il i : ;
; te. ons will increase as the traffic increases or in situations where mobile
stations cannot hear each other.

ea Wi-Fi - Quality of Service (QoS)

» There are plans to incorporate quality of service (QoS) capabilities in WiFi technology with the
adoption of the IEEE 802.11e standard,
¢ The 802.11e standard will include two operating modes, either of which can be used to improve
service for voice:
1, WiFi Multimedia Extensions (WME) - Mandatory
2. WiFi Scheduled Multimedia (WSM) - Optional
3. WiFi Multimedia Extensions (WME)
* WiFi Multimedia Extensions use a protocol called Enhanced Multimedia Distributed Control Access
(EDCA), which is an extension of an enhanced version of the Distributed Control Function (DCF)
defined in the original 802.11 MAC
* Theenhanced part is that EDCA will define eight levels of access priority to the shared wireless
channel,
* Like the original DCF, the EDCA access is a contention-based protocol that employs a set of waiting
intervals and back-off timers designed to avoid collisions.
* However, with DCF all stations use the same values and hence have the same priority for
transmitting on the channel.
* With EDCA, each of the different access priorities is assigned a different range of waiting intervals

and back-off counters.

r intervals. The standard also includes
* Transmissions with higher access priority are assigned eS
a packet-bursting mode that allows an access point or a mobile station to reserve the channel and
Send 3- to 5-packets in a sequence.
WiFi s cheduled Multimi edia (WSM)M): h the optional WiFi Scheduled Multimedia (WsM).
F ided wit
True consistent delay services can be provide : ee
(PCF) defined with the original , 802.11
MAC,
WSM operates like - little used Point Control Function that forc es all stat ions to treat
onal ally broadcas ts a control message
oint periodic tran smit . Duri ng that period, the access point polls each
1 WSM, tthe ri P d aa= a atte mpt to
nel as busy an
itive to serv
s need
ime sens ice. a traffic profile describing bandwidth, latency, and
send
m on that isi Ce for ie
ae
he the WSM option, ein point does not have sufficient resources to meet the traffic profile,
requirements. If the acce
{twill return a busy signal.
 Bah Fh * — *
a

Wireless and Mobile Network 2.36 GPRS and Mo bile Data Communicat on

EXER Wi-Fi Security

Security has been one of the major deficiencies in
WiFi, though better Cn Tae now
becoming available. Encryption is optional in WiFi, and two different techniques have been defined,
* These techniques are given
here -
1. Wired Equivalent Privac
* AnRC4-based 40-or Teahee P ortke with a static key. WiFi Protected Access (WPA).
s/thisisa hem sian dard from the Wifi Alliance
that uses the 40 or 104-bit WEP key, but it change
s the
key on each packet. That changing key functionality is called the
Temporal Key Integrity Protoco]
(TKIP).
2. IEEE 802.11i/wPa2
° The IEEE is finalized the 802.11i standard, which is based on a far more robust encryptioi n technique
i
called the Advanced Encryption Standard.
* The WiFi Alliance designate products that comply with the 802.11i standard as WPA2. However,
implementing 802.11i requires a hardware upgrade.

-aeeeita Wi-Fi Network Services

* The picture has become somewhat confused as service providers started using WiFi to deliver
services for which it was not originally designed.
* The two major examples of this are Wireless ISPs and City-wide WiFi mesh networks.
1. Wireless ISPs (WISPs)
One business that grew out of WiFi was the Wireless ISP (WISP). This is an idea of selling an Internet
access service using wireless LAN technology and a shared Internet connection
in a public location
designated as a hot spot.
From a technical standpoint, access to the service is limited based on the transmission
range of the
WLAN technology. You have to be in the hotspot (i.e. within 100m of the access
point) to use it.
From a business standpoint, users either subscribe to a particular
carrier's service for a monthly fee
or access the service on a demand basis at a fee per hour.
While the monthly fee basis is most cost effective,
there are few inter carrier access arrangements,
so you have to be in a hotspot operated by your carrier in order
to access your service.
2. City-Wide Mesh Networks
To address the limited range, vendors like Mesh Network
s and Tropos Networks have developed mesh
network capabilities using WiFi's radio technology.
¢ The idea of a radio mesh network is that messages can
be relayed through a number of access
points
to a central network control station. These network
s can typically support mobility as connections
are handed off from access point to access point
as the mobile station moves.
* Some municipalities are using WiFi mesh
networks to support public safety applications
(i.e.
terminals in police cruisers) and to provide Internet access to the community
spot).
(i.e. the city-wide hot
Wi-Fi - Radio Modulation
* WiFi systems use two primary radio transmission techniques.
1. ae eae ae radio link uses a direct sequence spread spectrum
technique
: Quadrature ying (CCK). The bit stream
modulated using is processed with a special coding and then
Phase Shift Keying (QPSK).
 SS et Se NS ae ee eh.
d i
Orr Tl eS

Wireless and Mobile Network

2.47 GPRS and Mobile Data Communication

2, 802.11a and g (<=54 Mbps): The 802.11a

and g systems use 64-channel Orthogon
Division Multiplexing (OFDM), In an OFDM modulation al Frequency
system, the available radio band is divided
into a numb er of sub-channels and some of the bits are sent on each, The
transmitter encodes the
bit
streams on the 64 subcarriers using Binary
Phase Shift Keying (BPSK), Quadrature Phase
Keying (QPSK), or one of two levels of Quadrature Shift
Amplitude Modulation (16, or 64-QAM). Some of
the transmitted information is redundant, so the rece
iver does not have to receive all of
carriers to reconstruct the sub-
the information,
« The original 802.11
Specifications also included
spectrum (FHSS), but that an option for frequencyhopping spread
has largely been a bandoned,
Adaptive Modulation:
1. WiFi uses adaptive modu
lation and va tying levels of forward
transmission rate and error error correction to optimize
performance
2. As a radio signal loses pow
er or encou nters interference, the error rate will increase. Adapti
modulation means that the trans ve |
mitter will automatically shift to a more
efficient, modu robust, though less
lation technique in those adverse condi
tions,

(eee Wi-Fi Major Issues

* There are a few issues that are assumed to be the |
cause behind the sluggish adoption of WiFi
technology :
1. Security Problems: Security concerns have held
back WiFi adoption in the corporate world.
Hackers and security consultants have demo
nstrated how easy it can be to crack curr
security technology known as wired equivalent ent
privacy (WEP) used in most WiFi connections,
hacker can break intoa WiFinetwork using readi A
ly available materials and software.
2. Compatibility and Interoperability: One of
the major problems with WiFi is its compa
and interoperability. For example, 802.11a tibility
products are not compatible with 802.11b
Due to different operating frequencies, products.
802.11a hotspots would not help an 802.11b client. Due to
lack of standardization, harmonization,
and certification, different vendors come
products that do not work with each other. out with
3. Billing Issues: WiFi vendors are also looking for ways to
solve the problem of back
integration and billing, which have dogged the roll-out of comm -end
ercial WiF i hotspots. Some of
ideas under consideration for WiFi billing such as per day, per hour, the
and unlimited monthly
conne ction fees.
:
4. Wi-Fi Summary: WiFi is a universal wireless networking technolo sy that utilizes
radio
frequencies to transfer data. WiFi allows high-speed Internet conne
cti ons without the use
cables, The term WiFi is a contraction of "wireless fidelity" and com mo of
nly used to refer
wireless networking technology. The WiFi Alliance claims rights to
in it S uses as a certific
mark for equipment certified to 802.11x standards. ation
5. WiFi is a Freedom: Freedom from wires. It allows you to
connect to the Internet fro m just
anywhere - a coffee shop, a hotel room, or a conference room at work, It is almost 10 tim about
than a regular dial-up connection. WiFi networks opera es faster
te in the unlicensed 2.4 radio bands,
an 11 Mbps (802.11b) or 54 Mbps (802.11a) data rate, respectively. with

6. To access WiFi, we need WiFi enabled devices (laptops or PDAs). These devices can send and
receive data wirelessly in any location equipped with WiFi
access.
Wireless and Mobile Network 2,38 GPRS and Mobile Data Communication

25 MOBILE IP
Mobile IP is a proposed standard protocol that builds on the Internet Protocol oy maine mobility
transparent to applications and higher level protocols like TCP.
Mobile IP is an open standard, defined by the Internet Engineering Task Force (IETF) RFC 2002 that
allows users to keep the same IP address, stay connected, and maintain ongoing applications while
roaming between IP networks.
Mobile IP is scalable for the Internet because it is based on IP—any media that can support IP can
support Mobile IP.

Server X
Fig. 2.21: Mobile IP Scenario
Mobile IP is designed to support host mobility on the internet. User is connected to one or more
applications across the internet, the user's point of attachment changes dynamically and that all
connections are automatically maintained despite the change.
Server X transmits an IP datagram for mobile nodes A with A's address in IP header. IP datagram is
routed to A’s home network.
At home N/w the incoming IP datagram is intercepted by home agent. The home agent encapsulates
the entire datagram inside a new IP datagram. The use of an outer IP datagram with a different
destination IP address is known as “tunneling”. This IP datagram is routed to foreign agent.
Foreign agent strips off the outer IP header, encapsulates the original IP datagram in a N/w level
Packet Data Unit (PDU) and delivers the original datagram to A across the foreign network.
When A sends the IP datagram to X, it uses X's IP address. This is a fixed address that is X is not
mobile node. Each IP datagram is sent by A to a router on the foreign network to X. This router is al5°
a foreign agent.
The IP datagram from A to X travels directly across the Internet to X, using X’s IP address.
41. Mobile IP Capabilities
2. Registration
3. Discovery
4. Tunneling
 : i ee Oe abl. ae eee
eless and Mobile Network
wires
2.39 GPRS and Mobile Data Communication
Agent Advertis
ement Packet in cluding Mo
bility Extension
Mobile nodes use agent advertisements to determine
internet or to an organization's network their current point of attachment to the
An agent advertisement is an Inte
has been extended to also carry a ae Control Message Protocol (ICMP) router advertisement that

» Agent Discovery is the method b mobility agent advertisement extension.

; home
to its network or to a foreign network
¥ which a mobile node determines
it i ently connected
moved from one network to anche , and b y which
i Sabet ee arta
i node can detect when iit has
a mobile

» When connected toa foreign network, the metho

ds specified in this section also allow the mobile
node to determine the foreign agent care-of add
ress being offered by each foreign agent on that
network.
« Mobile IP extends ICMP Router Discovery as its
primary mechanism for Agent Discovery. An Agent
Advertisement is formed by including
a Mobili ty Agent Advertisement Extension in an ICMP Router
Advertisement message,
Agent Discovery:
A mobile node has to find a foreign agent when it moves
away from its home network. To solve this
probl em, mobil:e IP describes two methods namel
y, agent advertisement and agent solicitation.
1, Agent Advertisement:
For this method, foreign agents and home agents advert
ise their presence periodically using special
agent advertisement messages, which are broadcast into the subnet
.
Mobile IP does not use a new packet type for agent adver
tisement; it uses the router advertisement
packet of ICMP, and appends an agent advertisement message.
* The agent advertisement packet according to RFC 1256 with the extension
for mobility is shown
below.

0 7|8 15] 16 23| 24 31

tupe code checksum
#addresses| addr.size lifetime Upper part (ICMP packet)
router address 1
preference level 1
router address 2
preference level 2

type = 16 length sequence number

registration lifetime WE) H] FIM|G| r|T| reserved Lower part (mobility ext)
COA 1
COA2

t packet
Fig. 2.22: Agent advertisemen
The Tr, field of the IP packet is set to 1 for all advertisements to avoid forwarding them. The Type is
Setto9 the codecan = 0, if the agent also routes traffic from non-mobile nodes, or 16, if it does not
ute anything other than mobile traffic.
“number of addresses advertised with this packet is in #addresses while the addresses themselves
low as shown,
 Wireless and Mobile Network 2.40 GPRS and Mobile
Mobile Data Com MUNI Cation

Lifetime denotes the length of time this advertisement is valid. Preference levels for each addrag,
help a node to choose the router that is the most eager one to geta new node,
The extension for mobility has the following fields defined: type is set to 16, length depends on the
number of COAs provided with the message and equals 6 + 4*(number of addresses).
The sequence number shows the total number of advertisements sent since initialization by the
agent. By the registration lifetime the agent can specify the maximum lifetime in seconds a node
can request during registration.
* The following bits specify the characteristics of an agent in detail:
5 The R bit (registration) shows, if a registration with this agent is required even when using a co.
located COA at the MN.
© Ifthe agent is currently too busy to accept new registrations it can set the B bit.
The following two bits denote if the agent offers services as a home agent (H) or foreign agent
(F) on the link where the advertisement has been sent.
Bits M and Gspecify the method of encapsulation used for the tunnel. While IP-in-Ip
encapsulation is the mandatory standard.
M can specify minimal encapsulation and G generic routing encapsulation,
In the first version of mobile IP (RFC 2002) theV bit specified the use of header compression
according to RFC 1144, Now the field r at the same bit position is set to zero and must
be ignored.
The new field T indicates that reverse tunneling is supported by the FA. The following
fields
contain the COAs advertised. A foreign agent setting the F bit must advertise at least
one COA.
A mobile node in a sub-net can now receive agent advertisements from either
its home agent ora
foreign agent. This is one way for the MN to discover its location,
2 Agent Solicitation:
.

Every mobile node should implement agent solicitation, The mobile node
uses the same procedures, _
defaults, and constants for agent solicitation, as specified
for ICMP router solicitation messages.
The rate at which a mobile node sends solicitations is limited by the mobile
node. The mobile node
can send three initial solicitations at a maximum rate of one per second
while searching for an
agent,
* After registering with an agent, the rate at which solicitations
are sent is reduced, to limit the
overhead on the local network.

Components of Mobile IP
* Mobile IP (or MIP) is a communications protocol that allows users
to move from one network to
another network with same IP address, |
* It ensures that communication will continue without
user's sessions or connections being dropped. .
When a user leaves the home network and enters in another network
(foreign network), the foreign
network uses the mobile IP protocol to inform the home
network of a care-of address to which all
packets for the user's device should be sent.
* Home Address is the permanent IP address
assigned to the mobile node. Mobile node
address in its home address. Care-Of Address uses this
(COA) is the temporary address used by a mobile node
while it is moving away from its home network,
* Mobile IP has the following three components
namely, Mobile Node, Home Agent and Foreign
1, Mobile Node: Any device those have roaming Agent.
facility such as a cell phone, personal digital
assistant, or laptop,
 ee Oe NCU, OOP a ee ee

wireles: sand Mobile

Ho Network
2.41 GPRS and Mobile Data Communication
Zz Home Agent: It is a rou
ter on
Mobile Node. It stores ing, the home network and working as communication point with the
: °rmation about mobil
e nodes whose permanent home address is in
home agent's network. It tunnels data from the
a called a Correspondent Node, to the roam
Mobile Node. ing
3 Foreign Agent: It available
in anothe T network and
visiting its network. The Forei stores information about mobile nodes
&N Agent is a Touter that advertises care-of addresses, which are
used by mobile IP. It also
de livers packe
roaming in another networ ts from the Home Agent to the Mobile Node while
k.

yee (ROCs ales its

L Describe the GPRS architecture and pro
tocols, How many of them alread
2 . Toaccommodate GpRs, What y exist in GSM?
modi fications are made to
3 _ Which part of GPRS interface BSS?
shou ld be modified if ATM rep laces frame relay?
4 . Compare channel requ
est procedu re in GPRS wit
h that in GSM.
5. Write short not e on: GPRS for 2.5G
GSM and Is-136,
6 Explain GPRS Services,
7 What are limitations and
applications of GpRs.
8 . Write short note on GPRS-Quality
of service.
9 Explain data packet routing and mob
ility Management in GPRS
10, Explain logical channels in GPR
s.
11. Explain why PDP context fields
stored in MS, HLR, GGS N and SGSN are different
text is not stored in and why PDP on
VLR.
12. Why does GSM utilize GPRS to
Carry out location update for circuit
switched service?
33. In terms of the number of data
links that can be established, what is
the difference between
GPRS data connection from an MS to external data
networks and dial up connection to the
networks?
data
14. In Alcatel’s GPRS solution, every GPRS netw
ork is supported by one SGSN and GGSN. In
Nortel's
solutio n, several SGSN and
GGSN are used to support one GPRS network. C
ompare these two
approaches.
15, How do you implement prepaid service in GPRS?
16 . What are different IEEE 802.11 WLAN Standards.
17, Explain primary IEEE 802.11 Specifications and their comparison w.r.t approval date, maxi
mum
data rate, modulation, RF band, Number of special streams, channel width.
1 What are the applications of WLAN.
oo

1 - Draw and explain IEEE 802.11 WLAN architecture.

wo

20 Compare various IEEE 802.11 standards w.r.t applications, modulation, channel width,
typical
range, antenna configurations. ue
2 What is RFID? Discuss some of its applications.
i

2 - Explain RFID components and their characteristics.

mn

2 - What are RFID

features.
iw

- What is RFID? Discuss different components of RFID and explain how communication takes
Place among the components.
- Explain the risks and benefits of applying RFID in the manufacturing sector. How
ector.
can it be
adopted in tracking parcels for the ecommerce s
 = @ wee es i —
—
a *

3
GPRS and Mobile Data COMMUNIcation
Wirstess: act Wobile Network mae a
Wrieee = — Sal ie cutie a RFID. :
Nm ascent ei amon
MAC address, parked unit, sniff and hold mode.
se Blutooth ; Piconet, scatternet, Master unit, slave ypiy

Expizin the frame format in Bluetooth technology.

NRRRR
Expiein in detail Bluetooth architecture.
- Write short note on WiMAX Technology
What ave salient features supported by Wimax
.
Expli WIMAX physical layer. WIMAX Medium
: access control, spectrum allocation for Wi iMAX,
Gther festures of WIMAX.
33. What is the difference between Wi-Fi and WiMAX.
A. Wrat is WiMAX, Explain with its different standards.
33. What are advantages and applications of WIMAX
26. What is WLI?
27. Explain Wi-Fi working concepts such as radio signals, Wi-Fi cards, Wi-Fi Hotspots.
2. What are various Wi-Fi IEEE Standards.
3. Comspare WEFi (202.11b) and Wi-Fi (202.11 a/g)
40, Explein access protocols and control functions in Wi-Fi
41. Explain Wi-Fi Quality of service
42. Explain Wi-Fi security
42, Exphain Wi-Fi network services.
44, Winat are different Wi-Fi maior issues
45. Witite thor note on mobile IP.
44. iow the agent can be discovering using mobile IP?
Give the overlay of agent advertisement

44, What is mobile IP? Explain various components of mobile IP.

+e
 aah
ee
ST eRe
a
SOL utcomes...
eee i eee eee ee ae

a : patibility requirements of IMT - 2000 global standards.

@ Explain features of the given next generation
standard.
| Describe the function of the given section of UMTS networ
k architecture.
a Compare features of the two given next generation mobile communication networks based on given
criteria.
State the procedure of scheduled maintenance of the given system.
@

meas

meen a Zoe ae

® To understand Basic Concepts in WAP

To learn various 3G Mobile Services
=

To understand WML and UMTS Technology

=

To study Features of 4G
&

cme
oes
Sars

* WAP (Wireless Application Protocol) WAP is a universal open standard developed by the WAP forum
to provide mobile users of wireless phones and other wireless terminals.
* WAP standard represents the first successful attempt to establish a broadly accepted environment
for delivering information, data and services to both enterprise and consumer users over wireless
networks.
* WAP is based on existing internet standard such as IP, XML, HTML and HTTP. It also includes security
features,
* WAP bridges the gap between mobile world and Internet as well as corporate intranets and offers the
ability to deliver an unlimited range of mobile value added services to subscribers-independent of
their network, bearer and terminal. ‘
Mobile subscribers can access the same wealth of information from a pocket-sized device as they can
from the desktop. ‘
WAP is a global standard and is not controlled by any single company. E rricson, Nokia, Motorola and
unwired planet founded the WAP forum in the summer of 1997 with the initial purpose of defining
an industry-wide specification for developing applications over wireless communications networks,
[3.1]
 e ee ee eS 8g
74

Wireless and Mobile Network 32 i

ction s oo
en yeaa
WAP specification define a set of protocols in application.
* The
transport layers, which enable operators, manufacturers ane a ecxiie creation. *
challenges in advanced wireless service differentiation and fast/fl bling operators, manufacturey
lications includi
* WAP also defines an application environment (WAE) aimed at enabling
wt rendeet nase :
and content developers to develop advanced differentiating services and
Bing
micro browser, scripting facilities, email, World wide Web (WWW)-to SERN
and mobile to telefax access.
¢ WMLstands for Wireless Markup Language. WMLis an application ofthat XML, which Is cee ihe
so it can be compared with
definition. WMLis based on HDML and is modified
document-type
and the low bandwidth of transmission.
HTML. WML takes care of the small screen support for
environment urgently requires
e IMT-2000 Global Standard is emerging Internet
based on high speed packet data transport.
asymmetric, interactive, multimedia traffic
Such rapidly growing service requirements given by the global users of requirements, will
the
services and the underlying networks in
dramatically change the nature of telecommunication
twenty first century.
(IMT-2000), where 2000
* This standard is known as International Mobile Telecommunications-2000
radio frequency band
indicates the target availability data (year 2000) as weil as the operational
known as Future Public Land Mobile
(2000 MHz range) for the standard until 1997,IMT-2000 was
Telecommunication Systems (FPLMTS).
CDMA stands for Code Division Multiple Access. The 3G W-CDMA is based on the network
*
global standards.
fundamentals of GSM and uses 3G technologies covered in the IMT-2000
by RACE
° UMTS stands for Universe of Mobile Telecommunications System. It is being developed
(3G) wireless
(Rand in Advanced Communication technologies in Europe) as the Third Generation
system.
* UMTS uses a totally different radio interface based around the use of direct sequence spread
spectrum as CDMA (Code division Multiple access),
- «Inthe field of mobile communication services, the 4G mobile services are the advanced version of
the 3G mobile communication services.
¢ Currently in the network technology, one of the most talked terms is Fifth Generation (5G) networks.
Although it is well informed that 5G is going to be launched by 2020, but still is a lot of buzz about its
‘upcoming features, additional benefits in comparison to 4G resource requirement to implement the
5G.

