MOBILE COMMUNICATION

Introduction
Communication is one of the important areas of Electronics and has always
been a focus point for exchanging information among parties at locations
physically apart. There are different modes of communication like written
messages ,speaking to the other party, giving Fax etc.
Multimedia Applications can be used for this purpose. Multimedia is an
integrated interactive storage and retrieval processing system involving audio,
video, computer graphics, animation etc. The three components of
communication are :

1. Contents to be communicated
2. Channel or media through which communication takes place
3. Communication Protocols
 Mobile Communication
Since the time of Morconi Radio Communication has been used
extensively. Since then the society has been looking for acquiring mobility
in communication. Initially the mobile communication was limited
between one pair of users on single channel pair. The range of mobility
was defined by the transmitter power, type of antenna used and the
frequency of operation. With the increase in the number of users,
accommodating them within the limited available frequency spectrum
became a major problem. To resolve this the concept of cellular
communication was evolved. The cellular communication uses a basic unit
called cell. Each cell consists of small hexagonal area with a base station
located at the centre of the cell., which communicates with the user. To
accommodate multiple users , Time Division multiple Access(TDMA),
Code Division Multiple Access(CDMA) , Frequency Division Multiple
Access (FDMA) and their hybrids were proposed and had been in use.
 Multiple Access Schemes
Multiple access to a transmission medium is related to the channel
properties and modulation applied. The division of the frequency
spectrum assigned to the system in a certain number of sub bands
used by different users is called FDMA. The users share the same
spectrum but dividing time among themselves is known as TDMA.
Users generate signals that occupy the whole system band width
and time. However due to the application of specific signal
sequence uniquely characterizing each user, the receiver is able to
extract the signal of the selected user from sum of signals emitted
by different users. This approach is known as CDMA .
 Time Division Multiple Access
Time Division Access Method is a channel access method for shared
medium networks. It allows several users to share the same frequency
channel by dividing the signal into different time slots. The users
transmit in rapid succession, one after the other, each using his own
time slot. This allows multiple stations to share the same transmission
medium (e.g. radio frequency channel) while using only a part of its
channel capacity. TDMA is used in the digital 2G cellular systems
such as Global System for Mobile Communications (GSM), IS-136,
Personal Digital Cellular (PDC) and iDEN, and in the Digital
Enhanced Cordless Telecommunications (DECT) standard for portable
phones It is also used extensively in satellite systems, and combat-net
radio systems. For usage of Dynamic TDMA packet mode
communication, see below.
TDMA frame structure showing a data stream divided into
frames and those frames divided into time slots.
TDMA is a type of Time-division multiplexing, with the special point that instead of
having one transmitter connected to one receiver, there are multiple transmitters. In
the case of the uplink from a mobile phone to a base station this becomes
particularly difficult because the mobile phone can move around and vary the timing
advance required to make its transmission match the gap in transmission from its
peers.

TDMA is used along with FDMA by the Iridium and Thuraya satellite phone.

The ITU-T G.hn(International Telecommunication Union) standard, which provides

high-speed local area networking over existing home wiring (power lines, phone
lines and coaxial cables) is based on a TDMA scheme. In G.hn, a "master" device
allocates "Contention-Free Transmission Opportunities" (CFTXOP) to other "slave"
devices in the network. Only one device can use a CFTXOP at a time, thus avoiding
collisions. FlexRay protocol which is also a wired network used for Safety Critical
communication in modern cars, uses the TDMA method for data transmission
control.

In dynamic time division multiple access, a scheduling algorithm dynamically

reserves a variable number of time slots in each frame to variable bit-rate data
streams, based on the traffic demand of each data stream.
 Frequency Division Multiple Access
• Frequency Division Multiple Access or FDMA is a channel
access method used in multiple-access protocols as a
channelization protocol. FDMA gives users an individual
allocation of one or several frequency bands, or channels.
Multiple Access systems coordinate access between multiple
users. The users may also share access via different methods
such as TDMA, CDMA, or SDMA. These protocols are utilized
differently, at different levels of the theoretical OSI model.

