Gsm architecture

Gsm architecture

1. GSM A RCHITECTURE Asst.Prof. Rupali Lohar Dept. of Computer Science & Engineering B. R. Harne College Of Engineering & Technology,   Karav, Post Vangani (W Tal Ambernath , Mumbai, Maharashtra 421503

2. C ONTENTS GSM-introduction GSM Services Architecture Security in GSM Characteristics of GSM standard Advantages of GSM Future of GSM

3. 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 . digital technology supporting up to 14.4 to 64kbps (maximum) data rate Code Division Multiple Access (CDMA) system First internet at lower data rate

4. GSM: H ISTORY Developed by Group Spéciale Mobile (founded 1982) which was an initiative of CEPT ( Conference of European Post and Telecommunication ) Under ETSI, GSM is named as “ G lobal S ystem for M obile communication “ in 1989 Full set of specifications phase-I became available in 1990 Phase 2 of the GSM specifications occurs in 1995. Coverage is extended to rural areas

5. GSM IN W ORLD 37% 1% 4% 43% 4% 3% 3% (INDIA) Figures: March, 2005 3% 3% Arab World Asia Pacific Africa East Central Asia E u r op e Ru ss i a India North America South America

6. GSM IN I NDIA B ha r t i 27% BS N L 22% S p i ce 4% I D E A 13% H u t ch 19% A i r c e l 4% BPL 6% Figures: March 2005 Reliance 3% M T N L 2% B ha r t i BSNL H u t ch IDEA BPL A i r c e l S p i ce Reliance M T N L

7. The interfaces defined between each of these sub systems include: 'A' interface between NSS and BSS ' Abis ' interface between BSC and BTS (within the BSS) 'Um' air interface between the BSS and the MS

8. I n t e r f ac es V LR A MSC U m Abis B S C IS D N, TUP Section 1 – GSM Architecture Overview

9. Section 1 – GSM Architecture Overview

10. GSM S YSTEM A RCHITECTURE -I Mobile Station (MS) Mobile Equipment (ME) Subscriber Identity Module (SIM) Base Station Subsystem (BSS) Base Transceiver Station (BTS) Base Station Controller (BSC) Network Switching Subsystem(NSS) Mobile Switching Center (MSC) Home Location Register (HLR) Visitor Location Register (VLR) Authentication Center (AUC) Equipment Identity Register (EIR)

11. Mobile Equipment (ME) Portable, vehicle mounted, hand held device Uniquely iden t if i ed by an IMEI (Interna t ional Mob i le Equipment Identity) Voice and data transmission Monitoring power and signal quality of surrounding cells for optimum handover Power level : 0.8W – 20 W 160 character long SMS.

12. S UBSCRIBER IDENTITY M ODULE (SIM) Smart card contains the International Mobile Subscriber Identity ( IMSI ) Allows user to send and receive calls and receive other subscribed services Protected by a password or PIN Can be moved from phone to phone – contains key information to activate the phone

13. Base Station Subsystem (BSS) Base Station Subsystem is composed of two parts that communicate across the standardized Abis interface allowing operation between components made by different suppliers Base Transceiver Station ( BTS ) Base Station Controller ( BSC )

14. Base Transceiver Station ( BTS ) The purpose of the BTS is to: provide radio access to the mobile stations manage the radio access aspects of the system Communicates with Mobile station and BSC Radio Transmitter/Receiver (TRX) Signal processing and control equipment

15. Base Station Controller ( BSC ) Allocates a channel for the duration of a call Maintains the call: Monitors quality Controls the power transmitted by the BTS or MS generates a handover to another cell when required Manages Radio resources for BTS Handles call set up Handover for each MS It communicates with MSC and BTS

16. Network Switching Subsystem(NSS) The system contains the following functional units Mobile Switching Center (MSC) Home Location Register (HLR) Visitor Location Register (VLR) Authentication Center (AUC) Equipment Identity Register (EIR)

17. Mobile Switching Center (MSC) Heart of the network Manages communication between GSM and other networks Billing information and collection Mobility management Registration Location Updating Inter BSS and inter MSC call handoff

18. Home Location Register (HLR) Stores information about each subscriber that belongs to it MSC in permanent and temporary fashion. As soon as mobile subscriber leaves its current local area, the information in the HLR is updated. database contains prepaid / postpaid, roaming restrictions, supplementary services .

19. Visitor Location Register (VLR) Temporary database which updates whenever new MS enters its area, by HLR database Assigns a TMSI to each MS entering the VLR area which keeps on changing. Controls those mobiles roaming in its area Database contains Location Area, authentication key

20. Authentication Center (AUC) Contains the algorithms for authentication as well as the keys for encryption. Protects network operators from fraud. Situated in special protected part of the HLR.

21. Equipment Identity Register (EIR) Stores all devices identifications registered for this network. Database that is used to track handsets using the IMEI (International Mobile Equipment Identity) Prevents calls from stolen, unauthorised or defective mobile devices

22. S ECURITY 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

23. C HARACTERISTICS OF GSM Fully digital system using 900,1800 MHz frequency band. User/terminal authentication for fraud control. Full international roaming capability. Low speed data services (upto 9.6 Kb/s). Compatibility with ISDN. Support of Short Message Service (SMS).

24. 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. ADVANTAGES

25. GSM A PPLICATIONS Mobile telephony GSM technology is being mostly used for talking to family, friends and business colleagues. we use communication feature of Telephone landlines for internet, e-mail, data connectivity, remote monitoring, . computer to computer communication, security systems.

26. THANK YOU