ake nb BLAND
hi Shine
+ the ele

e WAP utilizes Internet standards such as XML, user datagram protocol (UDP).and IP. Many of the
protocols are based on Internet standards such as Hypertext Transfer Protocol (HTTP) and TLS
(Transport Layer Security) but have been optimized for the unique constraints of the wireless
environment: low bandwidth, high latency and less connection stability.
Internet standards such as Hypertext Markup Language (HTML), HTTP, TLS and transmission control
protocol (TCP) are inefficient over mobile networks, , requiri ‘ d
requiring lar
g large amount of mainly text bas¢
data to be sent.
, wee ili 7 i
 WAP Gateway
qhe WAP Gateway utilizes Web pro:
t ern
:
Aproxy plays the roles of both Es cli
aide o> DRE etnies ieiats
be e client. es EET:
half of thutcees
ha nd se t (a client) rca N noen t.making requesuntsicon
ate with the origin server(a ss web
pe ca us e th e WP
A P Ga te wa y se rv es asa p t di re ct ly co mm se t, an ' d pa es
server), the WA le the requests from the
WAP ha nd
igin servers. oxy to hand
the requests to the or
y ).9translates requests from the WAP protocol stack to the
Internet si
5 on the Internet tocol side the WAP Gat
and ewa
TCP /1p
internet pro stack (HTTP in the
b .On the wire less net wor k side,the encoder/decoder
forms WML text and ation transmitt ed
waP Gateway perhet
wir ele ss nrke, ytecode conversion to reduce the inform
over the
d in URLs.It
‘ e WAP Gateway typicall
eee ee service to resolve the domain names use
a provides am if regating data from different orig
in
y used Kh@omter by agg
gervers,and by caching frequentl
ica tio ns do not s pecicity : s for chargi:ng or subscription
» Though the WAP spe cif ; fy mec han ism
ation can be collected
management, the WAP arc hit ecture suggests that appropriate chargin, inform
y ,wh ere the WAP secu to mer
ri ty protocolaecan be usedpea nme
authen ticate the subscribi er.
inth e WAP Gat ewa illation
Alt hou gh
ae
it is not def ine d in the WAP specifications, WAP Gateway may Use the dist
‘
ation,which effectively reduces the wireless traffic.
techmigue be perform on-demand transform preserves most of the
type specific compression that
+ Distillation is highly lossy, real time, data colors and
ten t of a doc ume nt. It scal es dow n a color image by reducing the number of
semantic con tion of video to
of the rep res ent ati on or red uce s the frame size,frame rate and resolu
thus the size
on.
create a reduced quality representati retr ieve a simplified version of an object.I
f
ows the user to quic kly
* The distilled representation all t is used to fetch extra information to enh
ance
is req uir ed, ref ine men
more information of the object
cate that this
the distilled object.
ormation increases the latency at the proxy,studies indi
« Although on-demand transf to end late ncy with better output for the
clients.
less handheld devices can
red uce s end
technique significantly s in the WAP Gat ewa y,w ire
* By installing dynamic adaptation mechanism their own.
not achieve on
erf ul inf ras tru ctu re to achieve capabilities they could Gateway and
leverage a pow
pro duc t avai labl e on the market.The Motorola WAP
ware -
* The WAP Gateway is a middle win dow s NT pla tform.
y are based on the are
the Erricson WAP Gatewaped ys on the Uni x pla tfo rm.Nokia 3s WAP Gateways
their WAP Gatewa its WAP Gateway beta
* APION and CMG develo offers a free download of
and Windows NT.Nokia
developed in both Unix
Web site, forum.nokia.com.
product from its

c h i t e c t u r e and Protocols
WAP Ar
EE WAP Gateway tu re is given below:
A P Ar ch it ec
* The description of W ve lo pm en t of mobile. This
is
at io n de
WaP Architecture: nment for applic l.
an d ex t en si ble enviro mb le the layers of OSI mode
a sc al ab le Th e la ye rs re se
* It provides re d de sign 0 f protocol
stac k.
es an d applications
through a set of
achi ev ed us in g la ye ll as by ot he r se rv ic
transport
ac ce ss ib le by la yers above as: we ce ss se ss io n, transa ction, security and
* Each layer is
ac
e. External applic ation 5 may
well de fi ne d in te rf ac
layers directly.
 in Proto

Layer WAE)
aye Lae

hey ee

TLS-SSL
ee ane
San sennan AALS

_ TCP/IP

ture
Fig. 3.1: WAP Architec
; e over a variety of
ol s: de si gn ed to operat
WAP Protoc protocols,
cif ica tio ns def ine a set of li ghtweight
WAP spe clear
rer ser vic es. -b as ed (e. g-, SMS and USSD).It is
wireless bea ), or non-IP
es can be IP- bas ed ( e.g ., GPRS and CDPD
These servic characteristics.
y different QOS
S requirements.
ele ss bea rer s hav e ver
that the wir era te the se v2 ry in g QO
mpensate for or) tol
The WAP protocols co ed on
vironment (WAE): environme nt bas
Wireless Application En stack. It is gen era l pu rp os e
t layer in the WAP
WAE is the uppermos hnologies.
mb in at io n of WW W and mobile telephony tec tha t allows operators an
d service
co e en vi ro nm en t
is to achieve interoperabl
Its primary objective rea ch wide variety of wirele
ss platforms.
lic ati ons tha t can t can be used
providers to build app ge use d is WM L and WML script. WML scrip
addressing. Lang ua
It uses URL and URI for
input.
for validation of user
plication (WTA):
Wireless Telephony Ap P. It uses WTA Interface (WTA
l) which
te telephony services using WA
WTA provides a means to crea script.
L and for WML
can be evoked from WM es in device which can b e accessed
without
sib le to sto re WT A ser vic
The Repository makes it pos answer etc.
g the netw ork. The acce ss can be base d on any event like call disconnect, call
accessin by users The
ther e can be noti fica tion to user based on which WTA services are accessed
Sometimes,
d WTA service indication.
notification is calle
ol (WSP):
Wireless Session Protoc e WS?
id es rel iab le, or ga ni ze d exchange of content between client and server. The cor of
WSP prov
HTTP. All methods defined by HTTP 1.1 are supported
design is binary form of
d to agree o n common level of protocol functionality as well as to agree
Capability negotiation is use £
ona set of extended request met
hods so that full co mpatib+Lility to HTTP app
ppllicicaatitions can be retal i ned.
load 0
ork resources and can be resumed ad without over!oa!
An idle session can be suspended to free netw
WSP also
ishment. ous requests, Hence, multiple
ron asynch
full-blown session establ
. supports

air time.
requests will improve utilization of
(WTP):
Wireless Transaction Protocol : ‘
WTP is defined as light-we
i hin
ght-weight transaction-oriented protocol
suitable f or implementation int
clients.
 fa wrP - i security mechanisms and no
oe wire! ansport Laye: i set-up or tear-down phases.
yer Security (wr1s).explicit Connection
5 is5 ae protocol based on ind ):
port layer security betwee n @ WAP neustry
cli :
stand
ard t Transport layer security A (TLS). It provides
WA P Ga te wa y / Pro xy
; egrity, A ent and the
data int
, Te goals of f WTLS are protection. It has
4 am s upport, opt;imized
features like datagr
h cy, a uthenticatioatlic. n, Denial-of-service
Tiva
;
| andshake and dyn
ol (WDP):
| wireless Datagram Protoc
; mine ee
ee
{ » WDP provides application optional segmentation and reasse
mbly
& by port numbers,
optional error detection.
‘
, Itsupports :simultaneous com munication Ins
i tances :
: ieee a ee
pearer service. The port number identifies higher sel ae ve
abo WDP.
, The adaptation layer of WD P maps WDP functions directly on to a bearer based on its specific
characteristics. : On the GSMS z :
y is provided by WDP.
MS, data’
gram func tion alit
7. optimal WAP Bearers:
uit Switched D
» WAP is’ desi
The ,,
(cs0y
gned to oper.
GPRS, Unstructu perate over a variety of different service like SMS,’ Circ
a
: red Supplementary Services Data(USSD)’
WAP Programming Model
fos
» The similarity with WWW M odel, standard com ponents of WAP i
—ale -
functionality of WAP Proxy is described in following point
Similarity with WWW Model:

Internet protocol stack

stack
Language
WML: Wireless Markup
Ses sio n protocol
WSP: Wireless ! ‘
WTP: Wireless Transport Potoco
Tra nsp ort Lay er Security
WTLS: Wireless l Management
tro
WCMP: Wireless Con
Protocol I
gram Protocol
WDP: Wireless Data
ol Stack
Fig. 3.2: WAP Protoc ternet
ce s li ke ha nd -h el d ce ll phones to access the in
vi
ols that allow wireless de WWW.
WAP is a set of protoc to th at of
But it has programming mode 1 similar
content formats based on WWW
WAP content and applications are specified in a set of well-known
content formats
 Wireless and Mobile Network Wireless Application
3.6
° Transport of content is based on standard ich are b
communication aor nae that of
WW:
WhereverThe possible,
micro browser i Aliogonsipstaniierd ve uae
existing standards aes also some extensions to m
characteristics of wireless environment. are adopted, the benefits to application
This has provided be develope me
ability to use existing tools (e.g., XML sh
tools).
Standard Components of
Programming Model:
* Standard Sante bnhtraai 3 Soviet URLs identify WAP content on origin servers
ANd loc)
Tesources in a device (eg. Call
control functions)
* Content Typing: all si content has a specific type consistent with WWW content types,
Standard Content Formats: WAP content
formats are based on WWW technology and
display markup, calendar information, electronic Include
language,
business card objects, images and Scripting
Standard Protocols: The WAP communication
protocols and content types are optimized
market, hand-held wireless for mags.
devices. The protocols enable the communication of
from mobile terminal to network browser requests
web server.
Functionality of WAP Proxy:
* WAP utilizes proxy technology to connect
between wireless domain and WWW.
1. Protocol Gateway: It translates requests from WAP protocol
stack to WWW protocol stack,
2. Content Encoders and Decoders: The
encoders translate the content into
formats to reduce the size of data. compact encoded
Thus, mobile users can browse wide
Also,
application author is able to build applications variety of WAP content.
that run on large number of mobile devices,
3. WAP Proxy allows content and applications

art
to be hosted on WWW Servers and
to be build using

all
WWW technologies like ‘Cell global
identity (CGI)’ scripting,

cal
CLIENT —s

ii a
CHEUNG ORIGIN SERVER
: -| Tequest _21{ Requests

a
:
CGI
: ut : Scripts
~. -| Encoders |!

| |Responses
fn @ atc.

“| (content)
Br

Fig. 3.3: WAP Prog

ramming Model

_ Advantages, Disadvantages an
d Applications of wap
* Inthis section we will study advantage disadv s, antages an d applications —
Advantages of WAP: ;
1. Implementation near to Internet model,
2. Most modern mobile telephone devices s
Upport Wap,
3. Real-Time send/receive data.
4, Multiplatform functionality (little change is Nee
ded to run oo i
5. Nohardware obsolescence, on any website since XMI is used)
Advantages of WAP 2.0:
1. WAP 2.0 uses é ‘Cascading Style She
et (Css)’ Plus some
CSS2 which is language of Www. ; ; ‘ cet of
° WAP specific extensions, CSS is sub
2. With WAP 2.0, Web developers can use familiar a
building mobile Internet sites, 1s fot
Uthoring tools and PC web browsé
 Wireless Application Proto! i,

eth an eR
evap
=
Greater control on appearance of color

un
_ If there is only single Css to whole sit Sackground, berders, fonts, st site is first
visited. It is then stored in cache » Mobile will download it only once when the
tting j .
5 _ The
smaller ut and
layoand shortforma
Sv en palais can be moved to separate CSS which makes file size
, tapaieanialivinc hear me. Since the content and presentation can be separated:

devic ess easil

evice easily ame cont ent can be matc hed to characteristics of different wireless
and to different user agents easily
o The content file need not : market. Only layout
be modified when new mobile phones come to
is modified .
o Asingle WAP CSS can be applied to multiple
WAP pages.
o Thestyle code can be used in multiple projects
o Work on content and presentation can be divided.
pisadvantages of WAP:
4. Lowspeeds, security and very small user interface.
2. Not very familiar to users.
3, Business model is expensive.
4, Forms are hard to design.
s, Third party is included.
Disadvantages of WAP 2.0:
4, Different WAP browsers have different levels of support for WAP CSS.
first
required for a page to be completely loaded the
2, An external WAP CSS can increase the time
time WAP Site is Visited because of following Reasons:
mobile at first visit.
3, External WAP CSS style sheet does not exist in cache of
CSS have to be downloaded in separate requests.
4. An XHTML MP document and its external WAP
be large.
5, Ifasingle WAP CSS is used, the file size will
in addition to XHTML MP document.
6. The WAP browser needs to parse the CSS
Applications of WAP: :
the Internet from mobile devices.
4. The first and foremost application is accessing
devices over wireless devices.
t

Games can be played from mobile claims.

access time sheets and fill expenses
WN

Mobile hand-sets can be used to

very popular if implemented in secure way.
Online banking via mobile phones will be are
Services like locatingWAP customers geographically, providing weather and traffic alerts
up

ha
possible using WAP.

{ELESS MARKUP LANGUAGE) |

Ww limited
format for presenting data on devices with
* WML was designed to describe content and
limited user input capability.
bandwidth, limited screen size, and
uses, and other input devises common to mobile,
* Itis designed to work with telephone keypads, styl
wireless communication.
d in some small devices, as well
* WML permits the scaling of displays for use on two line screens foun
as the larger screens found on smart phones. the Hypertext
* For an ordinary PC, a web browser provides contents in the form of web coded with
Markup Language (HTML). ;
* To translate an HTML-coded webpage into WML with content and format suitable for wireles: s
devices, much of the information, especially graphics and animation, must be stripped away
 sir" web page and
capture the essence of
‘Wielies end Mobile

ML pre sen ts mai nly text bas ed info rmation that attempts t° rs
- "W y access for users of
mobile devices.
that is organized for eas limited
are P ro vided for text and
Features of WML: t commands
ag e su pp or t: Fo rm atting and layou
~ 1, Text and Im i
ividedided into sma ll, well-defined
image cap abi lit y. sub div
ts moving back and forth between cards. A
are
ard Org ani zat ion al Metaphor: WML ee
2. Dec k/C entry field). a
called cards. Users nav) : n of text, or a text
units of user interaction as cr ee
spe cif ies one or mor e uni t of interaction (a menu, by a web address (URL) and is the unit
card ntifie d
HTML page in that it is ide
WML deck is similar to an
dling,
of content transmission. rds and Decks provisions for event han
2 WM. L includes ML-based
g Ca web browser, a user
3. Support for Navigation Amon scr ipt s. In an
c utin g
which is used for navigation or exe
rough the
navigates by clicking on links.
with cards, moving
forward and back th
interacts elements are
At a WML capable mobile device, a user ch individual language
similar to HTML, in whi
deck, WML is tagged language, , : :
ine ate d by low erc ase tag s enc los ed in ang le brackets. h con tai ns
del visible portion, whic
ica lly , The WM L def ini tio n of a card begins with the non
Typ
t.
executable elements, followed the visible conten ed for
Scr ipt is a scr ipt ing lan gua ge wit h sim ilarities to JavaScript. It is design
WML Script WM L .
ipt -ty pe pro gra ms in a use r dev ice wit h limited processing power and memory
defining scr

(IMT 2000)
International Mobile Telecommunications-2000
ons-2000. An initiative of the
e IMT-2000 Stands for International Mobile Telecommunicati
wireless data networks.
International Telecommunication Union (ITU) to create a global standard for
support data
The goal of International Mobile Telecommunications-2000 (IMT-2000) is to
transmission rates of up to 2 Mbps for fixed stations and 384 Kbps for mobile stations.
Note that the “2000” in the term “International Mobile Telecommunications-2000” refers to the
transmission speed (approximately 2000 Kbps), not the deployment date (which might be several
years beyond the year 2000). .
The European proposal for IMT-2000 prepared by ETSI is called as Universal Mobile
_ Telecommunication System (UMTS).

twee Features
The features of IMT-2000 are as follows:
1. Itis used for all radio environments.
2: It supports both packet switc
i hed and circuit switched data transmis
sion
3. Itoffers high spectrum efficiency.

3.2.3 | IMT 2000 Architecture

IMT-2000 is a 3G wireless co
mm unications standard def
International Telecommunic ined b y the recommendations of the
ation Vision (ITV).
Fig. 3.4 shows the IMT 200
0 archit ecture.
The ITU standardize 5
—_—

Broup of 3G for radio access

technology.

a
 pS:
itis used the direct spread technology,
itis also called Wideband CDMA.
itis part of Third Generation Partnershj j
hero ership Project (3GPP).
ituses Time Code Technology,
itar-MC:
further divided into 2 standards TD D and TD-SCDMA.’
5

ituses Multi Carrier Technology.

uesis multi carrier technol
CDMA ogy and ititi is part of SGPP2,
it uses Single Carrier Technology.
Itis enhancement of US TDMA System
IMT-FT:
Ituses Frequency Time Technology.
Itis enhancement version of the digital cordless telephone standards DECT.
IMT

Ufpaires spectrurt
spectrum

{MT-DS
W-C DMA
(UTRAN FDD)
Direct
Spread

TDMA
Fig. 3.4: IMT 2000

System
wea IMT 2000 (CDMA 2000) the United National (UN) organization
n Union (ITU),
International Telecommunicatio working since 1986 toward
The standards, has been
telecommunica tion
n
for global to worldwide telecommunicatio
responsible standard for wireless access
developing an international

infrastructure. IMT 2000 or International Mobile Telecommunications 2000 (2000

as
This standard is known 2000 as wellas the operational frequency
band 2000 MHz range).
indicates target availability yer? ration (3G) mobile telecommunication system which exhibits the
gene
IMT 2000 defines the third
following characteristics: rvice delivery.
and sé ication services
1. Seamle ss glob al mobi lity
nd wi re le ss ne tw ork to provide telecommun
wire line a
2. Integration of the
the users: and to allow current
transparently to andards ou gh to me et lo cal needs stem
3. Defining global st that are flex ib
towa
le en
rds third generation sy
.
ems to evolve smoothly
regional/national syst
a
Wireless and Mobile Network

and its capabilities are:

© The vision for an IMT 2000 system 2-2.2 GHZatpand) ,
worl d-wi de (1.8 GH ellite s
Common spectrum
em data, multimedia and internet)
Multiple radio environment (cellular,
Nn P

cen
Wide range of telecommunication services
Flexible radio bearers for increased spectrum et".
oO 9 nowy

environments
Data rates up to 2 Mbps for indoor
Maximum use of IN capabilities.
Global seamless roaming.
.

Enhanced security and performance. i

. Integration of satellite and terrestrial

systems. mmunicatig,,
1 ra ng e of mo bile and personal co
IMT2000 service environme nts will address the fu
application.
The scope of IMT2000 services include:
1. Inbuilding (picocell).
Urban (microcell).
win

3. Suburban (macrocell).
4. Global (satellite).
data and images. ©
5, Communication types that include voice,
Radio aspects of IMT2000 are:
1. Uplink frequency: 1885-2025 MHz
2. Downlink frequency: 2110-2200 MHz
and TDD for indoor and pedestrian
3, Transmission mode: FDD for mobile and satellite applications
type applications.

Global

Satellite ,
Subarban

Batic Terminal
PDA terminal
audio visual terminal

000 Sys em
A significan t element of IMT 2000 is the need po m
to sites e
efficiency compared to the currently available in the 2g mobil Se ee ores :
sharin € communication. wee
In context of managing the access the spectrum,
6 & common pool of spectrum be <
operators and/or between terrestrial and satellite services is
Key Features of the Radio Access for IMT 2000 are: used to improve spectrum efficien:
1. High level of flexibility
2. Cost effectiveness in all operating environmen: is
 [Sas
.
Mobile Network Wirelese Appiloation Protocol..
3

agg rsge
=
3. commonality of design worldwide
4. Operation within the designated IMT 2000 frequency band
global radio channels are scanned by IMT terminal to find the required information on available
networks/standards and services.
qhese channels carry information like bands used for IMT 2000, frequency rasters, modulation
characteristics, guard bands, duplex direction and spacing, list of application services etc.
Implementation of IMT 2000:
in
asa stand-alone network with gateway and internetworking units towards supporting networ ks
cular towards PSTN, ISDN, and Packet DATA Networks.
radio
it may be integrated with the fixed networks. In this functions needed to support specific
are conn ected directly to a
network requirements are integrated to the fixed networks. Base stations
integrated functions and by accessing
jocal exchange that can support IMT 2000 traffic by locally
functions in other network elements.
support of multimedia services. IMT
Requirements for network functions must take into account the
concept.
2000 system should support global roaming and virtual home environment

epee -
MT 2000 Service and Network Capabilities: up to 384 kbps
144 kbps in vehicular radio environment,
Circuit and packet bearer capability up to ent.
2048 kbps for indoor and office radio environm
for pedestrian radio environment and up to
y of systems.
Interoperability and roaming among the IMT 2000 famil
ent.
Service portability and support of virtual home environm
Multimedia terminals and services.
Emergency and priority calls.
connection control.
Separation of call and bearer channel/
User authentication and ciphering.
authentication.
User-network and network-network
ce.
Geographic position/location servi
surveillance.
Lawfully authorised electronic
tions by the ITU:
IMT 2000 Interfaces for Specifica vide
sys tem s bel ong ing to diff eren t IMT 200 0 family members can interoperate to pro
* Toensure that
service delivery.
seamless global roaming and of layer
ires the spec ific atio ns not only of the physical radio interface but also
requ this
protocol that may be required across
* MT-RAN interfac e
some supplication
2 and layer 3 protocols as well as support
interface.

MT-RAN RAN-CN
itt interface
intertace intertace
Sa
ee
ts cae

phases
in ied
To be specif

CN Core Networt
ITU
em interfaces for specification by the
Tig. 3.6) DHT 2000 family member syst
use RAN-CN
family systems operators may prefer to
ln the inidal implementslion of IMT 2000
*

intertace based on existing wireless PCS systems

 . ‘) ;
mod ]
identity
Wireless and Mobile Network le user
nm removab
petw ee.
the interface
“ee repr esents
IM- interface ; networks belo, og
mobile terminal. . global roaming
interface for supporting across i :3
The CN-CN interface is key in 3
different family members. }

cweee isi
IMT 2000 Vision : i servi
demand for mobile : ice in the twenty. am
rket
IMT-2000 is a global standard to satisfy ma
century. . ilities Bani T:
The rs for IMT-2000 system services and its capabili is as unde
Common worldwide spectrum. rdless, cellular).
Se

Multiple radio environment (LAN, satellite, co

Worldwide roaming capability.
ee)

High quality, enhanced security and performance.