• Disadvantage: Crosstalk which causes interference on the other

frequency and may disrupt the transmission.
 Features
• FDMA requires high-performing filters in the radio hardware, in contrast to TDMA
and CDMA.
• FDMA is not vulnerable to the timing problems that TDMA has. Since a
predetermined frequency band is available for the entire period of communication,
stream data (a continuous flow of data that may not be packetized) can easily be
used with FDMA.
• Each user transmits and receives at different frequencies as each user gets a unique
frequency slot
• It is important to distinguish between FDMA and frequency-division duplexing
(FDD). While FDMA allows multiple users simultaneous access to a certain
system, FDD refers to how the radio channel is shared between the uplink and
downlink (for instance, the traffic going back and forth between a mobile-phone
and a base-station). Furthermore, frequency-division multiplexing (FDM) should
not be confused with FDMA. The former is a physical layer technique that
combines and transmits low-bandwidth channels through a high-bandwidth
channel. FDMA, on the other hand, is an access method in the data link layer.
• FDMA also supports demand assignment in addition to fixed assignment. Demand
assignment allows all users apparently continuous access of the radio spectrum by
assigning carrier frequencies on a temporary basis using a statistical assignment
process.
 Code Division Multiple Access
• Code division multiple access (CDMA) is a channel access method
used by various radio communication technologies.
• One of the basic concepts in data communication is the idea of
allowing several transmitters to send information simultaneously over
a single communication channel. This allows several users to share a
band of frequencies (see bandwidth). This concept is called
multiplexing. CDMA employs spread-spectrum technology and a
special coding scheme (where each transmitter is assigned a code) to
allow multiple users to be multiplexed over the same physical
channel. By contrast, time division multiple access (TDMA) divides
access by time, while frequency-division multiple access (FDMA)
divides it by frequency. CDMA is a form of spread-spectrum
signaling, since the modulated coded signal has a much higher data
bandwidth than the data being communicated.
• One of the early applications for code division multiplexing is in GPS
CDMA is a spread spectrum multiple access technique. A spread spectrum
technique spreads the bandwidth of the data uniformly for the same
transmitted power. Spreading code is a pseudorandom code that has a narrow
Ambiguity function, unlike other narrow pulse codes. In CDMA a locally
generated code runs at a much higher rate than the data to be transmitted.
Data for transmission is simply logically XOR (exclusive OR) added with
the faster code.
The data signal with pulse duration of Tb is XOR added with the code signal
with pulse duration of Tc. (Note: bandwidth is proportional to 1/T where T =
bit time) Therefore, the bandwidth of the data signal is 1 / Tb and the
bandwidth of the spread spectrum signal is 1 / Tc. Since Tc is much smaller
than Tb, the bandwidth of the spread spectrum signal is much larger than the
bandwidth of the original signal. The ratio Tb / Tc is called spreading factor
or processing gain and determines to a certain extent the upper limit of the
total number of users supported simultaneously by a base station. The
following figure shows how spread spectrum signal is generated.
Each user in a CDMA system uses a different code to modulate
their signal. Choosing the codes used to modulate the signal is
very important in the performance of CDMA systems. The best
performance will occur when there is good separation between the
signal of a desired user and the signals of other users. The
separation of the signals is made by correlating the received signal
with the locally generated code of the desired user. If the signal
matches the desired user's code then the correlation function will
be high and the system can extract that signal.In general, CDMA
belongs to two basic categories: synchronous (orthogonal codes)
and asynchronous (pseudorandom codes).
 GSM
• GSM (Global System for Mobile Communications is the most popular standard
for mobile telephony systems in the world. The GSM Association, its promoting
industry trade organization of mobile phone carriers and manufacturers,
estimates that 80% of the global mobile market uses the standard. GSM is used
by over 1.5 billion people across more than 212 countries and territories.
• GSM differs from its predecessor technologies in that both signaling and speech
channels are digital, and thus GSM is considered a second generation (2G)
mobile phone system. This also facilitates the wide-spread implementation of
data communication applications into the system.
• The ubiquity of implementation of the GSM (Global System Market) standard
has been an advantage to both consumers, who may benefit from the ability to
roam and switch carriers without replacing phones, and also to network
operators, who can choose equipment from many GSM equipment vendors.
GSM also pioneered low-cost implementation of the short message service
(SMS), also called text messaging, which has since been supported on other
mobile phone standards as well. The standard includes a worldwide emergency
telephone number feature
 CELLULAR NETWORK
• GSM is a cellular network, which means that mobile phones
connect to it by searching for cells in the immediate vicinity. There
are five different cell sizes in a GSM network—macro, micro,
pico, femto and umbrella cells. The coverage area of each cell
varies according to the implementation environment. Macro cells
can be regarded as cells where the base station antenna is installed
on a mast or a building above average roof top level. Micro cells
are cells whose antenna height is under average roof top level; they
are typically used in urban areas. Pico cells are small cells whose
coverage diameter is a few dozen metres; they are mainly used
indoors. Femtocells are cells designed for use in residential or
small business environments and connect to the service provider’s
network via a broadband internet connection. Umbrella cells are
used to cover shadowed regions of smaller cells and fill in gaps in
coverage between those cells.
 Network structure

