INTRODUCTION TO CELLULAR TECHNOLOGY

GSM-GLOBAL SYSTEM FOR MOBILE COMMUNICATION

RAHUL GUPTA

Computer Engineering M.N.I.T Jaipur

2

TRAINING CARRIED AT

Computer Engineering M.N.I.T Jaipur

3

MOBILTY THE MAGIC WORD

IN THIS DAY & AGE ,MANY FOLKS NEED TO BE ACCESSIBLE EVERYWHERE ,WHETHER THEY’RE AT WORK OR PLAY,IN THE OFFICE OR AT HOME .

•WHAT IS NEEDED FOR MEETING THIS DEMAND?

Computer Engineering M.N.I.T Jaipur

4

GSM: GLOBAL SYSTEM FOR MOBILE COMMUNICATION

DEFINITIONGlobal system for mobile communication (GSM) is a globally accepted standard for digital cellular communication .GSM is the name of a standardization group established in 1982 to create a common European mobile telephone standard that would formulate specifications for a pan-European mobile cellular radio system operating at 900 MHz .it is estimated that many countries outside of Europe will join the GSM partnership.

Computer Engineering M.N.I.T Jaipur

5

EVOLUTION OF MOBILE TELEPHONE SYSTEMS

CELLULAR SUBSCRIBER GROWTH WORLDWIDE

0

20

40

60

80

100

1991 1993 1995 2005

YEAR

MILLIONS OF SUBSCRIBER

Series1

Computer Engineering M.N.I.T Jaipur

6

YEAR MOBILE SYSTEM1981 Nordic mobile telephone

1983 American mobile telephone system

1985 Total access communication system

1986 Nordic mobile technology

1991 American digital cellular

1991 GSM

1992 Digital cellular system

1994 Personal digital cellular

1995 PCS-1900

1995 CDMA

1996 PCS-United States

2003 GPRS

Computer Engineering M.N.I.T Jaipur

7

GSM-NETWORK ARCHITECTURE

Mobile station

Computer Engineering M.N.I.T Jaipur

8

Mobile station

Handset /mobile/portable terminal/mobile equipment

Includes– Subscriber identification module (SIM)

– IMSI

(INTERNATIONAL MOBILE SUBSCRIBER IDENTITY)

– MSISDN

– International mobile equipment identity (IMEI)

Computer Engineering M.N.I.T Jaipur

9

Base station subsystem(BSS)

Includes– Base transceiver station(BTS)

– Connect mobile to cellular network

– Channel coding\decoding

– Encryption\decryption

– Radio transmitters\receivers

– antennas

– Base station controller(BSC)– Group of BTS’s are connected to a BSC

– Call maintenance

– Report every 480 ms by MS

Computer Engineering M.N.I.T Jaipur

10

Network & switching subsystem(SS)

Includes– Mobile switching center(MSC)

– Act like a fixed exchange

– Provide all functionality for mobile subscriber

– Registration

– Location updating

– Handovers\call routing

– GMSC

– Home location register(HLR)– IMSI

– MSISDN

– Current VLR address

Computer Engineering M.N.I.T Jaipur

11

- Visitor location register(VLR)– Current location of the mobile station

– Connected to one MSC

– Integrated into MSC’s hardware

– Authentication center(AuC)– Hold secret key

– Located close to each HLR

– Equipment identity register(EIR)– List of valid mobile station(IMEI)

– Three databases

– White list

– Black list

– Grey list

Computer Engineering M.N.I.T Jaipur

12

INTERFACES & PROTOCOLS

OSI layer structurePHYSICAL LAYER

– Enable physical transmission– Assessment of channel quality

DATA LINK LAYER– Multiplexing of the signal channels– Error detection– Flow control– Routing

NETWORK LAYER– Connection management– Management of location data– Subscriber identification

Computer Engineering M.N.I.T Jaipur

13

OSI ARCHITECTURE

PSTNPSPDNISDN

MS BTS BSC MSC

Um Abis A

Computer Engineering M.N.I.T Jaipur

14

The air interface Um

ITU (international telecommunication union) has allocated

following bands:

GSM 900:

uplink : 890-915 MHz

downlink:935-960 MHz

GSM 1800:

uplink : 1710-1785 MHz

downlink:1805-1880 MHz

* TDMA\FDMA scheme

* BURST – fundamental unit in the TDMA scheme

Computer Engineering M.N.I.T Jaipur

15

Protocols on the air interfaceLayer 1: Um interface

Layer 2: LAP-Dm protocol

Layer 3: Radio Resource Management (RR): to establish and release stable connection between mobile stations (MS) and MSC for the duration of a call     

    -Cell selection,              -Handover,              -Monitoring and forwarding of radio connections,              -Introduction of encryption,             Mobility management (MM) handles control functions for mobility            -Authentication,             -Assignment of TMSI,              -Management of subscriber location.    Connection management (CM)set up, maintain calls-  connections            

-Call control (CC): Manages call connections,              -Supplementary service support (SS): special services,               -Short message service support (SMS): Transfers brief texts.

Computer Engineering M.N.I.T Jaipur

16

System features

Cell architectureHandoverSecurity

– Users identity& authentication– Mobile security

Computer Engineering M.N.I.T Jaipur

17

CELL ARCHITECTURE

Computer Engineering M.N.I.T Jaipur

18

Handover

Computer Engineering M.N.I.T Jaipur

19

User identity & authentication

Computer Engineering M.N.I.T Jaipur

20

GSM-subscriber services

Computer Engineering M.N.I.T Jaipur

21

GSM –SUBSCRIBER SERVICES

Telephony services(teleservices)

These are mainly voice services that provide subscriber with the complete capability(including necessary terminal equipment) to communicate with other subscribers.

Data services(bearer services)

These provides the capacity necessary to transmit appropriate data signals between two access points creating an interface to the network .

Subscriber services

-Facsimile group

-SMS-Cell broadcast-Voice mail-Fax mail

Computer Engineering M.N.I.T Jaipur

22

Supplementry services

-Call forwarding

-Baring of outgoing calls

-Baring of incoming calls

-Call hold

-Call waiting

-Calling line identification presentation

Computer Engineering M.N.I.T Jaipur

23

GSM V/S CDMA

PARAMETERS GSM CDMATECHNOLOGY USED

FDMA\ TDMA SPREAD SPECTRUM TECHNOLOGY

HANDOVER HARD

BREAK BEFORE MAKE

SOFT

MAKE BEFORE BREAK

DATA RATE 56 kbps 64-140kbps

INTERNATIONAL ROAMING

456 MILLION USERS

127 MILLION USERS

Computer Engineering M.N.I.T Jaipur

24

THE ONLY WAY TO KNOW AN ANSWER IS TO QUESTION FIRST

?

Computer Engineering M.N.I.T Jaipur

25

THANK YOU