Small terminal for worldwide use.

i
Oe

Integration of satellite and terrestrial system.

Se
ene eet EITETE TSN STN
Ee WIDEBAND COD: )IVISION MULTIPLE
ACCESS (WCDMA) » a
WCDMA stands for Wideband Code Division Multiple Access and is the 3G technology that employ
the Direct-Sequence Code Division Multiple Access (DS-WCDMA) channel access method and th:
Frequency Division Duplexing (FDD) method to provide high-speed and high capacity service
Third generation (3G) wireless capability has been developed in response to a growing
demand ft
data services,
There are several different radio access technologies defin
ed within ITU, based on either CDM ©
TDMA technology. Different regional solutions were
proposed as solutions to the requirements of
IMT-2000,
These included Time Division Multiple Acce 1a
ss (TDMA) and Code Division Multiple
utilizing Frequency Division Duplex (FDD) and Time Divi
sion Duplex (TDD)
Access (CDMA)|
The fragmentation of the Proposals a
led to the creat;
the Third Generation Partnership Project
(3
Telecommunication Standard (UMTS) base
d on WCDMA.
The other group is known as 3GPP2
works on ¢ DMA 2000 4
Organization 3rd Generation Partnershi i
fulfils the mt-2000 i
mobile system that
en oe a
continued that work
Telecommunication System (UMTS) by defining
* ous system a called Universal Mobil”
ITU finally approved a family of
fi ve 3G st
IMT-2000. These standards are: andards Which
are Part of the
_ WCDMA (UMTS 99) 3G framework kn
own
WCDMA (Hspa)
PWNr

CDMA2000
TD-CDMA
5. TD-SCDMA
\ WCDMA Features Two
Modes:
1. Frequency. Div
ision Dup le
frequencies. One frequenc xis (FDp),
y Used roe arately Users b
© Uplin I, while y mploying both codes as ’
walt
a | i ther js used for downlink - a
 usersandbyd em Pos
tes link codes, frequencies and time wherein
Nn timin chro:
to provide support of mu fican
ltiple users it tes Pendteent data
Esai rate,s. Thhe
e fl
aexsibtileityy necessca
rms for Validation itin
atees ta
the
and test.

» code Division Multiple Access 2000

additional functionality that increases
code Division Multiple Access isa
its spectral efficiency and data rate capability.
mo bile digital radio technology where channels are defin
ed with
codes (PN Sequences).
+ CDMA permits many simultaneous transmitters on the same frequency channel. Since more phones
can be served by fewer cell sites, CDMA ~based standards have a significant economic advantage
over TDMA or FDMA-based standards.
+ This standard is being developed by Telecommunications Industry Association (TIA) of US and is
standardized by 3GPP2. The main CDMA 2000 standards are: CDMA 2000 1xRTT,CDMA 2000 1xEV
and CDMA 2000 EV-DV,
CDMA 2000 1xRTT:
¢ RIT stands for Radio Transmission Technology and the designation “1x” meaning “1 times Radio
Transmission Technology”, indicates the same RF bandwidth as IS-95.The main features of CDMA
2000 1X are as follows:
1. Supports an instantaneous data rate up to 307 Kbps for a user in packet mode and a typical
throughput rates of 144 Kbps per user, depending on the number of user, the velocity of user and
the propagating conditions.
2. Supports up to twice as many voice users a the 2G CDMA Standard.
battery life.
3. Provides the subscriber unit with up to two times the standby time for longer lasting
CDMA 2000 EV:
the following characteristics:
* This isan evolutionary a dvancement of CDMA with
the options of installing radio channels with data only (CDMA 2000
1. Provides CDMA carrie rs with EV-DV)
ce (CDMA 2000
EV-DO) and with data and voi ket
1xEV-DO sup por a
ts greate r than 2.4 Mbps of instantaneous high speed pac
2. The CDMA 2000
channel, a ough the user data rates are much lower and highly
throughput per user ona CDMA
dependent on other factors. as many voice channels
data rates up to 144 Kbps with about twice
3. CDMA 2000 EV-DV can offer
as IS-95B.
CDMA 2000 3x: : :
mu
Iti-carrier evolution. It has higher rates per carrier (up to 4.9
Rev B) isa
* Itis (also known as EV-DO
are
rate of 14.7 Mbps. Higher rates
ee include 3 Carriers for a peak
: oe
It enhances the user experience and enables new
H ae
together.
Possible by bundling mut!ae channels
Sn . ee ee ea ae
Sani
services such as high definition ot.
console sessions and web
ratietica multiples en as gaming, video telephony, remote
at
or latency-sensitive service:
browsing.
 14 ;
Wireless and Mobile Network s a
from the adjacent F
* It provides increased talk-time and standby tim? ime. The interference
tes that can be offered, especially tg, ¥h
|!

reduced by hybrid frequency reuse and improves the rate User y

the edge of the cell.
do wn lo ad an d upload requiremen
. : s tha t have asymmetric
It has efficient support for service chas file transfers, web browsing, and broad
different data rates required in each direction) su
multimedia content delivery.

CDMA 2000 Evolution Path _— seen dots sullstion tre '

CDMA has single upgrade path for eventual 3G operation. is. The original IS-95 through Cb
*
called I-95B, 18-95 channel can support up to 64 user channe's- PUt rateoy
9600 bps was improved to current rate 14400 bps.
The eventual 3G evolution for CDMA system leads to CDMA 20 00. Several
variants of CDMA 209
* Oan |
ae
currently developed but they based on fundamentals of 1-95 and IS-95B
* The eventual 3G evolution for GSM, IS-136 and PDC system leads to Wideban (WCDMA), als
called Universal Mobile Telecommunication Service (UMTS). |
* WCDMA is based on the network fundamentals of GSM as well as the merged versions of GSM ands.
136 through EDGE.
© CDMA2000 standard is based on CDMAone system and allows to access internet by using wireles, |
carrier with high data speed. In the year 2002 the first CDMA 2000 system was offered anj |
standardized by 3GPP2 (3rd Generation Partnership Project 2). |
* It is especially used in North America and South America and South Korea. It shares jt,
infrastructure with the IS-95 2G standards. To improve the performance of existing system, the
CDMA 2000 does not use any extra equipment. It just only changed the software or hardware of the |
' existing system.
e The CDMA 2000 is more advanced than the CDMAone as it serves the twice number of users than _
CDMAone and the battery life of mobile station is twice as compared to CDMAone. It also provides —
high speed data access by using packet data transport.
e CDMA 2000 is seamless and less expensive as compared to W-CDMA. CDMA 2000 also known as IMT:
CDMA. Multi-carrier is a CDMA version of the IMT-2000 standard developed by the International
Telecommunication Union (ITU).
* CDMA 2000 is a set of standards that define the new air interface and changed in radio access that
will enhance the network capacity, improve data speed and bandwidth of mobile terminals and alse
allow end-to-end IP services.
e In early 1990s the application of CDMA technology was introduced
in cellular system with |
development and characterization of IS-95 standard, The CDMA 20 00 technology is developed fro
IS-95 with significant enhancement in voice capacity, data speed ra
te and network features.
e The 3G system implement soft handoff when MS moves from on
e location to another to overcome
the problem of near far terminal. ,
* CDMA 2000 is backward compatible with IS-95 that inch tt
family reuses the existing IS-95udeservice
enhanc ement
jena in access and
a trafficst
cat et ®™
handoff. The CDMA 2000
speech services, Short Message Services. ards such as thos
e Data rates of up to 150 kbps or 300 kbps is provid fe
: ed that d ‘ graff |
channel radio, enhanced channel coding with turbo setae on the configuration . tbe
increased mobile terminal battery life with the introduction of = igher data rates are rs
e All above features = = in CDMA 2000 to provide a voice on pam oe = oft
CDMAone systems and data rate of 153.6 kbps or 307.2 iowa Pé city that is twi agai?
used. €pending on the radio con! .
 the noise. ,
three main CDMA 2000 standards are.
4, CDMA 2000 1Xrtt
2, CDMA 2000 iXev
3, CDMA 2000 EV-DC
CDMA 2000 1Xrtt support both voice and data services over the standard 1.25MHz CDMA channel.
The 1x in the name signifies that it uses one 1.25MHz channel. Due to improved modulation, power
control, and overall design, it can achieve theoretical data transfer rates of 144Kbps
There are two members of CDMA 2000 1Xev Family:
1, CDMA2000 1x Evolution Data Optimized
2. CDMA2000 1x Evolution Data and Voice
The CDMA2000 1x EVDO supports greater than 2 Mbps of instantaneous high speed packet
throughput per user on a CDMA channel, although the data rates are much lower and highly
dependent on other factors.
twice as many voice channels
The CDMA2000 1x EVDV can offer data rates up to 144 kbps with about
as 1S-95B. :
can provide decreased latency and a reduced
Base station timing synchronization in CDMA 2000
: i andoff.
cat pon ye have been simultaneously adapted for the 3G standard,
ne SE
becomes mpeseneyy fomake eisai Sere eee
harmonization of these two systems
3G CDMA specificatio n and process the separate W- an
Tb Greate a single integrated
2,
Proposals being developed by SGPPand ae

nts of CDMA 2000

riesgumcomPpon®
 \ee
and“é WCDMA WCDMA is a 3gtay
Comparison of CDMA 200" _95 CDMA technique.
© CDMA 2000 is a 3G technology evolved fro
evolved from GSM technology.
Table 3.3_tS Sey ee

CO CMMAP
ary

Core network ANSI-41. MAP mer 5.0 MHz > ee

Channel bandwidth 1.25ani (na. = 4-256 i
i 4-128 (1X), 4-
Channelization
Chip
codes masa Mops (IX), 3.6864 Meps | 4.096 Mcps (DOCOMO), 3 y=
rate - (UMTS) — a
No; but synchronizeg
Synchronized base station Yes BS
Optional

Frame length 5 ms (signaling), 20, 40,

80 ms 10 ms for physical layer, 1935
physical layer frames 40, and 80 ms for transpo,
Layer a
Multi-carrier spreading option | Yes, but in cdma2000 1X (direct | No (direct spread)
spread) oe
Modulation QPSK (forward link), BPSK | QPSK (both links)
(reverse link)
Modes of operation FDD FDD and TDD
Source identification code for One PN code (32,768 chips),512 512 unique scrambling code,
Sector unique offsets are generated, each identifying a sector,(38,400
using PN offsets chips)
Source identification code for | One long PN code (242242) | Unique scrambling codes,
Mobile chips, unique offsets are assigned by sector
generated, based on ESN, not
assigned, by sector sea)

Quality of Services in Third Generation (QoS

in 3G )
e Network Services are considered end ieee. this mea
ns from a Terminal Equipment
TE. An End- to-EndServi may have
ce
(TE) toandbé
of a network service.
; ne Quality of Service (QoS) which is provided for thew!
e Itis the user that decides whether he is satisfied
with the
network QoS a Bearer Service with clearly defined Provided Qos or not. To realise 4 cet
ch afacteristics and functionality
from the source to the destination of a service. is to best!

* AUMTS bearer service layered architecture js depi

offers it's individual services using services pr
Ovided by
* There are four different QoS classes namely, the layers below, '
and Background class.
Conversat 1onal Class, Streaming class, interactiv®
 See?
Tec eacencres eae

pundament al ierstime
tTeserve : Real Tim
< —_—
Best Effort vss
i hie (tals
eiteai
ff
eer

characteristics relation
bk ( Ses
Variation) Preserve
relation (variatitim © | Request response | best er is not
Destination
we tween . between On) | pattern expecting the data
information i within a certain
entities of th, nformation time
| enti
eee stream erie of the
| m
Conversational |
pattern (stringent Preserve payload Preserve payload
and for delay) content content
Example of the | Voi
P ake Streaming video Web browsing Telemetry, emails
application

Si Rey as
« UMTS stands for Universe of Mobile Telecommunications System. To handle a mixed range of traffic,
a mixed cell layout that would consist of microcells overlaid on microcells and picocells is one of the
architecture plans being considered.
* This type of network distributes the traffic with the local traffic operating on the microcells and
' picocells, while the high mobile traffic is operated on the microcells. Thus, reducing the number of
hand-offs required for the fast moving traffic.

cee UMTS Features

* The features of UMTS are as follows:
1. Bandwidth : 5 MHz or 1.25 MHz.
Chip rate : 3.84 Mcps.
.
Frame duration : 10 to 20 ms (frame length)
of

Data rate : 2.048 Mbps.

Frame structure : 16 slots per frame.
Backward compatibility : GSM.
NS

MHz.
Power control frequency : 1.5
Asynchro nous.
Base station synchron ization:
{oo

Data rate: up to 144 Kbps.

na.
. Antenna used: Simple Anten MHz.
4920 to 1980
. Frequency spectrum: Uplink
BEES

Downlink 2110 to 2170 MHz.

TDD modes.
. Duplexing Technique : FD Dand ‘A with QPSK.
quence CDM
14, Modulation scheme : Direc t se a ding Factor (OVSF).
gonal variable Spre
1S. Coding Technique: ortho iservice.
16. Service type : Multirate and multiserv}
 Wireless and Mobile Network $.18 soe Appileation Protooy < 3A
ceva UMTS Network Architecture %
3
* With the changes from 2G to 3G,the emphasis for the systems changed from focus on mobile Volcy 4
communicationsi to mobile data and general connecti vity.
* The foundation for the UMTS network had been set in place when GSM was launched. This Provided
the basic access elements as well as circuit switched voice.
* The additional network entities to be added it was the combination of these two network element
is for 3G UMTS network architecture. ;
s ge a _ divided into a set of domains and the reference points that interconneg
them.
The UMTS network architecture is partly based on existing 2G network components
and some new
3G network components, It inherits the basic functional elements from the
GSM architecture on the
Core Network (CN) side,
The MS of GSM is referred as User Equipment (UE) in UMTS.
The MSC has quite similar functions
both in GSM and UMTS. Instead of circuit-switched services for packet data,
a new packet node SGsn
is introduced. This SGSN is capable of supporting data rates of
up to 2 Mbps.
The core-network elements are connected to the radio network
via the Iu interface, which is very
similar to the A-interface used in GSM.
The major changes in the UMTS architecture are
in the Radio Access Network (RAN), which is also
called
UMTS Terrestrial RAN (UTRAN). There is a totally new
interface called Iur, which connects two
neighbouring Radio Network Controllers (RNCs). BSs
are connected to the RNC via the lub interface,
UMTS Terrestrial RAN (UTRAN)
* UTRAN consist of Radio Network Subsystems
(RNSs). The RNS has two main elements:
1. Radio Network Controllers (RNC)
2. NodeB
1. Radio Network Controller (RNC):
The RNC is responsible for control of the
ra dio resources in its area. One RNC controls multiple
nodes B.
* The RNC in UMTS provides functions
equivalent to the Base Station Contro
GSM/GPRS networks, ller (BSC) functions in
The major difference js that
RNCs hav € more intelligence
counterparts. For example, RNC built-in than their GSM/GPRS
s can auton omously manage hand
SGSNs, over s without involving MSCs and
2. NodeB:
° rial Node B is responsible
for air-interface processing
‘unctions, © and some radio-resource
management
The Node B in UMTS ne :
tworks provides functi
GSM/GPRS networks. UM ons equivalent to the bas
TS operates at higher fre e transceiver station
(BTS) in
coverage range is less, que ncies than GSM/GPRs
and therefore the signal
Features of UMTS Interfaces;
* The UMTS interfaces
can be categorized as fol
1, Uuis the interface between lows;
:
The equiva . the user equipment and th € network. That is, j
lent interface in GSM/ i erfac a
r int
2. The luis split functionally into twGPRS networks is the um interface eee
0 logical interfaces, Jups
the access network and the lucs connecting the circ i : i ain to
ia oneal

standards do not dictate that these uit Swit

tchi
edldoma
dain ito th
s e c an
are physically separ e access t
network. The
and the control plane may be different, te,
ren t
ate, but the user plane for each is diffe
 domain

USIM
Domain E iis Access Servin Transit
Domai rf Network Newer Network
n Domain Domain Domain

—— User equipment domain»

+—— Core network domain ———*

“—— Infrastructure domain ———

I OR)
: Network subsystem '
Motte station 1 Base station subsystem Other networks
!
a \ f " —\ ! !
1 I
! ‘BSS | i 1
| 1 |

SIM — 1
1 |
' 1
|
I
! I
I !
Cy | !
I 1 I
!

GGSN
uy m
SCN ee —1
| | Internet }°
ri I CEES Ahan:
I
\
» i

. I : = : x S . !
!
I oe MINES I
1
I' 1 i
!
' 1
1
; !
1
; 1

! | i
|
! SpA
I
| I
|
! 1 |
| 1 '
! 1 1
' \ |
I 1 '
| '
' lu
Uu
Fig. 3.8: UMTS Architecture
ete pi

lu-cs; cally) voice traffic and signaling between

ed co nn e ction for carrying (typi ff
circuit-sw it ch ‘,
This is the e network.
the UTRAN and the core voic Network Application Part (RANAP). The equivalent
ee

Access
The main signaling protocol used is Radio
ae

ce.
rks is the A-i rfa
nte
interface in GSM/GPRS netwo
 sign naling protocg) ae
e Bs. | The mainin sig
ss poy
3¢ a This is the interface u sed by i: an RNC to control multiple Nodpis interface. The lub int
i erface is= then. t : ‘1 a;
nae is the A-
orks
Node B Application Part (NBAF).
a
The equivalent interface in GS
standardized and open, unlike the A
Tu -PS: :
This is the packet-switch networks ‘ :
work. sivalent inter face in GSM/GPRS
UTRAN and the core data GPRS net
d is RANAP. The ed
The main signaling protocol use
Gb-interface.
subscribe
Tur:
po rt in te r- MS C mo bility. When a mobile
ace is to uP
The primary purpose of the lur interf le subscriber's data is now transferr
ed j,
moves between areas served by different RNCs, t
he mobi
the new RNC via ur.
the new RNC is known as the drift RNC.
The original RNC is known as the serving RNC and
Network Subsystem App lication Part (RNSAP). There ig no
The main signaling protocol used is Radio
equivalent interface in GSM/GPRS networks.
!
I
ene I
= Node B s I
te eet his I
PSTN/ISON

Node B- |
Pa? ote l
lee

!
1
: ar bss Soo ae

Node 5 & ERNC. 3 Packet data

to ; | network
! G
'*+— Access : network domain ————»}<«—__ if
Core network domain a
Fig. 3.9: UMTS Architecture
Applications/Advantages of UMTS
The applications of UMTS are as follows:-
Benefits to Consumers:
1. Send picture messages to other mobile
phones
2. Download the latest games and Pol
yphonic rin,
3. View news bulletins, sports highlights and a, t ones,
4. Experience video telephony. SIC Videos Streame d to their mobile handset.
List of Possible Type of Services that
willb €
1. Fun: WWW, video, post card, snapshot Available j
s, te n3G Networks.
personalisation applications (ring tone ing xt, picture and mu
2. 2Work: Rich call with image and dats 1 eeVe desk top) ltimedia messaging,
gata"
d
information exchange, personal informa Stream, yp tele ‘duke box, virtual companion! rs
on ma Nager, daj Phony,B2p ordering and logis? 0
"Y; Scheduler, note pad,2-way « i
 ; ~ eonferencing, director
y sexi
Ces, travel as
eree: a Sistance, work group, t telepresence, FIP, instant
P,
tip Media: Push newspaper and m
3 agazi
4. shopping: E-commerce, e.cash, own
a

guction, microbilling shopping allet, credit card, tele-banking, automatic transaction,

5,. En gntertainment: News » Stock market, sport
adult content. $ games, lottery, gambling music, video, concerts,
~ gducation: Online libraries .
attendance, field
1; peace of Mind: Remote
ae s urveillanc locationremote
arche,engines, tra ki rae ee
8. Health: Telemedicine, remote diagno Ree ike
e auto mati on ‘ as healt h monit oring .
g, Automation: Hom *
machine communication
(telemetry). » traffi
| affic telematics, machine-

l: location sensitive informati lon and guidance, e-tour, location awareness, time tables, e-
40. Traveing:
seat

41. Add -on: TV, , radiYadio, PC, access to remote computer,MP3 player, camera, video camera, watch,
pager, GPS, remote control unit.
penefits to Operators:
4, Automatic international roaming.
2, Integral security and billing functions.
3, Retaining many of the existing back-office systems.
to business users and consumers while
4. Flexibility to introduce new multimedia services
providing an enhanced user experience.
revenues.
er dem and for valu e adde d serv ices and a corresponding increase in
: High ting 2G networks are facing
wn

more cially in urban areas where exis

subscribers-espe
6. Support
acon y
limitations. order to enable new multimedia services
40 times higher than GPRS in
7, Offer data speed up to
such as video telephony. mobile service operators
ment GSM/GPRS,3G/UMTS offers
s in
8. Building on current invest capab ilities to suppor
t greater number of voice and data
ty and bro adb and cost than 2G.
significant capaci her data rate at lower increm
ental
oing on to ac hieve throughput speed beyond 3G
custom ers-especially in urban areas-plus ue
ne
9. Various research’ and development work is go'
UPA. . true
‘ S as a key enabler for
Soon instrament role in positioning 3G/UMT
esee logiesSa
technoasi will p
pana f same order of magnitude as ea Ethernet based networks
=a broadband ’.
ission $ dband services.
erin connectivity —
that Scant useabt the fixed line operators to nsu
Pe lm ll the benefits of broadband
ee
3G/UMTS will offer enterprise customer _ ees oe
Whilst on the move.
+ ORAS cent
ee ee
monomers jC
sete ENERA (RG) obile communications will have
TION The 4G m
= rate plus yoice system.
aa
* 4g (2013) is a high speed aa : tha n that
of 36.
higher
tex up to 20Mbps
transmissi =
 ally with lower Cost,
Joba l ro amin g univ ers
ry smooth 6 ally and up to 1Gpbs to,
pe ct ed to pr ov id e ve ile devi ce glob
* 4G technology is ex
r 400 Mbps to 8 roaming pin
Theoretically 4G is set to delive : king called WWWW (Worldwide
stationary device. wor ld wir ele ss int ern e twor
perfect real
¢ 4G will bring almost streaming picture perfec
encing,
Wireless Web). ws fo r vi de o confer
e With the expected features in
min d 4G allo a and much more.
e-geo processing application and code Division Multiplexing (vsp.
video (eg. tele-medicine and tel
e 4G uses variable spreading factor-or
thogonal ‘=frequency ‘
Acces s
(VSF-CDMA).
ding Factor Code- Divis ion Multi ple
OFCDM) and Variable Sprea
4G Features: bandwidth and services
technology with more
© y basically the extension in the 3G
4G technologis
offered in the 3G features of 4G are:
e, str eam ing vid eo, internet and other broadband
edi a, voic
1. 4G support for interactive multim
services.
:
2. 4Gis IP based mobile system.
low cost per Dit.
3. 4G has high speed, high capacity and
able mobile services.
4 . 4Ghas global access, service portability and scal
en services.
5 and a variety of Quality of service driv
AG has seamless switching
control techniques.
6. 4G has better scheduling and call admission
4G cellular systems is shown in table.
A short history of cellular evolution from 1G to
Table 3.3

ea : 2.5G
1985 1990 2000
Design began
1984 1991 1999 2002 2012-2015 _|
Implementation
Service Analogue Digital voice | High-capacity High- Higher
voice packets, MMS capacity capacity,
broadband completely
data IP, |