• The structure of a GSM network

• The network is structured into a number of discrete
sections:
• The Base Station Subsystem (the base station and their
controllers).
• the Network and Switching Subsystem (the part of the
network most similar to a fixed network). This is sometimes
also just called the core network.
• The GPRS Core Network (the optional part which allows
packet based Internet connections).
• The Operations support system (OSS) for maintenance of
the network..
SIM- SUBSCRIBER IDENTITY MODULE
One of the key features of GSM is the Subscriber Identity Module, commonly
known as SIM card. The SIM is a detachable smart card containing the user's
subscription information and phone book. This allows the user to retain his or her
information after switching handsets. Alternatively, the user can also change
operators while retaining the handset simply by changing the SIM. Some operators
will block this by allowing the phone to use only a single SIM, or only a SIM issued
by them; this practice is known as SIM locking and is illegal in some countries.
Phone locking
Sometimes mobile network operators restrict handsets that they sell for use with
their own network. This is called locking and is implemented by a software feature
of the phone.
In some territories (e.g., Bangladesh, Hong Kong, India, Malaysia, Pakistan,
Singapore) all phones are sold unlocked. In others (e.g., Belgium, Finland,
Germany, Singapore) it is unlawful for operators to offer any form of subsidy on a
phone's price.
 GSM SERVICE SECURITY
• GSM was designed with a moderate level of service security. The system was
designed to authenticate the subscriber using a pre-shared key and challenge-
response. Communications between the subscriber and the base station can be
encrypted. The development of UMTS introduces an optional Universal Subscriber
Identity Module (USIM), that uses a longer authentication key to give greater
security, as well as mutually authenticating the network and the user - whereas
GSM only authenticates the user to the network (and not vice versa). The security
model therefore offers confidentiality and authentication, but limited authorization
capabilities, and no non-repudiation.
• GSM uses several cryptographic algorithms for security. The A5/1 and A5/2 stream
ciphers are used for ensuring over-the-air voice privacy. A5/1 was developed first
and is a stronger algorithm used within Europe and the United States; A5/2 is
weaker and used in other countries. Serious weaknesses have been found in both
algorithms: it is possible to break A5/2 in real-time with a ciphertext-only attack,
and in February 2008, Pico Computing, Inc revealed its ability and plans to
commercialize FPGAs that allow A5/1 to be broken with a rainbow table attack.
The system supports multiple algorithms so operators may replace that cipher with
a stronger one.
 GPRS
• The General Packet Radio Service (GPRS) is a new non-voice value
added service that allows information to be sent and received across
a mobile telephone network. It supplements today's Circuit Switched
Data and Short Message Service. It is a step ahead to provide a
massive boost to mobile data usage and usefulness.
• GPRS offers a continuous connection to the Internet for mobile
phone and computer users. Experience has shown that most data
communication applications do not require continuous data transfer.
Users may need to be connected to a data communication network
(such as a LAN, WAN, the Internet, or a corporate Intranet), but that
does not mean they are sending and receiving data at all times. Data
transfer needs are not generally balanced. In the majority of cases,
users will tend to send out small messages but receive large
downloads. Therefore, most of the data transfer is in one direction.
 NETWORK FEATURES
• PACKET SWITCHING GPRS
involves overlaying a packet based air interface on the existing circuit switched
GSM network. This gives the user an option to use a packet-based data service.
With GPRS, the information is split into separate but related "packets" before
being transmitted and reassembled at the receiving end.
SPECTRUM EFFICIENCY
Efficient use of scarce radio resources means that large numbers of GPRS users
can potentially share the same bandwidth and be served from a single cell. The
actual number of users supported depends on the application being used and how
much data is being transferred. Because of the spectrum efficiency of GPRS,
there is less need to build in idle capacity that is only used in peak hours. GPRS
therefore lets network operators maximise the use of their network resources in a
dynamic and flexible way, along with user access to resources and revenues.
INTERNET AWARE
GPRS fully enables Mobile Internet functionality by allowing inter-working
between the existing Internet and the new GPRS network.
 METHOD OF OPERATION
• GPRS gives GSM subscribers access to data communication applications such as
e-mail, corporate networks, and the Internet using their mobile phones. The
GPRS service uses the existing GSM network and adds new packet-switching
network equipment. [2] GPRS employs packet switching, which means that the
GPRS mobile phone has no dedicated circuit assigned to it. Only when data is
transferred is a physical channel created. After the data has been sent, it can be
assigned to other users. This allows for the most efficient use of the network.
• When packet-switched data leaves the GPRS/GSM network, it is transferred to
TCP-IP networks such as the Internet or X.25.Thus, GPRS includes new
transmission and signaling procedures as well as new protocols for interworking
with the IP world and other standard packet networks. [2] Mobile phones
currently available do not work with the new GPRS technology. The industry’s
mobile phone vendors are working on new phones that will support both GSM
and packet switching. There is also a possibility in the future, that laptops and
PDA’s (Personal Digital Assistants) will have GPRS phone integrated in them.
Figure 6 is a diagram of the GPRS Network Architecture.
GPRS Network Architecture
APPLICATIONS :
1. CHAT
2. TEXTUAL AND VISUAL INFORMATION
3. EMAIL
4. REMOTE LAN ACCESS
5. FILE TRANSFER
6. HOME AUTOMATION

