GSM (GLOBAL SYSTEM FOR MOBILE COMMUNICATION)

1. GSM (GLOBAL SYSTEM FOR MOBILE COMMUNICATION) IP PROJECT WORK III Term SESSION – 2013 -14 Submitted to :-> MR. Ajmer Submitted by :-> HIMANI , POOJA (11 A)

2. It all started like this • First telephone (photophone) – Alexander Bell, 1880 • The first car mounted radio telephone – 1921

3. But what’s cellular? MSC BS PSTN HLR, VLR, AC, EIR

4. 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

5. GSM: History • Developed by Group Spéciale Mobile (founded 1982) 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 “ 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.

6. Tele Services • Telecommunication services that enable voice communication via mobile phones • Offered services - Mobile telephony - Emergency calling

7. GSM Overview

8. 1st Generation • Start to use in 1989 • Call forwarding • All calls • No answer • Engaged • Unreachable • Outgoing calls barring • Incoming calls barring • Global roaming

9. 2nd Generation • Finished process in 1995 • SMS(Short Message Services) • Multi Party Calling • Call holding • Call waiting • Mobile data service • Mobile fax service • Call line identity • Advice of charging • Cell broadcast

10. 2+ Generation • Start to use in 1998 • Services developed • DECT and GSM • VPN(Virtual Private Network) • Packet Radio • SIM development • Enjoyable services

11. GSM in World

12. GSM in India

13. GSM System Architecture PSTN ISDN PDN BSC MS BTS MSC GMSC BTS BSC VLR MS EIR BTS AUC MS HLR

14. MS sends dialled number to BSS BSS sends dialled number to MSC 3,4 MSC checks VLR if MS is allowed the requested service.If so,MSC asks BSS to allocate resources for call. MSC routes the call to GMSC GMSC routes the call to local exchange of called user 7, 8, 9,10 Answer back(ring back) tone is routed from called user to MS via GMSC,MSC,BSS Outgoing Call

15. Calling a GSM subscribers Forwarding call to GSMC Signal Setup to HLR 5. Request MSRN from VLR Forward responsible MSC to GMSC Forward Call to current MSC 9. Get current status of MS 11. Paging of MS 13. MS answers 15. Security checks 17. Set up connection Incoming Call

16. Between 1 and 2 – Inter BTS / Intra BSC Between 1 and 3 – Inter BSC/ Intra MSC Between 1 and 4 – Inter MSC Handovers

17. Authentication in GSM

18. Key generation and Encryption

19. Mobile RadioCellular Mobile Communications

20. Mobile Comms. Principles • Mobile uses a separate, temporary radio channel to talk to the cell site • Cell site talks to many mobiles at once, using one channel per mobile • Channels use a pair of frequencies for communication • The forward link for transmitting from the cell site • The reverse link for the cell site to receive calls from the users

21. Mobile Comms. Principles • Radio energy dissipates over distance, so mobiles must stay near the base station to maintain communications • Basic structure of mobile networks includes telephone systems and radio services

22. Mobile Comms. Principles • Where mobile radio service operates in a closed network and has no access to the telephone system, mobile telephone service allows interconnection to the telephone network

23. Mobile Comms. Principles • Radio energy dissipates over distance, so mobiles must stay near the base station to maintain communications • basic structure of mobile networks includes telephone systems and radio services

24. Mobile Systems Using Cells • The cellular concept employs variable low-power levels • cells are sized according to the subscriber density and demand in a given area • Cells can be added to accommodate population growth

25. Cellular System Architecture • In modern cellular telephony, rural and urban regions are divided into areas according to specific provisioning guidelines • Deployment parameters, such as amount of cell-splitting and cell sizes, are determined by engineers experienced in cellular system architecture

26. Cells • A cell is the basic geographic unit of a cellular system • The term cellular comes from the honeycomb shape of the areas into which a coverage region is divided • Cells are base stations transmitting over small geographic areas that are represented as hexagons • Size varies depending on the landscape

27. Speech Speech Speechdecoding Speech coding 13 Kbps Channel Coding Channeldecoding 22.8 Kbps Interleaving De-interleaving 22.8 Kbps BurstFormatting Burst Formatting 33.6 Kbps Ciphering De-ciphering 33.6 Kbps Radio Interface Modulation Demodulation 270.83 Kbps GSM Operation

28. GSM-Frame Structure

29. OPEN INTERFACES OF GSM • Network Switching Subsystem(NSS) • Base Station Subsystem(BSS) • Network Management Subsystem(NMS) or Operation and Support Subsystem(OSS) • They connect with Air,A,O&M interfaces

30. PROCEDURE OF CALL SET UP FROM MOBİLE USER

31. SIGNALS AND PROTOCOLS • STANDART MESSAGES • SENDER WANTS TO SERVICE • OPERATOR ASK THAT YOU WANTS TO TALK ,BUT WHICH USER • OPERATOR CONNECT TO RECEIVER • WHEN THE RECEIVER REPLIES TO CALL ,THE CALL STARTS • WHEN THE RECEIVER OR SENDER CLOSE THE PHONE , THE OPERATOR FINISH CONNECTION TO EACH OTHER

32. PROCEDURE OF SIGNALS

33. COMMON CHANNEL SIGNALLING SYSTEM • MTP(MASSAGE TRANSFER PART) • TUP(TELEPHONE USER PART) • SSCP(SIGNALLING CONNECTION AND CONTROL PART)