Multiple Access FDMA TDMA, CDMA | TDMA, CDMA CDMA eS |

Standards | AMPS,TACS, | CDMA,GSM, | GPRS,EDGE | wcpMA ce |
NMT :

1.9 Kbps fami 384 Kbps SP RA 2000 standard |

| Bandwidth
PSTN PSTN 2Mbps 200 Mbps —|
| Core Network Packet Internet
PSTN,
Packet network network: ae

|
ce-we VOLTE and its Features
* It is-a standard for high speed wireless
wi com: i on for mobile phones and data terminal’
including IOT devices and wearables, ili
e It is based on the IP Multimedia Subsystem
netwi and medi?
planes of voice service on LTE defined by GSM rk, with specific profiles for control
in ea DIR.gz.
° Vaire over Long Term Evolution (VoLTE)
is a st
mobile phones and data terminals -including lotTM tate for high speed wire less communicatio? fof
nternet of Things) devices and wearables.
 oui sale el tes? Vy
e 5 and Mobile Network

ne
3.23

jg based on the IP Multimedia subsystem network with isspecific profiles for control and media
me (Long Terma standard for high-speed wireless
Evolution)
ye planes of voice service on LTE
defined by GSMA (Global System for Mobile
communication for mobile devices and data terminals
association).
3,10 shows architecture of VoLTE system.
» Fig HSS

ENODEB
a
=. @®) MME

lod
S/P-GW
Control
Access Evolved packet core

izzae
aie
Fig. 3.10 : VoLTE System Architecture
ENODEB : Evolved Node B.
MME: Mobility Management Entity.
s/P-GW : Serving/PDN(Packet Data Network) Gateway.
HSS: Home Subscriber Server.
IMS : IP Multimedia Subsystem.
PCRF : Policy and Charging Rules Functions.
handle cellular voice calls over LTE. Most major
* Voice over LTE(VoLTE) aims to provide the ability to
least begin to deploy VoLTE within the next
network providers have a nnounced their intensions to at
couple years.
VoLTE Features:
the terminal and IMS.
1, Setupo f the transmission path between
a tion providing.
2. Security features for user authentic
t he establishment and termination of the call(via SIP).
3, Providing the core functionality for
g ,caller ID present ation and restriction, call waiting and multiparty
4. Support to call forwardin
conference.
traffic.
5. Designed for both voice and data
ee

s of VoLTE
Ey Advantages and Disadvantage
s VoLTE are as follows:-
* The advantages and disadvantage of
Advantages of VoLTE:
sa

ices over same network. Hence it does not require to maintain

1. It delivers all voice and data serv
ae

legacy infrastructure.
to 2G/3G voice calls.
VoLTE make calls much faster compare
gens

It offers better security and QoS (Quality of Service) compare to legacy 2G/3G networks.
pwn

» Delivers an unusually clear calling experience.

5. Provides rapid call establishment time.
 ay
“a5

3.24

Wireless and Mobile Network

ence thi*s wil* l no t be available everywhere ang |
Disadvantages of VoLTE:
k wide ire ‘
1. It dia investment in networ be ab le to call nor we
i ‘a the are user will neit he r
hence roaming could be challenge4Gorsignaling
tion or
2, If there is no data connec apeain Vv LTE feature is
t. oLTE services. The VO
to use internet using handse
by handsets in order to
3, VoLTE should be supported
handsets.
not available in all mobile

Co mm un ic at ion ( 5G)
Next Generation of Mo bi le ta rate are Pushing
data and higher da
—_—
n
icatio n, The next or fifth generatio
¢ The rapidly increasing number of mobile devices, van
cellular mobile Sate
to rethink the current generation of the high end requirements. «
5G cellular networks are expected to meet ubiquitous connectivity,
unique features:
e The 5G networks are broadly characterized by three
;
Extremely low late ncy and very high speed data tra nsfer. e of mobile
entl y unde r deve lopm en ¢. It denotes the next major phas
ed standards.5G networks will
e 5G is a gene rati on curr
beyo nd the curr ent 4G/I MT Adv anc
telecommunications standards as broadcast like
such as Internet of Things (IoT) as well
also need to meet the needs of new use-cases is
of disaster.
services and lifeline communications in times bandwidth,
the means to use cellphones within very high
® 5G (2021) mobile technology has changed
of the cellphone (mobile) technology. The 5G
* Now days mobile users have much awareness
5G mobile technology most
technologies include all types of advanced features which make
powerful and in huge demand in near future.
Features of 5G:
1, The5G technology is providing up to 25Mbps connectivity speed.
2. 5G technology offer high resolution for crazy cell phone user and bi-directional large bandwidth
shaping.
3. 5G technology also providing subscriber supervision tools for fast action.
4. The advanced billing interfaces of 5G technology makes it more attractive and effective.
5. The high quality services of 5G technology based on policy to avoid error.
6 . The traffic statistics by 5G technology makes it more accurate.
7 5G technology is providing large broadcasting of data in Gigabit which supporting almost 65,000
. connections.
8. The remote diagnostics also a great feature of 5G odinslogy.
9. 5G technology offer transporter class gateway with unparalleled consistency
0 ae remote management of ‘oes by 5G technology a user can get better and fast
solution.
. The 5G technology network otfering enhanced and available connectivity just about
the world.

kere 4G Architecture
* 4G stands for fourth generation cellular system, 4G
demand. is evaluation of 3G to meet the forecasted rising
s It is an integration of various technologies inclu
MT-2000 Wireless LAN. Dat@
rate in 4G system will range from 20 to 109 Mb ding GSM,CDMA,GPRS,I
i ps.
Features:
1. Fully IP based Mobile System,

; : : i 8 V i deo inter
5 i
 ~ thas better spectrum ef ficiency,
> seswpports Ad-hoc and multi
hop network
architecture:
ag 3,11 snecus
shows Gene ric Mobi
wittless. le Com sine
acceas muni Ca tion| architecture.4 G network is an integration of all
an tks such as Ad-hoc, cellular, hotspot and satellite radio
ologies used in 4G are smart an
' yolP, OFDM and Software Defined
widic aes bay peenieen caer
cpstt antennas: i Til
‘
Antennas are Transmittin & and receiving
‘ rrdoes not require increase antennas,
pow: er and additional
frequency.
gre Technolgy:
, aguses IPV6 Technology in order to support a large number of wireless enable devices.
, nenables a number of application with better multicast, security and route optimization
sates :
capabilities.
volP: :
, Itstands for Voice over IP,

He
s Itallows only packet to be transferred eliminating complexity of 2 protocols over the same circuit.
OFDM:
« OFDM stands for Orthogonal Frequency Division Multiplexing.
+ Itiscurrently used as WiMax and WiFi.
SR
« SDRstands for Software Defined Radio.
« Itisthe form of open wireless architecture.
Advantages:
* Itprovides better spectral efficiency.
* Ithashigh speed, high capacity and low cost per bit.
Diradvantage:
' Eattery usageis more.
* Hard to implement.
=
SGa Hss [PORE
S1-MMF $11
se Gx
al Bo
Uu
Serving PDN
kK x2 $1-U gateway
(S-GW) Tsar Sa'eway
(P-GW) TSGi
: :
TE UE = IP Networks
IMS
eNodeB Internet
Apps

el Enhanced Packel Core (EPC)

EXUTRAN Fig. 3.11: 4G Architecture

{
ME Mobiity Management Entity: jon, Handover and Selection of Serving Gateway
| it
Used for Paging. Authentication.
:
g Gateway:
rwarding user data packe
Tis Used to Routing and Fo
 Wireless AnpilcationProtecy :4 ’ :
‘ie tenia aie

PDN-GW Packet Data Network Gateway:

It is used for User Equipment (UE) IP allocation.
HSS -Home Subscriber Server:
addressing
It is a user Database used for service subscriber, user identification and
PCRF -Policy and Charging Rule Function:
It provide quality of service and charging
eNode B-evolved Node B:
control.
It is used as radio resources management and radio bearer

3.5.5 Bays , |
LTE stands for Long Term Evolution and it was started as a project in 2004 by telecommunication
body known as the Third Generation Partnership Project (3GPP).
SAE (System Architecture Evolution) is the corresponding evolution of the GPRS/3G packet core
LTE and SAE.
network evolution. The term LTE is typically used to represent both
Long Term Evolution is the next step forward in cellular 3G services. LTE enhanced the Universal
Mobile Telecommunication Services (UMTS) in asset of points on account of the future generation
ents.
cellular technology needs and growing mobile communication services requirem
LTE evolved from an earlier 3GPP system known as the Universal Mobile Telecommunication System
(UMTS) which is turn evolved from the Global System of Mobile Communication.
(E-
e Even related specifications were formerly known as the evolved UMTS Terrestrial Radio Access
UTRA) and evolved UMTAS terrestrial radio access network (E-UTRAN). First version of LTE was
documented in Release 8 of the 3GPP specifications.
A rapid increase of mobile data usage and emergence of new applications such as MMOG
(Multimedia Online Gaming), mobile TV, Web 2.0, streaming contents have motivated the 3rd
Generation Partnership Project (3GPP) to work on LTE on the way towards 4th Generation mobile.
LTE offers a reduced latency delay, which is achieved with a simplified flat radio infrastructure in
which some of the functions have been moved from the Radio Network Controller (RNC) to the
evolved NodeB (eNB)
Another design goal is to increase spectrum efficiency and as such as a better cost per bit ratio and
better service provisioning.
Increased data rates will be realized the including the support of multi antenna techniques and in
combination with techniques such as Orthogonal Frequency Division Multiplexing (OFDM). — |
It will offer the flexibility in spectrum deployment and provide higher robustness against frequen
. .

selective fading for the system.

| :
The main goal of LTE is to provide a high data rate, low latency and packet optimized radio acter
a
technology supporting flexible bandwidth deployments,

Facts/Objective/Details of LTE
¢ The objectives of LTE are as follows:
1, LTE is the successor technology not only of UMTS but also of CDMA 2000
2. LTE is important because it will bring up to 50 times ,
‘ -_ PM _t__
performance improvement and much b 4
 aa
:
; vi de o
Sy to support high dat
ed ea ti n the ser vic es suc h as VoIP. Streaming
timedia, conferencing or even high spe cellular modem.
mie
LTE uses both Time Division Du l
:
is siplex (TDD) and Frequency Division Duplex (TDD) mode. In FDD
tr an sm
uplink and downli nk
h uplink and
jownlink use the same : Ssion used different in frti equen cy, whihilele ini TDD bot
carrier and same separated in time.
;
_ LTE supports flexible carrier bandwidths, from 1.4Mhz up to 20Mhz as well as both FDD and TDD.
i bandwidth from 1.4Mhz up to 20Mhz which bandwidth is
LTE designed with a scalab le carrier
ysed depends on the frequency ba of spe ctrum available with
a network
band and
cy the amo unt
operator.

. AILLTE devices have to (MI MO) Mul tip le Inp ut and Mul tip le Output transmissions, which
support rier simultaneously.
allow the base sta tio n to transmit; several data streams over the same car
the backhaul
network nodes in LTE are now IP base d, including
, All interfaces between
i ‘
tio ns. Thi : is great simplification compared to earlier
s
connection to th e radio bas e sta
t of them
wer e init iall y bas ed on E1/T 1, ATM and frame relays links, with mos
technologies that
being narrowed and expensive. s to ensure that the
mec han ism hav e bee n standardized on all interface
. Quality of Service(QoS) can still met when capacity
limits
sta nt del ay and ban dwi dth
for a con
requirement of voice calls
are reached. um and new spectrum.
GE /U MT S sys tem s exi sting 2G and 3G spectr
10. Works with GSM/ED .
ve r an d ro am in g to existing mobile networks
Supports hand-o

WA 4G-LTE Architecture low ing three main componen

ts:
is co mp ri se d of fol
architecture of LTE
e

The high-level network

t (UE).
1. The User Equipmen Ra di o Ac ce ss Network (E-UTRAN).
TS terrestrial
2.. The Evolved UM
Th e Ev ol ve d Pa ck et Core (EPC)- in the outside world such as
the
3, mmunica tes with packet dat a ne tw or ks
rfaces between the
The evolved packet
core co
or the IP multimedia subsystem. The inte
rporate. networks below:
internet, private co d Uu, si and SGias shown
system 9° e de no te
different parts of the

Servers
SGl PDNs
Wireless and Mobile Network 3.28
User ; a

a ewe orhitcture of the user equipment for LTE is identical to the one used by Ups and :
+s

cue
GSM which is actually a Mobile Equipment (ME).
The mobile equipment comprised of the following important modules:
1. Mobile Termination (MT) : This handles all the communication functions.
2. T : erminates the data streams.
9, vail terete hr (UICC) : This is also known as the SIM card for y.
equipments. It runs an application known as the Universal Subscriber Identity Module (UsMy,
E-UTRAN (The Access Network):
* The architecture of evolved UMTS Terrestrial Radio Access Network (E-UTRAN) has been illustrateg
below:
o The E-UTRAN handles the radio communications between the mobile and the evolved packet cote
and just has one component, the evolved base stations, called eNodeB or eNB. Each eNB is a base
station that controls the mobiles in one or more cells. The base station that is communicating
with a mobile is known as its serving eNB.

E-UTRAN

----- Signals Traffic

Fig. 3.13 : 4G LTE Architecture

o LTE Mobile communicates with just one base Statio
‘ : n a nd one cell at a time
following two main functions supported by and there af
eNB: .
1. The eBN sends and receives radio transmissions
te all the mobil es usin the analogue and
digital signal processing functions of the LTE air interface &

2. The eNB controls the low-level operation of al its mobiles, by sending them signals
messages such as handover commands, » DY sending

* Each eBN connects with the EPC by means of the s1 interface and it can als b
base stations by the X2 interface, which is mainly used for signall also be conne cted
‘i to neat”Y
oii
handover, ng and packet forwarding
e Ahome eNB belongs toa Closed Subscriber Group
(CsG a hb
USIM that also belongs to the closed subscriber ds ) and Can only be acce ssed by mobiles with Es
Oup, mn)
4
i
 ‘pi
sires ge
n
eee tege
tu
fic
Signals = ————— Traf
saosin ina
5 MME :
fret weg
1

'S10
}
a
>
1) S1-MME |
eo
"
1 7

'Sit
2 = wa
S1-U Servers
-GWa-———=
P.GW
=| SGI PDNs
S
s5/s8. ||

mee
The
ecture
Fig. 3.14: EPC Archit
shown in the above architecture:
,. Abrief description of each of the components carried forward from UMTS and GSM
The Home Subscriber Server (HSS) component has been subscribers.
mation about all the network operator's
0

and is a central database that contains infor outside world that is

Packe t Data Netw ork (PDN) Gatew ay (P-GW) communicates with the
The is identified by an
network
PDN, using SGi interface. Each packet data
packet data networks node (GGSN)
name (APN) . The PDN gatew ay has the same role as the GPRS support
access point
(SGSN) with UMTS and GSM.
and the serving GPRS support node on and the
(S-GW ) acts as a router , and forwards data between the base stati
The serving gateway
PDN gateway. e by
level operation of the mobil
Entity (MME) controls the high-
e The Mobility Management THe inteCince between the
Home Subscriber Server THES).
means of signalling messages and implementations,
and PDN gatew ays is know n as $5/S8. This has two slightly Different
serving networks.
are in the same netwo rk, and S8 if they = in different
namely S5 if the two devices of 100 Mbps in downlink and 50 Mbps
in Uplink
a peak data rate
LTE thus aims to provide
respectively.

s TCP/IP
Practice Question P? What are th e di sa dv an ta ge s of implementing
1 ar ee the the de si gn guidelines for WA .
What at ar
mobile i network? ? ? .
directly over the In wh ic h si tu at ion is WTP not used
otocol stac k.
Sesciie the waP pr mechanism?
which layer of WAP implements this
ve ribeibe didistillation t profile? what happens if a user agent profile is not used in WAP? How can
Desc
at is a user agen , ile be used oe?
a us er ag en t prof
distillation and da rd in
?
Internet stan
erent mobile
What are diff
uw

teway? s.
sociated protocol
. Explain WAP Ga e with diag ra m an d its as
res

chitectur
ano

Descri ng m od
elin detail.
programmi
APan
| ee

- Exe ain We
ple
Le

@ Describe the given application of wireless local loop.

@ Explain features of the given signal encoding technique for wireless network.
@ Compare PCM, DPCM, DM modulation techniques on the given criteria.
™@ Describe characteristics of the given spread spectrum modulation technique.
™@ State the procedure of scheduled maintenance of the given system.

To understand Basic Concepts WLL with its Architecture

|

To learn Signal Encoding Techniques

To study signal Spread Spectrum Modulation
To learn LEC Networks

Ps a Ly se re
e
s
4
than
system that uses wireless link rather
Bsences
is a gener ic term for an acces s
* Wireless Local Loop (WLL) telephone company’s switch.
cribers to the local
conventional copper wire to connect subs o. This type of system uses
* WLLis also known as Fixe d Wireless Access (FWA) or simply fixed radi
services to business and
og or digi tal radi o tec hno log y to provide telephone, facsimile, and data
anal
residential subscribers. terrain or
rapi d dep loy men t of basi c pho ne service in areas, where the
* WLL systems provide
pme nt mak es inst alla tion of trad itio nal wirelines service too expensive.
telecommunications develo Network (PSTN) for
can be eas ily inte grat ed in toa wireline Public Switched Telephone
* WLL system s
al wireline installations.
more quickly than the tradition ne code”, A line code is a chosen for use within a
© Electrical representation of bina ry codes is called “li
tio ns sys tem for tran s mitting a digital signal down a transmission line.
com mun ica
sig nal is use d to cre ate an “RF signal” that can be sent through free space. The line-coded
© Line coded
to bits on an optical disc.
signal can be converted

sa fn Stan ee cea ay eee Ce Riel e CRG Ane Nine ate tae

can be used to create a wireless

WLL stands for Wireless Local Loop. Microwave wireless links
loop as shown in Fig. 4.1.
[4.1]
 as
Wireless and Mobile Network : -
useher wavd}es
s thanio tra who
Operation: throd sitt es,at rat
mede
mmunicatio ns acc
e Wireless Loc al Loop (WLL) is a new co tomers and service P
wee n cus
transmission of information bet ss ). Access Network
Unit
coppe r or fiber optic. wirele
n (SF
fixed methods such as namely, itio
ne nts
* The architecture consists of three major compo ching Fur
Acces s Subsc riber Unit (wasv ) and $ wit
é (WANU), Wireless reless link that consis ts
or meat
): i (RPCU)
Wireless Access Network Unit (WANU rk and wi ns
underlying telephone netwo
¢ It is an interface between m
Ports (RP), Radio port Contre
Station Transceivers (BTS) or Radio
Register (HLR),
Manager (AM), Home Location
BS:
e Itisabase station of WLLsystem. i
tion transceivers and associated
;
switch
RPCU: Pe
Unit that connects & number of cell site basedwe and a telephone
* Radio Port Control een
vid es th e interface betw ng the air in
t
r implementi
antenn as. The RPC U pro
It pro vid es con tro l and sig nal ing functions fo
e
through the base stations. acy
r (AM ) le s au th en ti cation and priv
Access Manage hand
Man age r/H ome Loc ati on Register (AM/HLR)
* The Access ection.
ss Acc ess Sub scr ibe r Unit (WASU) @ tr ad it io na l telephone conn
2. Wir ele eless link into criber. This
loc ate d att he sub scr iber. It translates wir ano the r r in
1n terface to the subs
e itis network and
erface toward the authentication fu
nctions.
It provides an air int and tra nsc odi ng,
tocol conversion
interface includes pro ween
Fun cti on (SF) It is th e transmission link bet
3. Switching
All the SF inc ludes ISDN algorithms.
* Itcan bea digital switch. le.
WANU and SF can be microwave or cab

eee WLLM HNOLUG

4 major technologies. They are:
. The WLL system can be based on
4. Satellite-Based Systems: communities and isola ted islands.
® These systems provide telephony services for rural
h uae
K factor fo ri
Satellite systems are designed fora Gaussian or Rician channel wit
specifically for WLL ications 204
. These systems can be of two types Technology designed service rs
satellite systems as an adjunct
technology piggy backed onto mobile
but itt may oe
soa bet
grade of service comparable to wireline access,
a offers quality and
The former
#4
The latter promises to be less costly but,
due to bandwidth
telepho ne service (POTS) ons, may not offer the quality
comparable to plain old
grade of service
 Network

example of a satel}; 49
. sail (TES)technology saved echnolog—_ si
—

y ,
Sal Seting.
Raity de
tages: signed for WLL
is the HNS Tel
4. Low bit rate for voice
and data ephony1
2. Low cost mobile term
inals
4 It provid es quality and Rrade
of SETVice for
tages:
i. WILL @pplications
Thenumber of Satellite
s q
2. Handover Capability is on
an ia na EO Put restrictions on the syst
surface, 80 they need hang Over capah
-. I,
Satellites are em design
in motion rela :
2 Cellular-Based Systems, Pability for aij fixed and cellular . totive
the earth's
an
» These systems provide | pow
quality WLL services. » ¢, Cellular
a wiz ™,technolo
large gi
range, median subscriber density, and median
circuit
services. *S are primarily used to expand the basic telephony

limitation of such systems for WLL, user bandwidth represents a fundamental

advantages:
i They provide fixed wireless access and mobility.
2 They can be rapidly deployed in rural and urban areas.
3. They provide large power and operating range.
4. They provide medium circuit and medium subscriber
density.
Disadvantages:
i They are not recommended for deployment of indoors
and in picocells.
2 Airinterface is complex.
3. The user bandwidth is limited.
2. Fined Wireless Access Systems
_* These systems are proprietary radio systems designed specifically for fixed wireless applications,
| which may or may not be extensible to PCS or cordless.
"The Primary disadvantage of the cellular approach is its limitation on toll quality voice (new toll-
| Quality vocoders designed for cellular technologies may eliminate this problem), and signaling

The primary muadeanegs of low-tier PCS and microcellular approaches is their range. FWA systems
for zonal areas are designed to cover the local telephone area directly from the PSTN switches.
# The systems for rural areas provide connection at the remote ends
of rural links to the end users.