DRAWBACKS :
1. LIMITED CELL CAPACITY FOR ALL USERS
2. SPEEDS MUCH LOWER IN REALITY
 EDGE
• Enhanced Data rates for GSM Evolution (EDGE) (also known as
Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC), or
Enhanced Data rates for Global Evolution) is a digital mobile phone
technology that allows improved data transmission rates as a backward-
compatible extension of GSM. EDGE is considered a 3G radio
technology and is part of ITU's 3G definition. EDGE was deployed on
GSM networks beginning in 2003 — initially by Cingular (now AT&T)
in the United States.
• EDGE is standardized by 3GPP as part of the GSM family.
• Through the introduction of sophisticated methods of coding and
transmitting data, EDGE delivers higher bit-rates per radio channel,
resulting in a threefold increase in capacity and performance compared
with an ordinary GSM/GPRS connection.
• EDGE can be used for any packet switched application, such as an
Internet connection.
• EDGE/EGPRS is implemented as a bolt-on enhancement for 2.5G
GSM/GPRS networks, making it easier for existing GSM carriers to upgrade
to it. EDGE is a superset to GPRS and can function on any network with
GPRS deployed on it, provided the carrier implements the necessary
upgrade.
• EDGE/EGPRS is implemented as a bolt-on enhancement for 2.5G
GSM/GPRS networks, making it easier for existing GSM carriers to upgrade
to it. EDGE is a superset to GPRS and can function on any network with
GPRS deployed on it, provided the carrier implements the necessary
upgrade.
• EDGE requires no hardware or software changes to be made in GSM core
networks. EDGE-compatible transceiver units must be installed and the base
station subsystem needs to be upgraded to support EDGE. If the operator
already has this in place, which is often the case today, the network can be
upgraded to EDGE by activating an optional software feature. Today EDGE
is supported by all major chip vendors for both GSM and WCDMA/HSPA
GSM EDGE network architecture
SGSN:  GPRS Support Node - this forms a gateway to the services within the
network.
GGSN:  Gateway GPRS Support Node which forms the gateway to the outside
world.
PCU: Packet Control Unit which differentiates whether data is to be routed to the
packet switched or circuit switched networks.
A simplified view of the GSM EDGE network architecture can be seen in the
diagram below. From this it can be seen that it is very similar to the more basic
GSM network architecture, but with additional elements.
SGSN: The SGSN or Serving GPRS Support Node element of the GPRS
network provides a number of takes focussed on the IP elements of the overall
system. It provides a variety of services to the mobiles:
Packet routing and transfer
Mobility management
Authentication
Attach/detach
Logical link management
Charging data
GGSN
The GGSN, Gateway GPRS Support Node is one of the most important entities
within the GSM EDGE network architecture.
The GGSN organises the inter-working between the GPRS / EDGE network and
external packet switched networks to which the mobiles may be connected. These
may include both Internet and X.25 networks.
