Presentation on GSM
Network
What is GSM ?
Global System for Mobile (GSM) is a
second generation cellular standard
developed to cater voice services and
data delivery using digital modulation
GSM: History
• Developed by Group Spéciale Mobile (founded 1982) which was an
initiative of CEPT.
• Full set of specifications phase-I became available in 1990
• Under ETSI, GSM is named as “ Global System for Mobile
communication “
• Today many providers all over the world use GSM (more than 135
countries in Asia, Africa, Europe, Australia, America)
• More than 1300 million subscribers in world and 45 million subscriber in
India.
GSM in World
Figures: March, 2005 Arab World
3% Asia Pacific
3%
3% Africa
3% (INDIA)
East Central Asia
4% 37% Europe
Russia
43% 4% India
1%
North America
South America
GSM IN ALL OVER THE WORLD
GSM Services
Tele-services
Beareror Data Services
Supplementary services
Tele Services
• Telecommunication services that enable voice communication
via mobile phones
• Offered services
- Mobile telephony
- Emergency calling
Bearer Services
Include various data services for information transfer
between GSM and other networks like PSTN, ISDN etc at
rates from 300 to 9600 bps
Short Message Service (SMS)
–up to 160 character alphanumeric data transmission
to/from the mobile terminal
Unified Messaging Services(UMS)
Group 3 fax
Voice mailbox
Electronic mail
System Architecture
Mobile Station (MS)
The Mobile Station is made up of two entities:
1. Mobile Equipment (ME)
2. Subscriber Identity Module (SIM)
System Architecture
Network Switching Subsystem(NSS)
Mobile Switching Center (MSC)
Heart of the network
Manages communication between GSM and other networks
Call setup function and basic switching
Call routing
Billing information and collection
Mobility management
- Registration
- Location Updating
- Inter BSS and inter MSC call handoff
MSC does gateway function while its customer roams to other
network by using HLR/VLR.
GSM Specifications-1
RF Spectrum
GSM 900
Mobile to BTS (uplink): 890-915 Mhz
BTS to Mobile(downlink):935-960 Mhz
Bandwidth : 2* 25 Mhz
GSM 1800
Mobile to BTS (uplink): 1710-1785 Mhz
BTS to Mobile(downlink) 1805-1880 Mhz
Bandwidth : 2* 75 Mhz
GSM Specification-II
CarrierSeparation : 200 Khz
Duplex Distance : 45 Mhz
No. of RF carriers : 124
Access Method : TDMA/FDMA
Modulation Method : GMSK
Modulation data rate : 270.833 Kbps
GSM Operation
Speech Speech
Speech coding Speech decoding
13 Kbps
Channel Coding Channel decoding
22.8 Kbps
Interleaving De-interleaving
22.8 Kbps
Burst Formatting Burst Formatting
33.6 Kbps
Ciphering De-ciphering
33.6 Kbps
Radio Interface
Modulation
270.83 Kbps
Demodulation
Security in GSM
On air interface, GSM uses encryption and TMSI instead
of IMSI.
SIM is provided 4-8 digit PIN to validate the ownership of
SIM
3 algorithms are specified :
- A3 algorithm for authentication
- A5 algorithm for encryption
- A8 algorithm for key generation
Characteristics of GSM Standard
Fully digital system using 900,1800 MHz frequency band.
TDMA over radio carriers(200 KHz carrier spacing.
8 full rate or 16 half rate TDMA channels per carrier.
User/terminal authentication for fraud control.
Encryption of speech and data transmission over the radio
path.
Full international roaming capability.
Low speed data services (upto 9.6 Kb/s).
Compatibility with ISDN.
Support of Short Message Service (SMS).
Advantages of GSM over Analog system
Capacity increases
Reduced RF transmission power and longer battery life.
International roaming capability.
Better security against fraud (through terminal validation
and user authentication).
Encryption capability for information security and privacy.
Compatibility with ISDN,leading to wider range of
services
GSM Applications
Mobile telephony
GSM-R
Telemetry System
- Fleet management
- Automatic meter reading
- Toll Collection
- Remote control and fault reporting of DG sets
Value Added Services
Future Of GSM
2nd Generation
GSM -9.6 Kbps (data rate)
2.5 Generation ( Future of GSM)
HSCSD (High Speed ckt Switched data)
Data rate : 76.8 Kbps (9.6 x 8 kbps)
GPRS (General Packet Radio service)
Data rate: 14.4 - 115.2 Kbps
EDGE (Enhanced data rate for GSM Evolution)
Data rate: 547.2 Kbps (max)
3 Generation
WCDMA(Wide band CDMA)
Data rate : 0.348 – 2.0 Mbps
Thank you!!!!!