* Less expensive
: Itcan be easily installed
Yaag The installation time need is less.

. Limitation on toll-quality and signaling transparency.

 . secamenn iid WLL, Si cod
~~"
Wireless and Mobile Network i

4. Low-Tier PCS or Microcellular-Based Systems: ; d high circuit

A is a Wiz
high subscriber density, an ty
* These systems provide low power, small range, *Pand the
to facilitate rapid market en
services. These technologies are considered
capacity of the existing infrastructure. frequency bands. Com

* e service area
They are typically operated at 800 MHz, 1.5 GHz, 1.8 GHz, and 1.9 GHz eae ~~
with the cellular-based WLL, more base stations are required to —_ ms ceuve te fa la
2” existing in" Place to
* Operators may consider low-tier WLL technologies when
support backhaul. . existing low-tier PCS raqj
¢ For densely populated urban environments, WLL technologies based on °
technologies.
Advantages:
1. High Subscriber density.
2. Low power.
3. High circuit quality.
Disadvantages:
1. Transmission cost is more.

_ o
geri WLL Types (FWT and WT with Mobility)
WLL: FWT (Fixe d Wirel ess Tele phon e) and WT with Mobility as described in this
© There are two types of
section.
FWT (Fixed Wireless Telephone): e recuse concept
ems re simpl er form of cellu lar mobile systems. They utilize the fre
® WlLLsyst ers with a fixed
hand ing over conce pt. They are used to provide large number of subscrib
but without 60
withi n a short perio d of time. Omni directional or sectorial antennae, typically
telephone service use simple
ons whereas the subscribers stations can
degrees are installed at the central stati
directional antennae.
ng subscribers by radio with a nearby exchange (up
FWT systems are short distance systems connecti
nation point (typically 300m to 3Km away).
to 15Km away) or outside line plant access cable termi
nge to subscriber.
FWT systems are basically part of access network from excha
WT with Mobility:
ation is possible within the
These systems still provide a local terminal mobility since communic
ms are given below.
confines of the cell in which the subscriber is located. The major cordless syste
T-2)
4, British cordless Telephone System(C
2. Digital European Cordless Telecom System(DECT)
HS)
3. Japanese Personal Handy Phone System(P
4. North American Personal Access Communication System.
an Institute of
* Without going in to the details of the above systems, it may be noted that Indi
em in 1800 MHz band known as CORDECT.
Technology, Chennai has developed an indigenous syst
ent to localloop b etween
It has a range of about 3Km and has bright prospects for usage as replacem
To ° PoP 4 the
telephone exchange and subscriber. This system has already been su ly int rod uce d 10
ccessful
local network.
 wireless. and Mobile Network WLL, Signal Encoding...
4s

WLL Application
WLL applications includes;
4, Local phone service via wi relesslinecon
s nection
ed
than wir
2, Cheaper to install
3, Very prominent in non-industrialized nations,
Table 4.1: Radio Parameters of CT-2,DECT and PHS
Nall cece Wy fieabah __DECT ea re ead on PHS a
nies ~ : ANSTO
ETSI ETSI Lapanese__
Lene
___—_ Frequency MHz 864-868 4880-1900 1895-1918
| _Access Method FDMA MC TDMA MCTDMA__
1 12 4 ie
|___ Voice Chis per car
100 KHz 1.728MHz 300 KHz
|___RF chi spacing -
ADPCM ADPCM ADPCM
|_ Voice coding Algorithm
32 Kbps 32 Kbps 32 Kbps
as Voice coding rate
72 Kbps 1152 Kbps 384 Kbps
Channel bit rate
2 level FSK _ GFSK Pi/4QPSK__
| __ Modulation
sna

wae CON
ny in the U.S that provides
« LEC (Local Exchange
local service. grouped in to holding
the larg est LECs and the Bell operating companies which were
Some of when the Bell
coll ecti vely a s the Regi onal Bell Operating Companies (RBOCS)
companies known e are a
a 1983 cons ent decr ee. In addi tion to the Bell companies, ther
system was broken up by
as GTE.
number of independent LECs, such the local “central
also som eti mes refe rred to as “telcos” A “local exchange” is
« LEC Companies are .
of an LEC. Line s from hom es and businesses terminate at a local exchange
office” Transport Area (LATA) or
con nec t to oth er loca l exc hanges within a Loca ] Access and
Local exchanges T, MCI and Sprint.
Inte r Exc han ge Car rie rs (IXC s) such as long distance carriers. AT&
to

1QU
eed
ae. eee

0 f con ertin g binar y data (a sequence of bits) to a suitable format for

* Line coding is a proces s
errors.
l with minimum probability of
transmission through the channe
of line coding.
* Fig. 4.2 shows classification Line coding

t 4
Bipolar
| Polar
ve

foRZ
NRZ
o4
NRZ Manchester Differential
RZ
manchester AMI
Fig. 4.2 : Classification of Line coding
 Wireless and Mobile Network on WLL, Signal Encoding

type of in data is representeq

unipolar signaling, 4 High dura
tet e Ser igi nnn In this tion. A Low in data
by asalitioegdlona , Which has a duration Tp equal to the symbol
bit
t has no pulse.
inpu
h in data, though representeg
In this type of unip olar signaling, a Hig
by ons inerrant
orig the bit duration remains hip},
pulse od _ t he remaining half of the pit
but it immediately returns to cine SS eaof u
ows the absenc during
duration.
Bipolar Signaling: This is an encoding technique which has three voltage televels namely +, - and 9,
a a signal is called as duo-binary signal. An example of this type is Alterna Mark Inversion (Amp
or aA, the voltage level gets a transition from + to - or from ~ to +, having alteniate-26 60 be-of saa
polarity. A 0 will have a zero voltage level. Even in this method, we have two One
and Bipolar RZ. From the models so far discussed, we have learnt the difference RRP HE EE A
just goes in the same way here too.

Advantages and Disadvantages of Encoding Techniques

Advantages of Unipolar:
1. Simple mechanism to generate signal
Disadvantages of Unipolar: has a DC
average amplitude of unipolar encoded signal is not zero. It
1. DCcomponent:The and
associated with it. This component affects the between of the processing circuit
component
the media.
also the power required to transmit the signal through When signal
cause a problem while decoding.
2. Synchronization:A series of same kind of bits can
the beginning and ending of each bit. Whenever
is not varying, the receiver cannot determine on time. The
start of next bit, the receiver has to depend
there is no signal change to indicate the
and receiver clock distorts the signal. This
lack of synchronization between the transmitter
which carry clock pulse and allows receiver to
disadvantage is overcome by using parallel lines
s the cost and hence not used.
synchronize with transmitter. This increase
Advantages of NR-I: ted. As a
age levels are present. Since 1’s are represen
4. DC component is reduced because two volt
for consecutive 1's.
transition, synchronization is achieved
Disadvantages of NR-I:
0's is not achieved.
1. Synchronization for consecutive
Advantages of Biphase:
can be used for synchronization.
1. Atleast 1 transition in 2 bit period which
2. The waveform doesn’t have D
C component because every bit is encoded as +ve polarity for half
period.
bit period and -ve polarity for half bit
sition for each bit.
3. Error detection is easier because there is at least 1 tran
Disadvantages of Biphase: r bandwidth
transitions are taking place is high, and hence highe
4. The frequency at which
requirement.

ieee Properties of Line Codes or State Factors Deciding Selection of Line

Codes
deciding selection of line codes are explained in this section
¢ Properties of lin e codes or factors
a
21 De Component: signal must have 2eT
com mun ica tio n cha nne ls do not all ow transmission of de signal. Line code
e All component.
zero dc
average value i.e.
_ OO Ne Sy

Mobile Network
988 and
47 Signal Enco
ding.--
we! WLL,

lity;
self Clocking Capabi
prrespective of information bit sequence line co de used should take at least one transition during
gac erval.
h bit int fo
qhese transitions are used by receivers
ervor Detection: ¥ synchronizations with transmitter.

i of li .
. tify the errors in the received si signal
helps to iden
‘
ek j oat f line code
Multilevel binary group codes provides self error detectio n capability. :
pandwidth Compression:
Line come ue should = the minimum necessary bandwidth for transmission.
The multileve codes requires less bandwidth as compared to other cod
uN:
pifferential Encoding:
gen era ted usin g diff eren tial enco ding is usef ul for thos e communication system where
Line cote
rsion
transmitted waveform sometimes experiences an inve
ror example, differential machester.
Transperancy:
’s and zero’s.
it should be possible to correctly tetrive data regardless of the pattern of one
phase encoded having good transparency.
;
Noise Immunity: ty.
used should have very high noise immuni
Ability to reject noise called noise immunity. Line co des e they will have high
The NRZ format have better noise immu nity than t hat of other codes becaus
average power.
Minimum Crosstalk: er to minimize
uld be suc h tha t at low freq uenc ies it should have low average pow
Line codes sho
crosstalk between adjacent channels.
crosstalk.
RZ group signal provides minimum
ar NRZ Encoding Scheme
Comparison of Unipolar RZ and Unipol
Table ae —*
ate
ented by an
aah RZ

In this format each “O” is repres

Pie RCE
ented by an
In this format each “O” is repres pulse With
pulse With off pulse(0)and each “1” by anon
off pulse(0)and each “1” by anon
amplitude A and duration Ty.
amplitude A and jduration T,/2. does not
return to zero During the on time, the pulse
During the on time, the pulse return to zero after half bit period.
| after half bit period. .
Unipolar NRZ pulses carry more energy
| Unipolar RZ pulses carry less energy:
"© ~~ ———— Clock recovery is Good.
[Clock recovery isPoor,
Synchronization is not essential.
ial.
Synchronization is not essent

Codes
O4 y Guidelines to Draw Line
Guide;
Uidelines to draw line codes waveforms are as follows:-
l
NRZ- L: One is rep res ent ed by one level, zero is represented by other leve
1.

—_
Wireless and Mobile Network WLL, Signalg 3
4.8
2. NRZ-M: One is represented by change in polarity and zero is represented by no change ‘

polarity.
3. NR2-S: One is represented by no change in polarity and zero is — by ee in Polarity
y zero level, :
4. Unipolar NRz: One is represented by high level and zero is represented
5. Unipolar RZ:One is represented by half bit width pulse and zero is represented by y, Pulse
condition.
6. Polar RZ (Bipolar RZ): One and zero are represented by opposite level polar pulses that are One
half bit in width.
7. i and ze, is
RZ AMI: One is represented by show half wave ,for alternate one change polarity
representedby zero level.
8. Bi-g-L ae Level or Split Phase Manchester): One is represented by 10 and zero is

represented by 01.
9. Bi--M (Biphase Mark):
* A transitions occurs at beginning of every bit p eriod. ;
¢ One is represented by second transition one half bit period later.
* Zero is represented by No second transition.
10. Bi--S (Biphase Space):
e Atransition occurs at the beginning of every bit per: iod.
© Oneis represented by no second transition.
later.
* Zero is represented by second transition one half bit period
11. Dicode NRZ:
is sent.
© AOne to zero or zero to one change polarity. Otherwise zero
12. Dicode RZ:
* AOne to zero or zero to one transition produces a half duration polarity change.
¢ Otherwise zero is sent.
13. Delay Mode: .
One is represented by transition at the midpoint of the bit interval.
Zero is represented by no transition unless it is followed by another zero.
In this case a transition is placed at the end of bit period of the first zero.
14. Polar Quaternary:
« Two bits are grouped together.

00 -3A/2
01 -A/2
10 A/?

a 3A/2
15. Gray coded: Two bits are grouped together

00
04 -A/2
11 A/2
10 3A/2
 se
Va erential Manchester:
bj
46° qransition at middle of every
t interya}
trans
zero is represented using
ition at
ora RZ, NRZ Manchester an ap
o NRZZ
Manchester Rinni
>
|
S

ao
=

.
é
:

.
mannchester
Differential

t—

- ODULATION
woltude Shift Keying (ASK) is the digital modulation technique in which the amplitude of the
usoidal carrier will take one of the two predetermined values in response to 0 or 1 value of the
sie Mput modulating message signal.
ade shift keying is the simplest form of digital modulation. | Here the: carrier is a sine wave of
hea.
Wency,

; digital signal from the information source is a unipolar NRZ signal which acts as the modulating
- The ASK modulator is nothing but a multiplier followed by a band pass filter as shown in

| bie "8.4.4 (a).

he ° “Aultiplication, the ASK output will be present only when a binary ,1 is to be transmitted ang
© digital input is ,0 then we get zero output as shown in the waveform above Fig. 4.4 (b).
 WLL, Signal E
Wireless and Mobile Network 4.10 a
Digital data signal 4 o o 1 0
Digital signal ; ;
Unipolar NRZ

Carrier signal

penend Inneslimited Vas (t) z = 4 sin (2, fotct)

(a)
_ (b)
Fig. 4.4: ASK
binary ,1 is to be sent the carrier is
¢ From the waveform analysis we can conclude that when a
itted.
transmitted and when binary ,,0 is to be sent then the carrier is not transm

BPSK Generator With Block Diagram and Waveforms

ation from the source may be a
¢ BPSK stands for Binary phase shift keying. The digital inform
unipolar NRZ data which varies between values 1 and 0.
But if digital data is unipolar then during 0 data output will be zero due to use of multipliers at
whose
transmitter. So to avoid this problem the unipolar data is first converted into bipolar data
value varies between + 1 and -1.
¢ The transmitter of BPSK signal is shown in the above Fig. 4.5.
, Digital input

Carrier

BPSK

Fig. 4.5: BPSK

* The digital signal from the information source is a unipo i ich i
bipolar signal. This signal acts as the modulating a
she cn in
PSK mod e is nothing but
ulator
multiplier followed by a band pass filter as shown in above Fig. 4.5; a
* Due to multiplication, the BPSK output will be present
with 0° Phase shift when a binary
transmitted and when the digital input is ‘0’ then we get BPSk ‘1’ is to be
in the waveform Fig. 4.6. cutput with 180° phase shift as shown
* From the waveform analysis we can conclude that
when a binary ‘1’
transmitted with 0° phase shift and when binary ‘0’ j s to be sent thes is to be se nt the carrier
ier isi
180° phase shift. € carrier is transmitted with
* The transmitted BPSK signal is s(t) = b(t) /2Ps cos Got.
y" =e
wreioes and Mobite Network
4.11 Ww

qghe phase of this signal ch iver. This

fn sa ® depe ndin g on the time delay from transmitter t rece
phase change is generally ed in the transmitted signal, Let the phase shift be 9.
qnerefore the signal at the input f + 8.
Pi'receiver is s(t) = b(t) 2Ps cos wot
waveforms:

OV ee

'
' I Time
' Inqut binary eq uence
' ' 1
'
'
'
1

'
'
I Time
'

BPSK modulated output wave

Fig. 4.6: BPSK Waveforms

Block Diagram of PCM Transmitter and Receiver

. PCM stands for Pulse code Modulation. X'g(kT.)
= Instance
k isamele
Analog speech x(t) x(kT,)

Rb
o t hits/sec
— Error Noise due
x(t)
to quantization
7 Se

x',(KT,)

m of a PCM coder - decoder

Fig. 4.7: Schematic diagra
below:
ch ni qu e in det ail wit h block diagram as described
* The te
d by the low pass filter.
* The signal is band limite The pr ocess of analog to digital conver
sion primarily
the fil ter ed sig nal to be cod ed.
* Let X(t) denote
involves three operations:
1, Sampling of X(t),
X (kT;) and
ion (i.e. app rox ima tio n) of the discrete time samples,
2. Quantizat
3. Suitable encoding of the quantized time samples Xq(kT,).
R, =1/T, is the sampling rate (samples /sec).
* Tsindicates the sampling interval where
per second (T, =
ta nd ar d sa mp li ng rat e for speech sign al, band limited to 3.4 kHz, is 8 Kilo-samples
* As theorem.
t’s sampling
125p sec), thus, obeying Nyquis
 4.12 WL, Signet e
Wireless and Mobile Network

Encoding: ropriate signal calleq

Encoding is used to translate the Discrete se t of sample va
lues to more app
« resent 2”. After coding binary
we may rep
Code. Suppose in binary code word ‘n’ bits are used, then
or pipolar.
signal is represented by train of pulses as NRZ, RZ un ipolar
Code Quantization x(t) (v)
number level 4
7 3.5

6 25
2
5 1.6
1
4 0.5
0
3 -0.5
=1
2 -1.5
-2
1 -2.5
-3 1
0 -3.5 -4
1
! 2 4 a 4
I t
ot “25 -3.5
Natural sample value 1.3 3.6 2.3 0.7
0.5 -0.5 7 0
3.5 2.5
Quaentized sample value 1.5 7 6 4 001 000
Code number 5 414 110 400 011
PCM sequence 101
n : for the
les, and pulse codemodulatio modulation
Fig. 4.8: Natural samples, quantized samp signal processing and
ken for furt her digi tal
* The PCMcoded bit stream may be ta
purpose of transmission. par all el bi t- st re am at its input so that it can
expects a se rial or sample
* The PCM decoder at the receiver the enco ding ope rat ion ) to generate quantized
of bits (as per
decode the respective groups
on filter
sequence [x', (kTs)].
ore m for ban d lim ite d sig nal s, the low pass reconstructi
Following Nyquist’s samp lin
g the
ginal speech si gnal x (t).
a close replica x"(t ) of the ori
e
uces
whose f, = message BW is prod 0
: I
0 0 1 0 1
110 4 1 1
|
T ;*—Bit time slot

Codeword time slot

(a)
I I I
1 I I
I I t
1 ' I
1 ! 1
I 1 '

o tT a oF 47 ST GT 7T BT ST 40T = 12T
Fig. 4.9:
4.9 : (a) PCM seq uence. @):(b) Pulse PCM
(c) Pulse waveform(transition bisteraait ele
s
 a and Mobile Network

4.19 bs
wultiplexing WL, Signal Encoet
pifferent message sources a re Tj
synchronized. tire = Multiplexed for this receiver and transmitter are
channel Noise and Error Probability
the Performance of pcm system
isin
1, Channel Noise : Introduceg i nt fluenced by two major sources of Noice.
ansmission path
2, Quantizing Noise : Introduc
ed in transmitter
4, Channel Noise
pue to Channel Noise Symbol ‘0’ a
PPears as ‘4’ and Vic
probability of error e versa.

P, = 1 /2*
where No is noise power, erfc (1/2*(Emax /No)””)
quantizing Noise
Is produced at transmitter of PCM
b Y founding off analog sample value to nearby permissible level.
quantizing Noise

v9 = A/12
where A is step size
Characteristics of PCM
1, Average Probability of error depends on ratio of Peak Signal energy to Noise spectral energy.
2, In PCM signal is regenerated so effects of amplitude , phase and nonlinear effects in one link has
no effect on next link.
3. Transmission requirement PCM link are independent of total length of system.
4. PCM is very rugged system , means less noise effect unless noise amplitude is greater than half of
pulse height.
Advantages
1, In PCM signal is regenerated so effects of amplitude, phase and nonlinear effects in one link has
no effect on next link.
2. Transmission requirement PCM link are independent of total length of system.
Disadvantages:
1, High bit rate and noise limits the use.
Model Waveforms:

Fig. 4.10 : Waveforms of (a) Modulating Signal (b) Sampling Signal (c) PCM output

Cy orcm Transmitter and Receiver

DPCM stands for Differential Pulse Code Modulation. The technique with block diagram is shor in
Fig. 4.14.