The GGSN can be considered to be a combination of a gateway, router and
firewall as it hides the internal network to the outside. In operation, when the
GGSN receives data addressed to a specific user, it checks if the user is active,
then forwarding the data. In the opposite direction, packet data from the mobile is
routed to the right destination network by the GGSN.

PCU
The PCU or Packet Control Unit is a hardware router that is added to the BSC. It
differentiates data destined for the standard GSM network (circuit switched data)
and data destined for the EDGE network (Packet Switched Data). The PCU itself
may be a separate physical entity, or more often these days it is incorporated into
the base station controller, BSC, thereby saving additional hardware costs.
 2G
• 2G (or 2-G) is short for second-generation wireless telephone
technology.Three primary benefits of 2G networks over their
predecessors were that phone conversations were digitally
encrypted; 2G systems were significantly more efficient on
the spectrum allowing for far greater mobile phone
penetration levels; and 2G introduced data services for
mobile, starting with SMS text messages. After 2G was
launched, the previous mobile telephone systems were
retrospectively dubbed 1G. While radio signals on 1G
networks are analog, and on 2G networks are digital, both
systems use digital signaling to connect the radio towers
(which listen to the handsets) to the rest of the telephone
system.
2G technologies can be divided into TDMA-based and CDMA-based standards
depending on the type of multiplexing used. The main 2G standards are:
GSM (TDMA-based), originally from Europe but used in almost all countries on
all six inhabited continents (Time Division Multiple Access). Today accounts for
over 80% of all subscribers around the world. Over 60 GSM operators are also
using CDMA2000 in the 450 MHz frequency band (CDMA450).
IS-95 aka cdmaOne (CDMA-based, commonly referred as simply CDMA in the
US), used in the Americas and parts of Asia. Today accounts for about 17% of all
subscribers globally. Over a dozen CDMA operators have migrated to GSM
including operators in Mexico, India, Australia and South Korea.
PDC (TDMA-based), used exclusively in Japan
iDEN (TDMA-based), proprietary network used by Nextel in the United States
and Telus Mobility in Canada
IS-136 aka D-AMPS (TDMA-based, commonly referred as simply 'TDMA' in
the US), was once prevalent in the Americas but most have migrated to GSM.
2G services are frequently referred as Personal Communications Service, or PCS,
in the United States.
2.5G services enable high-speed data transfer over upgraded existing 2G
networks. Beyond 2G, there's 3G, with higher data speeds, and even evolutions
beyond 3G, such as 4G.
Advantages
1. The lower power emissions helped address health concerns.
2. Going all-digital allowed for the introduction of digital data services,
such as SMS and email.
3. Greatly reduced fraud. With analog systems it was possible to have
two or more "cloned“
handsets that had the same phone number.
4. Enhanced privacy. A key digital advantage not often mentioned is that

