GSM Cellular

Slide 1: 

GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS Presenter : Abhishek Singh Chauhan, I.T. 4 th year

DEFINITION: 

DEFINITION Derived from Groupe Spécial Mobile Digital Cellular Telephone Technology Based on TDMA & FDMA Operates on 900 MHz In India Operates on 1800 MHz In Europe Operates on 1900 MHz In USA

HISTORY: 

HISTORY • Developed by Group Spéciale Mobile (founded in1982) which was an initiative of CEPT ( Conference of European Post and Telecommunication ) • Aim : to replace the incompatible analog system • Presently the responsibility of GSM standardization resides with special mobile group under ETSI ( European telecommunication Standards Institute ) Full set of specifications phase-I became available in 1990 • Under ETSI, GSM is named as “ G lobal S ystem for M obile 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 India Group Company wise % market share (Subscribers) as of September 2011 : 

GSM in India Group Company wise % market share (Subscribers) as of September 2011

Frequency multiplex: 

Frequency multiplex Separation of the whole spectrum into smaller frequency bands A channel gets a certain band of the spectrum for the whole time Advantages: no dynamic coordination necessary works also for analog signals Disadvantages: waste of bandwidth if the traffic is distributed unevenly inflexible guard spaces

Time multiplex: 

Time multiplex A channel gets the whole spectrum for a certain amount of time Advantages: only one carrier in the medium at any time throughput high even for many users Disadvantages: precise synchronization necessary

OPERATION OF CELLULAR SYSTEMS : 

OPERATION OF CELLULAR SYSTEMS Mobile unit initialization Mobile originated call Network originated call Call accepted Call termination Call drop Handoff procedure

GSM ARCHITECTURE: 

GSM ARCHITECTURE Mobile Station [MS] Base Station Subsystem [BSS] Network and switching subsystem [NSS] Operation support subsystem

MOBILE STATION: 

MOBILE STATION It includes- Subscriber identity module [SIM] Mobile equipment [ME] A SIM for Airtel Mobility (India)

BASE STATION SUBSYSTEM: 

BASE STATION SUBSYSTEM It consists of- Base transceiver station Base station controller Transcoder rate adaption unit OSS MS BSS NSS

NETWORK AND SWITCHING SUBSTATION: 

NETWORK AND SWITCHING SUBSTATION NSS management consists of- Mobile service switching center InterWorking function [IWF] Gateway MSC(Mobile Switching Center)

STRUCTURE OF GSM NETWORK: 

STRUCTURE OF GSM NETWORK

TRANSMISSION: 

TRANSMISSION It is divided into- Speech It uses: Regular pulse excitation [RPE] Linear prediction coding [LPE] Data service Modulation

GSM CHANNELS AND CHANNEL MODES: 

GSM CHANNELS AND CHANNEL MODES Physical channels TCH/F TCH/H TCH/8 Logical channels Common channels Downlink channels Uplink channels Signaling channels

GSM Specifications: 

GSM Specifications 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 : CURRENT GENERATION: 

GSM : CURRENT GENERATION 3G is the current GSM generation Based on the International Telecommunication Union (ITU)standards 3G uses .5 MHz channel carrier Supports greater numbers of voice and data customers at lower cost

GSM AND CDMA : A COMPARISION: 

GSM AND CDMA : A COMPARISION A GSM (TDMA+FDMA) mobile has a SIM card, which provides more functionality CDMA high communication security high carrier efficiency smaller phones, low power requirement Talk range GSM : 35 km CDMA : 110 km

THANK YOU !!!!: 

THANK YOU !!!!