—
 “a

Wireless and Mobille Network 4.14

: WLL, Signal Encodip,

* ; l are usually correlated as amplitude 0 f signal does not change much ; e

In PCM Samples of signa
ct of speech signal is exploiteg in
ormation. This aspé
ieee a carries redundant inf
: have been strategically added to is
* that a predictor bl TT ioeen and a sub tra cti on uni t
chain of ock, a summing unit x (kTs) directly to a linear
PCM cod er ins tea d of feeding the sampler output
of blo cksof
quantizer. An error sample ep (kTs) is fed.
v(nTs)
x(NT,) a(nTs)

Predicti
current sample | To be transmited
Prediction error

(<— Past samples (already sent) ——>

Only prediction error is sent

modulator
Fig. 4.11: Schematic diagram of a DPCM
:
e Theerrorsample is given by the following expression
@,(nT;) = x (nT,)- x* (nTs)
that ep (nTs) is very
and is supposed to be close to x (nT,) such
x (nT,) is a predicted value for x (nT,)
‘prediction error for the n™ sample’.
small in magnitude e, (nTs) is called as the valent PCM
visa ge smal ler step size for the linea r quantizer compared to the step size of an equi
e Ween bits at
achieve higher SQNR for DPCM codec delivering
quantizer. As a result, it should be possible to
c.
the same rate as that of a PCM code
d bit rate compared to a PCM system if an SQNR as
There is another possibility of decreasing the code
lizer is sufficient.
achievable by a PCM codec with linear equa
n in Fig. 4.12. The scheme is
A block schematic diagram of a DPCM demodulator is show
r unit identical to the one used in the
straightforward and it tries to estimate u(kT,) using a predicto
modulator.
in a small quantization error of
We have already observed that u(kT,) is very close to x(kT,) with appropriate low pass
by passing the u4(kI,)through an
q(kT.). The analog speech signal is obtained
filter.
Demodulator
V(nT;) A output
MNT, X(t) Output
Analog output

SG U(nT 3)
;
Fig. 4.12 : Schematic diagram of a DPCM demodulat
Or
a

reless and Mobile Network WLL, Signal Encoding:--

E mel
advantages
4, Less bit rate generated so better
utilizatio y+); ‘
er
_ 2, Redundant information is less carrie n of bandwidth.
;

pisadvantages
4, Predicator increase hardware co mplexit:
plexity of system,
model Waveforms:

1
|

Output of (a) D/A Converter (b) Demodulated

Fig. 4.13: Waveforms

Block Diagram of Delta Modulation

ow and shown in Fig. 4,14.
ds for Delt a Mod ula tio n. The technique in detail as described bel
* DMs tan ted signal
M is reduced considerably, i.e. if we sample a band limi
* Ifthe sampling interval ‘Ts’ in DPC have higher
er tha n the Nyq uis t sam pli ng rate, the adjacent samples should
at a rate much fast
correlation. So, one may even think of
am pli tud e difference will usu ally be very small.
* The sample-to-sample dulation (DM) is based on
of the di ffe ren ce signal. The p rinciple of Delta Mo
only 1-bit quantization — |
this premise. ivalent to a two-
tio n is also vie wed as a 1-bi t DPC M scheme. The 1-bit quantizer is equ
* Delta modula angement for
ato r (als o cal led as a har d limi ter) . Fig. 4.14 shows the schematic arr
level compar
lated signal. :
generating a delta-modu = V(kT,) Modulator
x(kT.) +f. > e(kT,)
2 (kT)
Over output
samp! >
input =
we ewe -
=- = =-|—- --= I
I
1
! Accumulation
I
! unit
I
|
' X(KT.) I
|
I
I
i
 I a a a I I CE aa ay

4.16 WLL, Signal Encoding...

Wireless and Mobile Network
x(t)
Granular noise

Slope overload
distortion

ulator
Fig. 4.14 :Block diagram ofa delta mod
Note that, e(kTs) = x(kTs) -x”(kTs)
= x(kTs) -u([k -1]Ts)
Features of Delta Modulation eliminated and
dic tio n unit - the pre dic tio n unit 0 f a DPCM coder (Fig. 4.14) is
e No effective pre
replaced by a single-unit delay element. t
levels is used. The quantizer output s imp
ly indicates whether the presen
* A1-bit quantizer with two
its accumulated approximation x*( kTs)
input sample x(KTs) is more or less compared to
ll steps.
® Output x‘(kTs) of the delay unit changes in sma ed version
zer outpu t with the previous accumulat
e The accumulator unit goes on adding the quanti
xA(kTs) . u(kTs), is an approximate version of x(kTs).
is dependent on the sampling rate.
e Performance of the Delta Modulation scheme y close
e when two consecutive input samples are ver
© Most of the above comments are acceptabl only
to each other.
e(KT,) = x(KT)—{x({k- 1]T.) + v([k- 1]TS)}
further, v(kT,) = €q(kT,) = s.sign[e(kT;)]
Here, ‘s’ is half of the step-size 6 as indicated in Fig below
+8

6=2s

q
-S

Fig. 4.15

¢ This diagram indicates the output levels of 1-bit quantizer. - No Note that of 8 is the step size,
‘ the two
output levels are+s
nditi iti
® assuming
Now, w, assuming 2 zero initial condition of the accumulator, it is easy to see that

wk) = s+E sign [eGT)]

 She = —-
i
p

and Mobile Network WLL. si nal Encodin) ro

winglos® 4.17

k
u(kT,) = z Vv (jT,)
1

ryrther, x(k.) = u((k-a)r, » Evgry

jnt
Ab ove eq. shows that is essenti
entially an accumulated version of the quantizer output for the a
signal e*(kt,)- x“ (kts) . also gives a clue to the d emodulator struct M,
‘ 4.16 shows @ scheme for demodulation.
Fig. eae ee®
V(KT,) 4400

X(KT,)

Fig. 4.16 : Demodulator structure for DM

the demodulator normally starts wit h no
The input to the demodulatoris a binary sequence and
prior information about the incoming sequence.
lesson that, u(kTs) closely
Now, let us recollect from our discussion on DPCM in the p revious
represents the input signal with small quantization error q(kTs), i.e.
u(kT.) = x(kT;) + e(kT;) in the Delta
umulation unit
Next, from the close loop including the delay -element in the acc
modulator structure, we can write
u([k-1]T,) = x(KT,) = x(keT,) - e(kT,) = x((k-2]T,) + a(Ck- 275)
Hence, we may express the error signal as,
u(kT.) = {x(kT,) -x({k-4]T,)} ~ a([k-1]Ts) the
error signal is the differenc e of two consecuti ve samp les at the input except
That is, the
is small).
quantization error (when quantization error
Advantages of a Delta Modulator over DPCM word-
le of x(kTs ) is repr esen ted by only one bit after delta modulation, no elaborate
1. As one samp ces hardware
the input of the demodulator. This redu
level synchronization is necessary at
M demodulator.
complexity compared to a PCM or DPC tally.
essary if the demodulator in implemented digi
2. Bit-timing synchronization is, however, nec
r is less compared to DPCM as the predictor
3. Overall complexity of a delta modulator-demodulato
unit is absent in DM.
limitations of DM: by step
signal amplitude changes fast, the step
1, Slope Over Load Distortion: If the input
Wireless and Mobile Network i
4.18 -
that approach has another
An intuitive remedy for this problem is to increase the step-size 5 but
serious problem given below.
2. Granular Noise:
step-siz e is made arbitrar ily large to avoid slope-overload distortion, it may lead to ‘granular
If the over limited time
noise’. Imagine that the input speech signal is fluctuating but very close to zero
During such moments, our delta
duration. This may happen due to pauses between sentences OF else.
of 4101010...., reflecting ea the accumulator
modulator is likely to produce a fairly long sequence at the
input signal.This phenomenon is aaeterd
output is close but alternating around the
This is known as
demodu lator as a small but perceptible noisy background.
output of the delta to Adaptive Delta
g the step-size, leading
t approach of adaptin
‘granular noise’. A more efficien a
overload: oe
Modulation (ADM), Condition for avoiding slope within a
changes more than half of the step = (i.e. by i“)
input signal
We may observe that if an on on the
be slope-o verload i
distorti i
on. So, the desirired limiting conditi
sampling interval , there will
input signal x(t) for avoiding slope-overloading is,
dx(t)
dt }max
Ss
s Ts

3. Model Waveforms:

output Waveforms
t and message signal (c) D/A converter
(a) Clock input (b) Delta modulation outpu
Fig. 4.18 ; Waveforms

Delta Modulation
Slope Overload and Granular Noise with Respect to
f |

|
Slope
overload
| Granular NOISE

x(t) 8 (Step size)

|
x(t)
Time
noise
Fig. 4.19 : Graph showing Slope overload and Granular
drawbacks as under:
The delta modulation has two major
 wie less and Mobile Network 4.19 wht, Signal Encoding

glope Overload Distortion

4.
js distortion is arises be
As can be observed from
ee dynamic range of the input signal.
anit the rate of rise of .
ignal x(t) is so high that the staircase signal cannot approximate
esteep size ,A* becom Se
case signa l x’(t}t o follo w the step ment of x(t).

sas there ta alange arth Small for stair

staircase approximated signal and the
orl iginal input signal
the
wn asn slope overload distortion. To reduce this error, the step size must
x (t). This error or noise isInewan
pe increased when slope of signal x (t) is high
S occur along
‘nce the step Pp size of delta modulator remains fixed, its maximum or minimum slope
ginc
straight lines. Therefore, this modulator is also known as Linear Delta Modulator (LD™).
granular or Idle Noise:
ations in the
Granular or ss noise occurs when the step size is too large compared to small vari signal is
staircase
input signal. This means that for very small variations in the input signal, the
by large amou nt (A) becau se of large step size figure shows that when the input sign al is
changed
almost flat, the staircase signal x‘(t) keeps on oscillating by +A around the sig nal. this
The solution to
The error between the input and approximated signal is called granular nol se,
problem is to make step size small. (to
step size is required to accommo date wide dynamic r: an ge of the input signal
Therefore , a large
noise. In fact,
slope overload distortio n) and small steps are required to redu ce granular
reduce

od
daptive delta modulation is the modification to overcome these errors.
Comparison in PCM, DPCM a nd DM

Each discretesampleis | Difference between sampling rate > Nyquist

Principle sampling rate so ample-
quantized, encoded and consecutive samples is
e amplitude
sent. quantized, encoded and | to-sampl
sent. difference is very low
.
about 1-bit quantization
which is encoded and
send
redundant
Carries redundant Carries Less redundant | Carries high
Redundant information than PCM.
information. information.
Information Higher than PCM
Higher compare to Very Low compare to
Bit rate generated
PCM
DPCM
to PCM Less compare to DPCM,
No. of Quantization High compare to DPCM, | Less compare
PCM
levels, DM
to PCM, High compared to PCM ,
Quantization Noise High compare to DPCM | Less compare
DM DPCM due to step size
called as Slope overload
error and Granular
Noise
Pa
Yes No, instead single Delay
poe No
element is used.
Tement Contd. ...
 ~~
4,20 Wh, Signal Encoding...
Wirel ess and Mobile Network ——$<$ $$
Less bit rate generated Due to one bit
Advantages In PCM signal is
| so better utilization of quantization, no
regenerated soeffects
elaborate word-level
of amplitude, phase and | bandwidth. synchronization is
nonlinear effects in one necessary at the input
link has no effect on of the demodulator.
next link. This reduces hardware
complexity compared to
a PCM or DPCM
ae demodulator.

Redundant information Overall complexity of a

Transmission delta modulator-
ied
requirement PCM link _| is less carr demodulator is less
are independent of total compared to DPCM as
length of system. the predictor unit is
absent in DM.
Predicator increase Higher Quantization
High bit rate and noise
Disadvantages
hardware complexity of noise compared to PCM,
limits use DPCM
system.
Video streaming
Video Chatting
Application Telephone Speech

spr ead Sp ec tr um Sig nal Different from N' ormal Signal

BR EA l signal. The spread spectrum sign
al
ban dwi dth tha n that of no rma
* This signal occupies a larger
ing.
invariably uses some kind of cod is obtained with the help
spr ead ing at the tra nsm itt er an d dispreading at the receiver
The spectrum nt of the information
d ass ociated with an ss signal is independe
of this code word. The code wor
carried by the signal. .This makes it appear like
ss signal is pseu dorandom in nature
The most important point is that cially designed
random noise. Hence the normal rece iver cannot demodulate ss signal. Only a spe
the information
rece iver can demodulate it to recover
Advantages of Spread Spectrum:
4. Low power density
2. Redundancy
3. Anti-jamming
4, Anti-interference
5, Low probability of intercept
6. Message privacy
and timing
7, High resolution raging
ad Spectrum :
Disadvantages of spre
h is rewired
4, Largeamount of bandwidt
Spectrum:
Applications of Spread
istance to gaining
4. Military application-res
ication
9. Secure commun
 ee
=

Wireless and Mobile Network

Encoding...
wLL, signal

ae na
in satellite communica
tion
SNXNawnan

olice radar cane mploy spread spe

ctrum to avoid detection by detectors employed by drives
Low densi ity power spectra for signal
hiding

GPS
Multi ' :
ultipath rejection in ground based mobile station.

Direct Sequence Spread Spectrum (DSSS)

° ‘ghee ace Spread Spectrum (DSSS): In direct sequence, the serial binary data is mixed with a
ph ase-
cy pseudorandom binary code at a faster rate and the result is used to
modulate . carrier. Direct Sequence Spread Spectrum Coherent PSK Transmitter
e The arenas system reduces the interference by averaging at over a long period the DS Ss system is
a averaging system. This technique can be used in practice for transmission of signal over 4 band
Binary Phase Shift (BPSK) is
pass channel (e.g. satellite channel). For such application the coherent
used in the transmitter and receiver,
Transmitter: Fig. 4.20 shows DSSS transmitter.
}
4 1 1 \ 7 transmitting
: antenna
0 0 0 RF power
i — — amplifier
i.

Clock a

Fig. 4.20: DSSS Transmitter

Explanation:
ry dat a is applied to an X-
bloc k dia gra m of DSSS tran smit ter is shown in Fig. 4.20. The serial bina
e The
c ode that occurs faster than binary data.
random
| OR gate along witha serial pseudo
ator. The carrier
al deve lope d at the outp ut of the X- OR gate is then applied to a BPSK modul
© The sign
X-OR output.
d 180° by the 1s and O“s of
phase is switched between 0°an es the
tin g carr ier, bein g muc h high er in frequency than the data signal caus
The signal phase modula complete
tiple wide ly spaced sidebands whose strength is such that the
modulator to produce mul
at dea l o f the spec trum . Thus the signal is spread. Also because of its
signal takes up 2 gre
than wideband noise to a
om ne ss , the res ult ing signa 1 is appears to be nothing more
rand
ban d receiver.
conventional narrow
pse udorandom code is called a chip and the rate of the
code is called the
© One bit time for the
an the data rate.
chippin g rate is faster th
chipping rate. The are applied to
si gn al X(t ) and the locally generated replica of the PN sequence generator
* The receiver tion
er thi s is 3 tage of multiplication. The multiplier performs the de-spreading opera
a multipli local carrier applied to it.
of mu lt ip li er is th en applied to a coherent BPSK detector with
output
 _

Wireless and Mobile Network 4,22 et Sian Encoing

data signal.
¢ At the output of coherent BPSK detector we get back the original signal d(t)
Receiver:
| Coherent os| ¥(!) output
ignal
fe BPSK
detector — =

|
The DS-BPSK recelver
(OR)
ifv> Osay'1’
if v <0 say ‘0’

Pseudo-nols
Thershold = 0
oer
Fig. 4.21: DSSS Receiver
:
Features of DSSS: ation
1. Itprovides good security against pote
ntial jamming or interpret
nst narrowband jamming signal
2. The DSSS is extremely effective agai DSSS signal
tion signal can coexist with
3. The narrowband communica erference.
effective against broadband int
4. The DSSS signal is not very
Disadvantages of DSSS: S system slow
ch syst em, the acqu isit ion time is too large. This makes DSS
4. With the serial sear The length of such
rate d at the PN code gene rator output must have high rate,
2. The sequence gene
ugh to make the sequence truly random
sequence needs t o be long eno dth is less than that of FHSS
ed is very large, But thi s bandwi
The channel bandwidth requir
system
distance between the transmitter and receiver
4. The synchronization is affected by the variable
Applications of DSSS System:
4. Tocompact intentional interference
To reject unintentional interference
tipath propogation
To minimize self interference due to mul
pwn

signal
In the low probability of intercept
y
In obtaining message privac
DSSS
code division multiple access with
AY

FWY rrequency Hopping Spread Spectrum (DSSS)

e FHSSstands for Frequency hoping spread spectrum modulation
and fast frequency hoping)
Different Types Of Frequency Hoping (Slow F cy of
is the ieee: of Modifving
e FHSS combines spread spectrum modulation with MFSK. It ifying Frequen
MFSK Signal using frequency hope generated by bits of PN sequence
 Sk
,
nd Mobile Network r indee
: 4.23
. WLL, signal Encod
yo
Sursx(t)

(b) FHSS/M-ary FSK Receiver

Fig. 4.22: FHSS Transmitter and Receiver
M-ary FSK.
tal data modul ates a carrie r using a traditional modulation scheme like
+ Thebinary digi but
signal is then modul ated a secon d time by another carrier frequency,
+ This M-ary FSK modulated ar intervals of T., the chip period,
or rather hops, at regul
this carrier frequency changes its value, accordingly to a pre-determined,
from one value to another form among 4 given set of values,
by a pseudo-
rn. This carrie r frequ ency hoppi ng is controlled at the transmitter
pseudo-random patte
in Fig. 4.23.
random code generator, as shown in modulated by a
ary dat a is firs t use d to pro duc e an M-ary FSK modulated signal. This is aga
* The bin generator.
sizer that is controlled by a PN code
carrier produced by a frequency synthe FH Spreader
;
Spread
spectrum signal

(a) Transmitter
 4,24 WLL, Signal Encodin
Wireless and Mobile Network
FH Spreader
Spread Binary data
spectrum signal

(b) Receiver
2%
Fig. 4.23 transmission, binary
.For
uency-hopping system
e Fig. 4.23 shows a typical block diagr am for a freq such as Frequency
digital-to-analo g encoding scheme,
data are fed into a modulator using some
(BPSK).
Shift Keying (FSK) or Binary Phase Shift Keying or pseudorandom
on some base freq uenc y. A Pseu d o Noise (PN),
¢ The resulting signal s,(t) is centered this is the spreading code
referred to
into a table of freq uenc ies;
number, source serves as an index
previously. At each successive interval
2* carrier freque ncies.
* Each k bits of the PN source specifies one of the
selected.
(each k PN bits), a new carrier frequency is quency hops among a set
zer gene rate s a cons tant -frequency tone whose fre
¢ The frequency synthesi m t he PN sequence. This is
ping pattern determined by k bits fro
of 2" frequencies, with the hop
ng signal c(t).
known as the spreading or chippi signal
the sign al pro duc ed from the initial modulator to produce a new
¢ This is then modulated by
on the selected carrier frequency.
with the same shape but now centered quency, yielding the
filte r is used to bloc k the diff eren ce frequency and pass the sum fre
e Abandpass
final FHSS signal s(t). of PN-derived
the spr ead spe ctr um sign al i 5 demodulated using the same sequence
On reception,
ed to produce the output data.
frequencies and the n demodulat
of the form s (t) defined on the pre
vious slide, will be received. This is
At the receiver, a signal
multiplied by a replica of the spreading sign al to yield a product signal.
ck the sum frequency and pass the difference frequency, which is
A bandpass filter is used to blo
the binary data.
then demodulated to recover
:
Advantages of FHSS System
S needs shorter time for acquisition.
4. Theserial search system with FHS
dependent on the distance.
2. The synchronization is not greatly
of DSSS system.
3, The processing gain is higher than that
tem:
Disadvantages of FHSS Sys to be used.
quency synthesizers are required
4. Complex and costly digital fre
is too large (GHZ).
2. Bandwidth of FHSS system
FHSS:
Applications of
k LAN) standard for wi-fi,
4. Wireless local area networ (W
ard of Bluetooth
2. Wireless personal area network (WPAN) stand
 ots 0 Moblle Network
4,25 w
comparison of FHSS and Dsgg System:

RE ae Pra cae _Table 4,4

tion: PN sequ i eee FHSS __ nen

in different
mene of large bandwi dth is Definition: Data bits are rransmitted
change d >Y
Oegid
mu with and information signal frequency slots which are
— — ec
sequence
a chip rate = max(Rh, Rs) et ag |
application Se multipath delays: DS | FH system can ae the same mitigation only .
and if
a aie ‘ mitigation method as such | the hopping rate is faster than symbol rate
signal render ali m tipath signal copies that are | the hopping bandwidth is larger
delayed by more than one chip time from direct
,ignal as invisible to the receiver eine
For commercial applications implementation of | Implementation of FHSS radio can be costly and
need of high speed frequency
psss ms with large gap can also be costly due | complex due to
| toneed of so speed circuits synthesizers ener
psss radios encounter more randomly | FHSS suffers from burst error
distributed error that are continuous and lower
level
| Modulation Technique : BPSK Modulation Technique : M-ary FSK

Long acquisition Time Short acquisition time

psss is distance dependent In FHSS , ffect of distance is less
processing gain is less Processing gain is higher
| Bandwidth required is less than FHSS system Bandwidth of FHSS system is too high

Effect of fading is more Effect of fading is less

y ency Hopping:
Comparison of Slow Frequenc and Fast Frequ
Table 4.5 a
oe 2 Eee

More than one frequency hops are required to

More than one symbols are transmitted per
frequency hop. transmit one symbol.
Chip rate is equal to hop rate.
Chip rate is equal to symbol rate.
Hop rate is higher than symbol rate.
Symbol rate is higher than hop rate.
one or One symbol is transmitted over multiple carrier
Same carrier frequency is used to transmit
in different hops.
Tore symbols.
carrier A jammer can not detect this signal because one
A jammer can detect this signal if the
symbol is transmitted using more than one
frequency in one hop is known.
carrier frequencies.

clas teem esi rae

tsp tty
detail.
1. Draw and explain WLL architecture In
————

gies?
2. What are various WLL technolo
3 . What are different WLL types?
4 - Compare CT-2,DECT,PHS?
 ) Explain the feature of given component in MANET architecture
riWSN
the given
of te
Explain charac starchit
ic s,
ecture
Describe the given design challeng WSN,
esin
- thm.
Classify the given clustering algori
m,
= State the procedure of scheduled maintenance of the given syste
 and Mobile Network
| __spemn npeme teerreittic.
ogy Formation:

given neighbourhood. depends on the interaction among communicating entities in a

Thus, in general, before a node Start
of nodes that
, it must discover the set
3 ¢ 4 ‘ are
within its direct communication i
‘ : ommunicating

internal data structure so that it ca n re Once this infor mation is gathered, the node keeps it in an
rent networking activaudities such as routing.
the behaviour of an Ad-hoc node : © used in diffe nodes because it
sens e the med ium befo re it €pen ds on the behaviour of its neighbouring
must i interfering Tange,
: Starts transmitti
which can cause collision at the other nodes ee a eS ELE:
Nod e discovery Ty ca can be achiieved with
i periodic
transmission of beacon packets or with
snooping on the channel to dete promis. cuous
2, Packet F orwarding Algori ct the com mun i cation activity.

that chooses the one to

PA EDOOE Vers Oh a routing protocol is the packet forwarding algorithm
be used to forward the data packet among neighbouring nodes.
+ The forwarding algorithm implements a forwarding goal that may be, for instance, the shortest
average hop distance from source to destination.
» In this case, the set of potential nodes may include only those in direct communication range from
the current node or also the set of possible nodes in the route to the destination.
« The forwarding goal may also include some QoS parameters such as the amount of energy available
at each node. The following forwarding algorithms consider only nodes that are in direct
communication range of the node that has a data packet to be forwarded, as depicted in Fig 5.2.
+ The Most Forward within Radius (MFR) forwarding algorithm chooses the node that maximises the
distance from node S to point p. In this case, as depicted in Fig 5.2 it is node 1.
+ Contrarily, the Nearest Forward Progress (NFP) forwarding algorithm chooses the node that
minimises the distance from node S to point q. Here, it is node 2. The Greedy Routing Scheme (GRS)
uses the nodes geographical location to choose the one that is very close to the destination node D.
And here it is node 3.
* The Compass Selecting Routing (COMPASS) algorithm chooses the node that minimises the angle,
but considers the nodes that are closer to node D. Hence, it is node 4. The random process forwarding
algorithm, as the name suggest, chooses a random node that is in direct communication range from
S.
 Wireteas and Mobile Network 54 Mobile

* The Partial Topology Knowledge Forwarding (PTKF) algorithm chooses a node using @ localised
shortest path weighted routing where routes are calculated based on the local topological view and
considering the transmission power needed to transmit in that link.