digital cellular calls

are much harder to eavesdrop on by use of radio scanners. While the
security algorithms used
have proved not to be as secure as initially advertised, 2G phones are
immensely more private
than 1G phones, which have no protection against eavesdropping.
Disadvantages
1. The downsides of 2G systems, not often well publicized, are:
2. In less populous areas, the weaker digital signal may not be sufficient to reach

a cell tower. This tends to be a particular problem on 2G systems deployed on

higher frequencies, but is mostly not a problem on 2G systems deployed on
lower frequencies. National regulations differ greatly among countries which
dictate where 2G can be deployed.
3. Analog has a smooth decay curve, digital a jagged steppy one. This can be
both an advantage and a disadvantage. Under good conditions, digital will
sound better. Under slightly worse conditions, analog will experience static,
while digital has occasional dropouts. As conditions worsen, though, digital
will start to completely fail, by dropping calls or being unintelligible, while
analog slowly gets worse, generally holding a call longer and allowing at
least a few words to get through.
4. While digital calls tend to be free of static and background noise, the lossy
compression used by the codecs takes a toll; the range of sound that they
convey is reduced. You'll hear less of the tonality of someone's voice talking
on a digital cellphone, but you will hear it more clearly.
 3G
• International Mobile Telecommunications-2000 (IMT--2000),
better known as 3G or 3rd Generation, is a generation of standards
for mobile phones and mobile telecommunications services fulfilling
specifications by the International Telecommunication Union.
Application services include wide-area wireless voice telephone,
mobile Internet access, video calls and mobile TV, all in a mobile
environment. Compared to the older 2G and 2.5G standards, a 3G
system must allow simultaneous use of speech and data services, and
provide peak data rates of at least 200 kbit/s according to the IMT-
2000 specification. Recent 3G releases, often denoted 3.5G and
3.75G, also provide mobile broadband access of several Mbit/s to
laptop computers and smartphones.
The following standards are typically branded 3G:
the UMTS system, first offered in 2001, standardized by 3GPP, used primarily in Europe,
Japan, China (however with a different radio interface) and other regions predominated by
GSM 2G system infrastructure. The cell phones are typically UMTS and GSM hybrids.
Several radio interfaces are offered, sharing the same infrastructure:
The original and most widespread radio interface is called W-CDMA.
The TD-SCDMA radio interface, was commercialized in 2009 and is only offered in
China.
The latest UMTS release, HSPA+, can provide peak data rates up to 56 Mbit/s in the
downlink in theory (28 Mbit/s in existing services) and 22 Mbit/s in the uplink.
the CDMA2000 system, first offered in 2002, standardized by 3GPP2, used especially in
North America and South Korea, sharing infrastructure with the IS-95 2G standard. The
cell phones are typically CDMA2000 and IS-95 hybrids. The latest release EVDO Rev B
offers peak rates of 14.7 Mbit/s down streams.
The above systems and radio interfaces are based on kindred spread spectrum radio
transmission technology. While the GSM EDGE standard ("2.9G"), DECT cordless phones
and Mobile WiMAX standards formally also fulfill the IMT-2000 requirements and are
approved as 3G standards by ITU, these are typically not branded 3G, and are based on
completely different technologies.
(1) At present, we provide various semiconductors including CPUs for both
communication processing (digital base band) parts and parts that process
higher applications such as digital cameras, GPS, sound sources, and TV
tuners. In the future we will focus in particular on semiconductors for the latter,
and provide a variety of value-added products for mobile phones.
(2) 3G mobile will be using more LCD (Liquid Crystal Display) and multi-
panels. To drive these devices more smoothly, we will provide LCD
driver/controllers for color TFTs and large panels. Also, we have started
developing a technology to make the connection cable between the cards and
LCD screen thinner by making them serial cables.
(3) In order to perform the processing described above, a number of high
capacity memory types are required. At the same time, only a limited amount
of space is available inside the mobile phone and the physical memory size
must be kept as small as possible. To satisfy these contradictory requirements,
high-density memory and custom IC mounting are used. A package solution
will be provided that places everything into a single package using SIP (System
in Package) technology.

NEC Electronics will also provide various devices that can be used with
conventional second-generation mobile terminals. Please see the following
block diagram.
 Applications
• The bandwidth and location information available to 3G devices gives
rise to applications not previously available to mobile phone users.
Some of the applications are:
• Mobile TV – a provider redirects a TV channel directly to the
subscriber's phone where it can be watched.
• Video on demand – a provider sends a movie to the subscriber's
phone.
• Video conferencing – subscribers can see as well as talk to each other.
• Tele-medicine – a medical provider monitors or provides advice to the
potentially isolated subscriber.
• Location-based services – a provider sends localized weather or
traffic conditions to the phone, or the phone allows the subscriber to
find nearby businesses or friends.
 4G
• 4G refers to the fourth generation of cellular wireless
standards. It is a successor to 3G and 2G families of
standards. The nomenclature of the generations generally
refers to a change in the fundamental nature of the service,
non-backwards compatible transmission technology and new
frequency bands. The first was the move from 1981 analog
(1G) to digital (2G) transmission in 1992. This was followed,
in 2002, by 3G multi-media support, spread spectrum
transmission and at least 200 kbit/s, soon expected to be
followed by 4G, which refers to all-IP packet-switched
networks, mobile ultra-broadband (gigabit speed) access and
multi-carrier transmission.
 Objectives
• 4G is being developed to accommodate the quality of service (QoS) and rate
requirements set by further development of existing 3G applications like mobile
broadband access, Multimedia Messaging Service (MMS), video chat, mobile TV,
but also new services like HDTV. 4G may allow roaming with wireless local area
networks, and may interact with digital video broadcasting systems.
• The 4G working group has defined the following as objectives of the 4G wireless
communication standard:
• Flexible channel bandwidth, between 5 and 20 MHz, optionally up to 40 MHz.
• A nominal data rate of 100 Mbit/s while the client physically moves at high speeds
relative to the station, and 1 Gbit/s while client and station are in relatively fixed
positions as defined by the ITU-R
• A data rate of at least 100 Mbit/s between any two points in the world,
• Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75 bit/s/Hz in the
uplink (meaning that 1 Gbit/s in the downlink should be possible over less than
67 MHz bandwidth)
 IMPACT
• Communication is an integral part of life. Telephones have replaced
telegrams and letters. The ‘Mobile’ has completely revolutionized
the communication. It has opened up innovative applications that are
limited to one’s imagination. A person has connectivity to any one
any where in the world provided destination party is connected /
reachable through some tele-communication net work Some of the
areas where quality of life is expected to improve are
1. Research
2. Students
3. Intelligence Agencies
4. Air Line Staff
5. Electronics Bills
6. Sales Professional and Real Estate Agents
7. Remote Stock Broker