Features of MANET
* It is an infrastructure less IP based network of mobile and wireless machine nodes connected with
the radio, In operation, the nodes of a MANET does not have centralized administration mechanism.
* It is known for its routeable network properties where each node acts as a “Router” to forward the
traffic to other specified node in the network.
Characteristics of MANET:
1, In MANET, each node acts as both host and router, Thus it shows autonomous behavior.
2. Multi-hop radio relaying- When a source node and destination node are out of the radio range,
the MANETs are capable of multi-hop routing.
3. It posses distributed nature of operation for security, routing and host configuration. A
centralized firewall is absent.
4. The nodes can join or leave the network anytime, making the network topology dynamic in
nature,
5. Mobile nodes are characterized by lesser memory, power and lighter in weight features.
6. The reliability, efficiency, stability and capacity of wireless links are often inferior when
compared with wired links. This shows the fluctuating link bandwidth of wireless links.
7. It needs mobile and quick behavior which needs minimum human intervention in configuring
the network.
8. All nodes possess identical features with similar responsibilities and capabilities and thus it

i
ors a completely symmetric environment.
8 High user density and larger level of user mobility,

a
10. Nodal connectivity irregular:

I
 le ork

automatically establ
ishing 4 data
rescuers are already carrying, theip n etwork with the communications equipment that the
ship-to-ship Ad-hoc mobile seat job mad narios include ¢.g-
low lee Mun cat ion © easier. Other commercial sce
Low Level: Appropriate Wavetions, law enforcement, etc,
communicate directly to exch Pplication might be in domestic networks where devices can
tard, sports stadium, boat a i: 8¢ information, Similarly in other civilian environments like

applications. ome aircraft, mobile Ad-hoc communications have many

4.
pplication for MANETS includ
e wide range computing. By
ey data to others, data networ
kse may be extended far
ructure. Networks may be mad
more widely available bey
andondeasthe
ier

Vehicular Area Network;

Ad-hoc network is useful in forming network among different
vehicles on the roa
d and can Propagate in
in determining nearby facilities formation like accidents, congestion. It is also helpful
such as 8as station, restaurants, hospitals and other facilities.
Personal Area Network: PAN
is short range, localized network where nodes are associated with a
,
Ste paren Bees could be attached to someone's cellphone laptop and television and so
on.
 Wiretess and Mobile Network 5.6 _Mobile Ad-hoo Networks _..
* This helps the network designer and architect to optimize and select the right
network hardereay, q
software, and features to perform specific roles for that network
layer.
* Hierarchical models apply to both LAN and WAN design. A typical enterprise hierarchical
campus network
LAN
design includes the following three layers:
(i) Access Layer: Provides workgroup/user access to the networ
k
(ii) Distribution Layer: Provides policy-based connectivity and controls the boundary between the
access and core layers
(iii) Core Layer: Provides fast transport between distribution switches within the enterprise campus
Core
Distribution

Access

/ Fig. 5.5 : Hierarchical network architecture 1

_* The benefit
of dividing a flat network into smaller, more manageable blocks is that local traffic
 -dictable manner since nodes are free to move.
change in topology made kn OWN to other nodes so that outdated topology information can be
updated or removed,
enges in MANET;
4, Routing: Since the topology of the hetwork is constantly changing, the issue of routing packets
between any pair of nodes becomes a challengi kb routes between nodes may
potentially contain multiple hops, which is mor ~/ Decieyll canara munication.
’ e complex than the single hop com
9, Security and Reliability: An Ad hoc network has its
particular security pr oblems due to nasty
| neighbor relaying packets, The feature of distributed operation requires different schemes of
authentication and key management, Further, wireless link characteristics introduce also
reliability problems, because of the limited wireless transmission range, the broadcast nature of
| the wireless medium, mobility-induced packet losses, and data transmission errors.
| 3, Quality of Service (QoS); Providing different quality of service levels in a constantly changing
environment will be challenge. The inherent stochastic feature of communications quality in 4
MANET makes it difficult to offer fixed guarantees on the services offered to a device. An
| adaptive QoS must be implemented over the traditional resource reservation to support the
multimedia services,
4, Internetworking: Addition to the communication within an Ad hoc network, inter-networking
between MANET and fixed networks is often expected in many cases. The coexistence of routing
protocols in such a mobile device is a challenge for the harmonious mobility management
tion-related functions
5. Power Consumption: For most of the mobile terminals, the communica
should be optimized for lean power consumption. Conservation of power and power-aware
routing must be taken into consideration.
in the wireless
6. Restricted Wireless Transmission Range: The radio group will be restricted
a bound network
networks and as a result data amounts it can provide much slighter than what
use bandwidth in
can provide. This involves routing procedures of wireless networks must be
. The
ideal way. This can be achieved through protecting ine overhead as minimum as conceivable
the
restricted transmission range also enforces restraint on routing procedures for sustaining
topographical information. Particularly in MANETs because of regular variations in topology,
results
preserving the topological data for every node includes more controller overhead which
in additional bandwidth depletion.
7. Time-Varying Wireless Link Characteristics: Wireless channel is liable to a range of broadcast
disorders such as path harm, declining, intervention and obstruction. These features resist the
of these cordless transmissions. The range of which these
series, data rate, and consistency
features disturb the transmission that rest on atmospheric situations and flexibility of receiver
and transmitter. Even two dissimilar key restraints, Nyquist’s and Shannon’s theorems that rule
over capability to communicate the information at diverse data degrees can be measured.
Errors: Adsion
8, Packet Losses due to Transmis hoc wireless networks practices very advanced
packet damage due to reasons such as extraordinary Bit Error Rate (BE wireless channel,
in theR)
ee rashes because of the existence of unseen terminals, occurrence of interventions,
 9. Mobility-Induced Route Changes; The systern topography in ad hoc wireless network is
extremely active be-cause of node movement; as a result, a constant meeting undergoes .
numerous pathway breakages. Such position often results in regular path alterations. So
flexibility administration is massive investigation theme in ad hoc networks.
10. Mobility-Induced Packet Losses; Communication contacts in an Ad hoc network are insecure
such that con-seductively conservative procedures for MANETs over a great damage frequency
will suffer from performance deprivation. Though, with large frequency of inaccuracy, it is
problematic to supply a data-packet to its target.
11. Battery Constraints: It is due to restricted resources that arrange main limitation on the mobile
devices in an ad hoc network. Nodes which are contained in such network have restrictions on
the supremacy foundation in order to preserve movability, dirnension and capacity of the node.
Due to accumulation of power and the processing capacity and less
make the nodes heavyweight
portable. Consequently only MANET devices have to use these resources.

EERG Wireless sensor Network (WSN)

of spatially distributed
* A Wireless Sensor Network (WSN) is a wireless network consistingconditions.
autonomous devices using sensors to monitor physical or environmental
* A WSN system incorporates a gateway that provides wireless connectivity back to the wired world
and distributed nodes .The wireless protocol you select depends on your application requirements
* Some of the available standards include 2.4 GHz radios based on either IEEE 802.15.4 or IEEE 802.11

Ni 5 is) be defined as a self-configured and infrastructure-less

 2 and Mobile Network 59
Wireles5®
| ware , a
f 9, neal of New Device; WSN can accommodate new devices in the network any time
Addition . ; : yt :

Save Cost: Wireless sensor netwo rks savea lot

3,
relatively cheaper then winus of wiring cost and sensors like PIR detectors are 7
i ‘4
WSN : "
pisadvantage s of
‘
1. a ae are not secure as compared to wired networks. Hackers can easily hack the

2, Battery Issue: Nodes need to be charged at regular intervals. ...

3. Low Communication Speed: Communication speed is comparatively low than the wired network.

* A Wireless Mesh Network (WMN) is amesh network created through the connection of
wireless access points installed. at each network user's locale. Each networ k user is also a provider,
forwarding data to the next node,
e The networking infrastructure is decentralized and simplified because each n ode
need only transmit
as far as the next node.
areas and small businesses operating
¢ Wireless mesh networking could allow people living in remote
in rural neighborhoods to connect their networks together for affordable Internet connections.
* Wireless Mesh Network (WMN) has recently being emerged as trend for the next generation wireless
network.

Mesh router with gaetway

Mesh router

Mesh router Mesh client

Mesh client
; : Mesh client
Wired link — — — — Wireless link

Fig. 5.8 :Wireless Mesh Network (WMN)

* Wireless Mesh Network (WMN) combines multi hop and multi cell fashion with no mobility of cells
* Wireless Mesh Network (WMN) employs AP known as IGW (Internet gateway) to provide network
access service for Mobile Host (MH). a
* To have larger coverage, WMN employs a relay station known as “Mesh Router “in Ad-hoc mode. Ad
hoc network technology enables the MR to establish a mesh like network with no mobility to MR. ,
 Bg Applications of WSN era
* Wireless Sensor Networks (WSN) is an important and exciting new te
for improving many current applications in medicine, transporta
tion,
process control, and the military as well as creating new
revolutionary
global-scale environmental monitoring, precision agric
ulture, ee
* home and assisted living medical care, smart buildings and
cities, and numerous f
applications. In fact, it is difficult to consider any major application area that cannot
WSN technology.
ae!
Typically, WSN are composed of large numbers of minimal capacity sensi
ng, computing,
commu nicating devices and various types of actuators, WSN
operate in complex and noisy
world, real-time environments,

Fig. 5.9: Application of Wireless Sensor Network (WSN) a

* To date, research and real-world implementations have produced many excellent low lev:
mechanisms and protocols to collect, transport, perform sensor fusion of this raw data
with control actions. =
4. Surveillance Applications: VigilNet is a military wireless sensor network that acq
verifies information about enemy capabilities and positions of hostile targ
successfully designed, built, demonstrated, and delivered to the Defense Int
 ing the close by
gclusters,
nodes in a cluster can transm
it directly to their Tes
mediate sensor nodes .This mi
nimizes the energy consum
Head (CH) also need to e
transmit information to
med in wireless transmission is dir the other Cluste
ectly proportional to thesquare
iesensor nodes acting as a Cluste
r Head (CH).
ee a
:

Base station/Sink f

Cluster 1.
 Network BAQ
a
sN) into clust
There! fore it is desirable to partitio
n a Wireless Sensor Network (w a n ced to" " |
e th a n d i s t
reachable by path length less umption,
all the sensor nodes in a cluster ra ll en ergyataconswith in each
d that mini mizes a s
e Determining optimal value of distance to ane
take into account of data ee: e oe
comple x problem and it also ne ed to le latency: nant
n clu ste rs, fre que ncy of tra nsm iss ion, maximum allowable e
and betwee
* To select Cluster Head (CH) usually the
sensor node
ae
7 its cluster
As Cluster Head (CH) does aggregation of data eae
neighbors) is selected,
schedule to its members andt ae sane oe
members, it is usually trusted with transmission
wae ue e
Head (CH) needs to perform more functions than sensor nodes it may run
Cluster
Cluster Head (CH) has been sugs
much faster rate, Hence dynamically changing
ble.
distribute energy consumption as evenly as possi

[ween Characteristics of WSN e numerous

real -wor ld unat tend ed phys ical environment to measur ante
WSN is currently used for cient deploym
of WSN must be considered for effi
parameters. So, the characteristics
network.
ibed as follows:
e Thesignificant characteristics of WSN are descr measure
thousands of sensor nodes are deployed to
4. Low Cost: In the WSN normally hundreds or e network the cost of the
to reduce the overall cost of the whol
any physical environment. In order
sensor node must be kept as low as possible.
for different purpose such as computation,
2. Energy Efficient: Energy in WSN is u sed
er for
e energy compare to any oth
communication and storage. Sensor node consumes mor any
communication. If they run out of the power they ofte 1
become invalid as we do not have
development s hould consider the pow
er
option to recharge. So, the protocols and algorithm
consumption in the design phase.
using ra dio waves over a wireless
3. Communication Capabilities: WSN typically communicate
with narrow and dynamic
channel. It has the property of communicating in short range,
unidirectional. With the
bandwidth. The communication channel can be either bidirectional or
ly. So, the
unattended and hostile operational environment it is difficult to run WSN smooth
y and
hardware and software for communication must have to consider the robustness, securit
resiliency.
4. Security and Privacy: Each sensor node should have sufficient security mechanisms in order to
prevent unauthorized access, attacks, and unintentional damage of the information inside of the
sensor node. Furthermore, additional privacy mechanisms must also be included. Distributed
sensing and processing: the large number of sensor node is distributed uniformly or randomly.
WSNs each node is capable of collecting, sorting, processing, aggregating and sending the data to
the sink. Therefore the distributed sensing provides the robustness of the system.
5. Dynamic Network Topology: In general WSN are dynamic network. The sensor node can fail for
battery exhaustion or other circumstances, communication channel can be disrupted as well as
the additional sensor node may be added to the network that result the frequent changes in the
network topology. Thus, the WSN nodes have to be embedded with the function of
' reconfiguration, self-adjustment.
6. Self-Organization: The sensor nodes in the network must have the capability of organizing
themselves. As the sensor nodes are deployed in an unknown fashion in an unattended and.
 intermediate node,
8. nesta ccna iat Vem
highly dependent on the applic
ation ranges from military,
sector. The nodes are deployed ran vironme:
domly and spanned depending on the
9. Robust Operations: Since the sen sors are going to be dep
type
hostile environment. So, the sensor nodes loyed over
have to be fault and error toleran
nodes need the ability to self-test, self-cal
ibrate, and self-repair Small physical
are generally small in size with the restricted range. Due to its size its energy is
makes the communication capability low.

Block Diagram of Sensor Node

*« A Wireless Sensor Network (WSN) is a wireless network consisting of spatially d
autonomous devices using sensors to monitor physical or environmental conditions.
A WSN system incorporates a gateway that provides wireless connectivity back to the wired v orld
f
and distributed nodes.
The block diagram of sensor node is shown in Fig. 5.11.

Fig. 5.11: Wireless Sensor Node

Sensors: Sensors are used by wireless sensor nodes to capture data from their environment. TI
hardware devices that produce a measurable response to a change in a physical con
temperature or pressure. Sensors measure physical data of the parameter to be monit ;
specific characteristics such as accuracy, sensitivity etc. The continual analog signal produced|
sensors is digitized by an analog-to-digital converter and sent to controllers for further proce

wireless se
autonornous and operate unattended, and be adaptive to the environment. As
with a limited
are typically very small electronic devices, they can only be equipped
:
andr 1.2-3.7 volts.
less than 0.5-2 ampere-hou = = = 828
Sensors are classified into two categories: PassiveandActivesensors.
the 54
1 Passive sensors sense the data without actually pens

)
hi.
Wireless and Mobile Network 5.14

ve sensors. Each ae ae
Most theoretical work on WSNs assumes the use of passi
es nee of
area of coverage for which it can reliably and accurately report the particular _ 4 e Sp ae
in sensors are: signal ae ne
observing. Several sources of power consumption ae
g-to-digital ©
physical signals to electrical ones, signal conditioning, and analo encore
as 20 nodes per cubic meter.
density of sensor nodes in the field may be as high a sick
sses data and controls ue
Microcontroller: The controller performs tasks, proce oller is a mlesesee ca ie a
While the most common contr
other components in the sensor node.
se desktop microprocessor,
alternatives that can be used as a controller are: a general purpo ion Speci
asics (Applicat pecific
signal processors, FPGAs (Field Programmable Gate Array) and
Integrated Circuits). s because of its
such as sensor node
> Amicrocontroller is often used in many embedded systems ming, and low aepower
low cost, flexibility to connect to other devices, ease of program
consumption. A general purpose microprocessor generally has higher forapower consumption than a
choice sensor node. gs.
microcontroller;therefore it is often not considered a suitable
broadband wireless communication applications,
o Digital Signal Processors may be chosen for
modest: i.é., simpler, easier
but in Wireless Sensor Networks the wireless communication is often = less
to process modulation and processing tasks of actual sensing of data
the signal
complicated. Therefore, the advantages of DSPs are not usually of much importance to wireless
to requirements, but this
sensor nodes. FPGAs can be reprogrammed and reconfigured according
takes more time and energy than desired. .
often make use of ISM band, which gives free radio, spectr um allocation
Transceivers: Sensor nodes
and global availability. The possible choices of wireless transmission media are radio
frequency (RF), optical communication (laser) and infrared.
n and are sensitive to
o Lasers require less energy, but need line-of-sight for communicatio
it is limited in
atmospheric conditions. Infrared, like lasers, needs noantenna but
t that fits
its broadcasting capacity. Radio frequency-based communication is the most relevan
n frequencies: 173,
most of the WSN applications. WSNs tend to use license-free communicatio
433, 868, and 915 MHz; and 2.4 GHz.
o The functionality of both transmitter and receiver are combined into a single device known as
a transceiver. Transceivers often lack unique identifiers. The operational states are transmit,
receive, idle, and sleep. Current generation transceivers have built-in state machines that
perform some operations automatically. Most transceivers operating in idle mode have a power
consumption almost equal to the power consumed in receive mode. Thus, it is better to
completely shut down the transceiver rather than leave it in the idle mode when it is not
transmitting or receiving. A significant amount of power is consumed when switching from
sleep mode to transmit mode in order to transmit a packet.
Memory: Flash memories are used due to their cost and storage capacity. Memory requirements are
very much application dependent. Two categories of memory based on the purpose of storage are:
4, User memory used for storing application related or personal data and
2. Program memory used for programming the device. Program memory also contains
identification data of the device.

Different Types WSN Architecture

* Depending on the environment, the types of networks are decided, Hence different types of WSNs
include Terrestrial WSNs, Underground WSNs, Underwater WSNs, Multimedia WSNs and Mobile
WSNs.
wireless and Mobile Network
_5A5
1. Terrestrial WSNs:
qerrestrial WSNs are capable of comm
unicating base stations efficiently, and consist of hundreds to
s deployed either in unstructured (Ad hoc) or structured
thousands of wireless sensor node
(preplanned) manner,
In an unstructured mode, the sensor node
8 are randomly distributed within the target area that is
dropped from a fixed plane,
and 2D, 3D
oe S aa sens mode considers optimal placement, grid placement,
placement models, In this WSN, the battery power is limited; however, the battery is equipped with
solar cells as a secondary power source,
The Energy SaibeXVaOH of these WSNs is achieved by using low duty cycle operations, minimizing
delays, and optimal routing, and so on.
Underground WSNs:
The underground wireless sensor networks are more expensive than the terrestrial WSNs in terms of
deployment, maintenance, and equipment cost considerations and careful planning.
The WSNs networks consist of a number of sensor nodes that are hidden in the ground to monitor
underground conditions. To relay information from the sensor nodes to the base station, additional
sink nodes are located above the ground.
The underground wireless sensor networks deployed into the ground are difficult to recharge. The
sensor battery nodes equipped with a limited battery power are difficult to recharge.
In addition to this, the underground environment makes wireless communication a challenge due to
high level of attenuation and signal loss.
Under Water WSNs:
More than 70% of the earth is occupied with water. These networks consist of a number of sensor
nodes and vehicles deployed under water.
Autonomous underwater vehicles are used for gathering data from these sensor nodes. A challenge
of underwater communication is a long propagation delay, and bandwidth and sensor failures.
Under water WSNs are equipped with a limited battery that cannot be recharged or replaced. The
issue of energy conservation for under water WSNs involves the development of underwater
communication and networking techniques.
Multimedia WSNs:
Multimedia wireless sensor networks have been proposed to enable tracking and monitoring of
events in the form of multimedia, such as imaging, video, and audio.
These networks consist of low-cost sensor nodes equipped with microphones and cameras. These
nodes are interconnected with each other over a wireless connection for data compression, data
retrieval and correlation.
The challenges with the multimedia WSN include high energy consumption, high bandwidth
requirements, data processing and compressing techniques. In addition to this, multimedia contents
require high bandwidth for the contents to be delivered properly and easily.
Mobile WSNs:
These networks consist of a collection of sensor nodes that can be moved on their own and can be
interacted with the physical environment. The mobile nodes have the ability to compute sense and
3
communicate.
The mobile wireless sensor networks are much more versatile than the static sensor networks. The
advantages of MWSN over the static wireless sensor networks include better and improved coverage,
better energy efficiency, superior channel capacity, and so on,
 Fig. 5.12: Types of WSN architecture
Energy Efficiency in WSN 3 ‘ee
* Fig. 5.13 shows classification of energy efficiency mechanism in WSN.

Fig. 5.13: Classification of energy efficiency mechanism in WSN ’

The classification of Energy efficiency mechanisms in WSNs can be classified as WSN Protocol
Stack, WSN based Techniques, Sensor Hardware and Cross layer design. a
WSN Protocol Stack: The energy efficient techniques under WSN Protocol Stack can be further i
classified as physical layer, mac layer, network layer, transport layer and application layer, _
1, Physical Layer: Modulation, transmission and receiving techniques are importance of
layer. In multi hop Wireless Sensor Network (WSN): Distance, Transmission energy, Moc
Scheme. Energy efficiency can be increased by proper Modulation scheme. ;
2. MAC Layer: The MAC layer has to be responsible for reliability, energy effi
_ throughput and low access delay to optimally utilize the energy-limited 2 Irces
nodes. Maximum amount of energy wasted in MAC protocol operations |
overhearing, control packet overhead and interference. To minimize the ener
WSNs stay efficient MAC techniques like tute es pack

al
 sensor node to sleep/wake up mech
jnvolves in putting the radio t,

sath g a
adependin on saa
netw ork activ or
the besensreferre
makeitys can nodes to altern a:
rred as duty cycling.
g, Network Layer: Routing is the process which finds the path between the sour impo
while initiating data communicationin the network. Routing is much more
other networks compared to WSNs. ve
Table 5.1: Radio ch
dio M se
Transmitter Electronics (ElecTx)
Receiver Electronics (E-elecRx) 50nj/bit pak
(Eelec = EelecRx = EelectTx) he
100 pJ/bit/m? a
Transmit Amplifier (camp)
Idle (Eidle) 40nj/bit "
Sleep ?
sleep
The energy spent in communication (transmission and reception) is much higher than Idle and
state of the sensor node. Energy efficient routing can be done through Cluster based hierarchical
Routing, flat routing, multipath routing, and geographical routing. ay
LEACH Protocol is a kind of cluster-based routing protocols, which includes distributed cluster ‘te
role to
formation. LEACH randomly selects a few sensor nodes as cluster heads (CHs) and rotates this
evenly distribute the energy load among the sensors in the network. The idea is to form clusters of
the sensor nodes based on the received signal strength and use local cluster heads as routers to the
sink. In LEACH, the CH nodes compress data arriving from nodes that belong to the respective
cluster, and send an aggregated packet to the BS in order to reduce the amount of information that
vision
must be transmitted to the BS. LEACH uses a Time division multiple access (TDMA) and code-di
multiple access (CDMA) MAC to reduce inter-cluster and intra-cluster collisions. Cluster heads
change randomly over time in order to balance the energy dissipation of nodes
or
. Transport Layer: When multiple nodes want to transmit data through the same channel at a time
when the routing node fails to forward the received data to the next routing nodes congestion
occurs, Congestion and data loss occurs at nodes which are nearer to the sink nodes. Energy saving
can be achieved in transport layer of WSNs through energy aware congestion avoidance, energy
efficient load sharing and energy efficient reliable mechanisms between end to end communication
,
in WSNs,
-

. Application layer: Energy saving in the application layer is achieved through application service —
d from data-retri Fh
ae

which aims at energy conservation, by caching mutable data obtaine

locations that minimize the sum of request and update traffic & asynchronously multic:
’

updates from sensors to observers reduces the total number of packet transmissions in the
WSN Based Techniques ; ™
* Energy Efficient Deployment in WSN : The optimal deployment of nodes adds to the lif
Network, along with determination of deployment cost, coverage, connectiv
deployment is important to achieve load balance and prolong the network lifetime
 5.18 *
in WS Ns is to cover a _
of the area covera ge
¢ Energy Efficient Coverage in WSNs: The main objective
athonpoien region
nt ofethe hat d to
neee
n all spa ce poi nts wit hin the sen sor fiel Seeac
) and
d), ao
lec tio of
: ion (the col
reg
) wi ; :
be monitored. Point coverage is to cover a set of point (target sensor nodes’ exact positions, which
focuses on deter minin g
monitored. The point coverage scheme ts). The
of immobile Poe (targe
guarantee efficient coverage application for a limited number lifetime
coverage issues improve minimization of power utilization of WSNs and WSNs
Sensor Hardware
The energy consumption in WSN hardware involves three different components
4. Sensing Unit (Sensing Transducer and ADC)
2. Communication Unit (Transmitter and receiver radio)
3. Computing and Processing Unit
this part depends on the Hardware and
o Sensing Transducer: The energy consumption of
of the total energy consumed.
Application. Sensing energy is the small fraction31pJ/8 bit-sample at 4volt supply. The standby
ADC: ADC for sensor consumes only 3.1pW,in
power consumption at 1V supply is 41pW.
d can be
Transmission Energy: Transmission energy transmits a k-bit message to distance
computed as:
Erx(K,d) = Evetec.(k)+e. k.d?
k = no. of bits per messages
d = distance between the SN
E.ec = Transmission electronic energy consumption.
Receiver Energy: To receive k bit message the energy consumed Is
Epx(k) = Ectec-(K)
r with
o Computation : The computing unit associated with a WS is a microcontroller /Processo
memory which can control and operate the sensing ,computing and communication unit.
The energy consumption of this unit has mainly two parts: Switching Energy, Leakage
Energy.
Switching Energy is given by
Switching energy = Eswitch=Ctotal*vdd*
Where,
Vdd = supply voltage.
Ctotal = Total capacitance switched by computation.
o Leakage Energy: This is the energy consumed when no computation work is done.
The energy consumed in one bit of data can be used to perform large number of arithmetic
operations in the sensor processor.
Residual Energy: the remaining energy of sensor node is known as residual energy which
Oo

reflects how long the sensor node can perform all its functions correctly.

Designing Challenges in WSN

Wireless Sensor Network (WSN) is special case of ad-hoc networks with reduced or no mobility and
are known as “Data Centric”. This means, unlike traditional ad hoc network where data is requested
from specific node or location, data is requested based on sensed attributes.
The use of particular type of query might depend on the application requirements. The major factors
that need to considered while designing sensor network are listed below:
aa SSS

S19
and Mobile Network
— dt
1. § calable and Flexib} * Architecture: In the sensor network the number of sensor nodes deploye: d
ay be order of
Pccrtminatin fe en ; of nallione 50 SE Weer aes ae a
= See
the network does not affect elastin ne ae we
more n oe and routing. In other words, the networkal must ee =
stability. Introducing network means that addition commu n on
into the
messages will be excha nged, so odes
that these nodes are integrated into the existing network.
2, Error-Prone Wireless Medium: Since sensor networks can be deployed in different situations,
the requirements of each different applicati Py Id consider ; that
the wireless medium can b pplication may vary significantly. We shou
An attacker interferes
affected by noisy environments.
By knowingly and causes eno 7 a
aul: Tolanae ugh noise to affect the communication. ai
: ee ee and Adaptability: Fault tolerance means to maintain sensor network
node because in sensor network
functionalities without any interruption due to failure of sensor node doesn’t affect the overall
every node have limited power of energy so the failure of single
new links in case of node failure oF
task of the sensor network. Adaptable protocols can establish |

link congestion. Network can able to adapt by changing its connectivity in case of any fault. In
of
that case, well- efficient routing algorithm is applied to change the overall configuration
network. j
icate
4. Infrastructure: Sensors network are infrastructure less in which nodes can commun
directly with base station. It utilizes. multi-hop radio relaying and number of base station
depends upon area covered by node and its radio range.
5, Node Deployment: Sensor network can be deployed randomly in geographical area. After
. In sensor network
deployment, they can be maintained automatically without human presence
ent or a sparse deployment. In
node deployment falls into two categories either a dense deploym
targeted field while in a
dense deployment we have relatively high number of sensor nodes in the
the cost of sensor nodes increases
sparse deployment we have fewer nodes and-it is used when
ent is used when it is important
and prohibited the use of dense deployment. The dense deploym
for covering an area.
to detect the every moment or when we have multiple sensors
It must support maximum
6. Real Time: Achieving Real-time in WSN is difficult to maintain.
parameters. This issue can affect time |
bandwidth, minimum delay and several QOS

synchronization algorithm.
yed without any topology and they are
7. Dynamic Changes: As in sensor network nodes are deplo
failure of nodes. Thus, unlike traditional
adaptable to changes due to addition of new nodes or node
the channel throughput or minimize the
networks, where the goal is to maximize
to extend the system lifetime and the system
deployment, but in a sensor network focus is
robustness. ;
it is equipped with |
8. Power Consumption : Wireless sensor node is microelectronic device means
power. Hence power |
a limited number of power source. Nodes are dependent on battery for their
conservation and power management is an important issue in wireless sensor network. Due to
aware protocols and algorithm for
this reason researchers are focusing on the design of power
|
|

sensors network. é.
we know that in the sensor network we
9, Production Cost: As the name suggests production cost,
will be very high then the cost of over all
have large no of nodes deployed, so if a single node to
network will be very high. As a result the cost of each sensor node has to be kept low. In order
d be less. As a result the cost of sensor
make sensor network feasible the cost of sensor node shoul
issue.
node will be a very challenging
 11, Hardware Design: While designing any hardware of sensor jetwork, it | =
efficient. Hardware such as micro-controller, power cont
androl,
communic | nar
design to consume less energy. ae co cecleaalaes
12, Limited Computational Power and Memory Size: It is another factor that affects WSN
sense that each node stores the data individually and sometime more than one node stored s
data and transferred to the base station which waste the power and storing capacity of ae se
we must develop effective routing schemes and protocols to minimize the redundancy in the i 1

network,
13. Operating Environment: Sensor nodes are deployed densely either very closed
or inside the
phenomenon which is to be observed. These nodes may work under-busy interaction, at the
bottom of an ocean, in the interior of a large machinery, on the surface of an ocean during a
tornado, in a home or large building and in a large warehouses. (
14. Simplicity; Simplicity is an important point in the wireless sensor network since sensor nodes
are small and there is restriction on the utilization of energy as they are energy dependent so the ~
computing and communicating software used in the nodes should be computation efficient and
less in size than the traditional software in the network
15. Quality of Service: It means data should be delivered within time period. Some real time sensor
applications are based on time means if data should not be delivered on time from the moment it
is sensed; the data will become unusable for e. g. fire detection requires good quality of services.
16. Security: Security is very important parameter in sensor network since sensor networks are data
centric so there is no particular id associated with sensor nodes and attacker can easily inserted
himself into the network and stole the important data by becoming the part of network without
the knowledge of sensor nodes of the network. So it is difficult to identify whether the
information is authenticated or not.

Internet of Things (IoT)

* Nowadays many companies are jumping for “Internet of Things”. Even Indian Government came up
with policy paper in their Ministry of Information Technology. By looking towards words, there are
two words, one is “Internet” and other word is “Things”,
* In simple way we can say “Internet of things” is to do operations(things) smartly using Internet.
What are these operations, these operations can be any intelligent work which will induce smartness
in the devices.
e For example our home made “electric meters”, now company person is coming at every bodies home
to read your power consumption.
¢ If Electric meter started sending your electric consumption to directly to computer server (cloud
server), we have saved so many man hours which we can use for other work or reduce work force so
that electric companies can become more competitive. ts
* The definition ofa “Thing” in the Internet of Things varies a lot. “Thing” as an embedded computing
device (or embedded system) that transmits and receives information over a network for the
purpose of controlling another device or interacting with a user.
i eae aing signals to theGateway. Th i
- gris not necessary that Devices should se
yariety of ways. There should be moreso x
Networks. ee
technologies. Other best part of IoT is Local
comparison between MANET, WSN and IoT: <hiaecen
Table 5.2 ie
; rhe em
Number of sensor nodes or
1 Large
: in q quantity Net
quantity’ qui
ae
=
2. Dep onc type Very much dense Scattered a E !
3. Rate of failure Prone to failures Very rare Less _
Change in network ' ma a
4. topology Dynamically _ *Dynamically ee a. ‘
* to Point
Point (P2I
Peertopeerand |e Star '
5.
‘anti
Communication mode : Peer to P ‘
aic
Of
sal
;
end to end e Mesh
é e Hybrid [24] ee
De
Not replaceable ee
Batte ble - Replaceable |
6. Reps a ae
zm /not rechargeable
NGvuIean Usionetn ti
; Identifiers (IDs) used in the Unique IDs Pipl 4
: menor o unique IDs

Centric mode Data centric Address centric Both _ 2. hae

8.
Possible Not suitable Possible |
9. Fusion/Aggregation
riraited Met lied inst a
‘a: Computational papaciies
Limited saa
and memory requirement
Higher Moderate ie 43a
11. | Data rate support provided Lower
Redundancy High Low Low. sree
12.
Zighee) JERE ZigBee,
Sok RFID,
Ve Blu_ etooth [e
A
13, Standards 802.15.4,1SA100, | - IEEE 802.11 ihe
IEEE 1451 and BACnet
Needed only if Needed as Absence of access tothe ve
Fault tolerance ' ah
nodes exhaust mobility running code,

14, available energy increases Denial-of-service

or are moved heterogeneous w
hard a 4 oy |e ‘

Short Long ‘Lon

15.| Communication Range
Close to humans bd
roe e.g. laptops, PDAs
16. Interaction interaction with manent ee 7
is the envi vironment | Sata sat
i terminals
 > 2 le 5.3 : (

4 _Number of sensor nodes Large ——

2 Deployment Densely deployed = _
3, Failure rate Prone to failures _Ver _
4. Topology Dynamic ee
5. Communication paradigm Peer to Peer Peer topeer and ————
6. Battery Not replaceable /not Replaceable =
rechargeable :
7. Identifiers No unique identifiers _ Unique identifiers be
8. Centric Data centric Address centric
9. Fusion / aggregation Possible Not suitable
10. Computational capacities Limited Not limited
and memory
11, Data rate Low High
12, Redundancy High Low
a. Routing protocols Flooding, Gossiping, Flat Pro-active, Reactive, Hybrid
Routing, Hierarchical,
Location based
14. Standards ZigBee, IEEE 802.15.4, IEEE 802.11
ISA100, IEEE 1451
15, Fault tolerance Needed only if nodes Needed as mobility
exhaust available energy or increases
are moved
16. Communication Range Short

EQUIVALENT PROTOCOL LAVER ARCHITECTURE FOF Sra W ee eee : ee ay

« Fig.5 .14 shows WSN protocol architecture.

* The most common WSN architecture follows the OSI architecture Model. The architecture of the
WSN includes five layers and three cross layers.
* Mostly in sensor network require five layers, namely application, transport, network, data link
and
physical layer. The three cross planes are namely power management, mobility management,
and
task management.
* These layers of the WSN are used to accomplish the network and make the sensors work together in
order to raise the complete efficiency of the network

Fig. 5.14: WSN Protocol Architecture

F wirelessand Mobile Network 5.23 .
| physical Layer:
»_ the physical layer provides an edge for transferring a stream of bite above py
| nedit ’
ct on
layer is responsible for the sele ncy,
frequency, generation of acarrier freque
detection, Modulation and data mane

802.15.4
IEEE cost,
+ low is suggested as typical fort low rate particular areas and wireless sensor network withhe ip
ty, the range of communication to improve the battery life.
power consumption, densi
pata Link Layer:
Access
« The data link layer is responsible fo vr multi
plexing of data streams, frame detection, nae
l j |
Control (MAC) and error control,
: = meant hl at ave tt ana sensor nodes can be mobile, the MAC protocol must be power
sion with neighbors’ broadcast.
Transport Layer:
+ The ee of the transport layer is to deliver congestion avoidance and reliability where a lot of
protocols intended to offer this function are either practical on the upstream.
° These protocols use dissimilar mechanisms for loss recognition and loss recovery. The transport
layer is exactly needed when a system is planned to contact other networks.
why
« Providing a reliable loss recovery is more energy efficient and that is one of the main reasons
Event driven.
TCP is not fit for WSN. In general, Transport layers can be separated into Packet driven,
Network Layer:
based on the application, but
¢ The main function of the network layer is routing, it has a lot of tasks
actually, the main tasks are in the power conserving, partial memory, buffers, and sensor don’t have
a universal ID and have to be self-organized.
to
¢ The simple idea of the routing protocol is to explain a reliable lane and redundant lanes, according
a convinced scale called metric, which varies from protocol to protocol.
separate into; flat routing and
* There area lot of existing protocols for this network layer, they can be
& event driven.
hierarchal routing or can be separated into time driven, query-driven
STCP (Sensor Transmission Control
* There are some popular protocols in the transport layer namely
PSFQ (pump slow fetch quick).
Protocol), PORT (Price-Oriented Reliable Transport Protocol and
Application Layer:
and offers software for numerous
* The application layer is liable for traffic management
find positive information. :
applications that convert the data in a clear form to
applications in different fields such as agricultural,
* Sensor networks arranged in numerous
etc.
military, environment, medical,
t Planes:
Power, Mobility and Task Managemen ement, and
management planes monitor the power, mov
* Inaddition, the power, mobility, and task
or nodes.
task distribution among the sens
or node uses its power. When the power level
1. Power Management Planes: It manages how a sens
that it is low in power and
or node broadcast to its neighbors
of a sensor node is low, the sens
rved for sensing.
age. The remaining power is rese
cannot participate in routing mess
ster the movement of sensor nodes; so a route
2. Mobility Management planes: It detect and regi
or nodes can keep track of who their neighbor
back to the user is always maintained. The sens
node are and then sens or node s can balance their power task usage.
sens or the senatng task given to specific regi
on. .
Plan e: It bala nces and sche dule s
3. Task Management all energy |
dinate the sensing task and lower the over
These planes help the sensor nodes coor
consumption.
 Classification of Clustering Algorithms
* There have been several different methods to classify the algorithms used for WSNs |
of the most common classifications are shown in Fig. 5,15, a*~
eterogeneous algorithms ,

Homogeneous algorithms
Centralized algorithms

istribut
Distri ed algalgorithms
buted
Clustering algorithms:
Static algorithms

Dynamic algorithms

Probabilistic algorithms

Non-probabilistic algorithms
Fig. 5.15 : Common Classification Algorithm
* Clustering Algorithms Homogeneous or Heterogeneous Networks: This classification according to
the characteristics and performance of sensor nodes in a cluster. In heterogeneous sensor networks,
all nodes have the same specifications, hardware and processing capabilities. In these networks,
which are common in nowadays applications, each node can be a CH. In addition to these networks,
the CH role can be replaced between the nodes periodically (for the creation of better and more
integrated load balancing energy). Against in heterogeneous sensor networks, generally, there are
two types of sensor, the first type sensors with more processing abilities and complex hardware.
These sensors predetermined as a CH node. The other type conventional sensors, with lower abilities,
which in fact, used to sense the environment properties.
e Centralized or Distributed Clustering Algorithms: These clustering algorithms imply on the
method utilized for shaping clusters. A distributed CH selection and shaping process are the most
suitable way to obtain enhanced flexibility and faster convergence times independent of the number
of nodes of the WSN. This approach is the most efficient method, particularly for large networks.
Also, there are a few approaches using centralized or hybrid method, which one or more coordinate
nodes or base stations (sink), responsible for the break up into detached and control of all network
cluster members. These networks are not appropriate for overall objective large-scale practical
application WSNs. They may be appropriate just for specific targets bounded-scale applications in
which high-quality connectivity and network separation is needed. :
¢ Static and Dynamic Clustering Algorithms: Other conventional classification is static or dynamic
clustering. Process shaping clusters is dynamic (otherwise as static) when it contains regular
(periodic or event-oriented) CH re-election or includes cluster reorganization routine, these
procedures may be effective in order to respond to changes in network topology and only accurately
the cluster topology or proper movement with the purpose CH role between the nodes to obtain
in
energy saving. Dynamic cluster architectures make a better use of the sensors in a WSN
and
naturally result in improved energy consumption management and network lifetime.
* Probabilistic and Non-Probabilistic Clustering Algorithms: This classification based on
cluster
shape parameters can be used to select the CH. These clustering algorithms are divided into two
categories namely. Probabilistic (random or hybrid) and Non-probability (deterministic),
Most clustering algorithms are known, they can be divided into two main categories.
In the
probabilistic clustering algorithm for determining the initial CH, a probability assigned to each
node. Probabilistic clustering algorithms, beyond the more energy-efficient, often running faster at
the convergence and reduce the volume of messages they exchange. In the non-probabilistic
 Bs
:
Wireles s and Mobile Network Mobile Ac-t

r.
clustering es basically criteria (deterministic) more specific for CH selection and cluste
ae take into consideration. These criteria are essentially based on the proximity of adjacent
other closely located nodes.
nodes like (connectivity, degree, etc.) and information received from

per Component of WSN Architecture and Explanation

e Fig. 5.16 shows components of wireless sensor network.

Internat

Sensing unit Processing unit Transmission unit

Fig. 5.16: Components of wireless sensor network

infrastructure-less
Wireless Sensor Networks (WSNs) can be defined as a self-configured and
as temperature, sound,
wireless networks to monitor physical or environmental conditions, such
the network to
vibration, pressure, motion or pollutants and to cooperatively pass their data through
analyzed.
a main location or sink where the data can be observed and
Sensor Node:
could either
A wireless sensor network consists of hundreds and thousands of low-cost nodes which
have a fixed location or be randomly deployed to monitor environment.
Sensors are usually communicate with each other using multi hop approach. The sensor nodes can
communicate among themselves using radio signals. A wireless sensor node is equipped with
ts.
sensing and computing devices, radio transceivers and power componen
The individual nodes in a wireless sensor network (WSN) are inherently resource constrained: they
have limited processing speed, storage capacity, and communication bandwidth.
After the sensor nodes are deployed, they are responsible for self-organizing an appropriate network
n with them.
infrastructure often with multi-hop communicatio
Then the onboard sensors start collecting information of interest. The flow of data ends at special
node called base station (sink).
. Cluster:
ption, which is greatly affected
One of the biggest problem of sensor networks is the power consum
by communication between nodes.
‘sifi .
To solve this aggregation points are introduce in network. This reduces the total number of message
, 3 La
exchanged between nodes and save some energy.
’ a
=.
 its destination ie, base sation,
Another method to save energy is to set nodes to go to ic
needed and wakeup when required,
Base Station (Sink): ;
A base station links the sensor network to another network(like a gateway)to diss
sense for further processing.
Base Station (BS) have enhance capabilities over simple sensor nodes since they mu en
data processing. The communication between base stations is initiated over high bandwidth links.
a
End User:
The data in a sensor network can be used fora wide-range of applications. Therefore, a particulay
application may make use of the network data over the internet, using PDA, or even a desktop
computer.
Wireless sensor devices also respond to queries sent from a “control site” to perform specific
instructions or provide sensing samples.
The working mode of the sensor nodes may be either continuous or event driven. Global Positioning
System (GPS) and local positioning algorithms can be used to obtain location and positioning
information,
Practice Questions
Define MANET.
Lay

What is MANET Topology.

nnpwn

What are the characteristics of MANET.

Write any four applications of MANET.
What are different types of MANET architecture.
What are designing challenges in MANET.
Define wireless sensor network.
wan

Define mesh networking.

Write any four applications of WSN.
. What is clustering of WSN.
SSNSRREBRES

. What are the characteristics of WSN.

. Draw and explain block diagram of sensor node.
. What are different types of WSN architecture.
. Explain energy efficiency in WSN.
. Explain design challenges in WSN.
. Compare MANET, WSN and IOT. ,
. Compare WSN and MANET. a
. Explain ISO equivalent protocol layer architecture for WSN. ie
. Explain classification of clustering algorithm.
. Draw component of WSN architecture and explain each term in detail.
o
N

oe