1. GSM-Global System for Mobile Communication
SEMINAR ON
GSM-Global System for Mobile Communication
Presented by:- Pratibha ECE Vth sem

2. 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

3. 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.

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

5. Bearer Services Unified Messaging Services(UMS)
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

6. Supplementary Services
Call related services :
Call Waiting- Notification of an incoming call while on the handset
Call Hold- Put a caller on hold to take another call
Call Barring- All calls, outgoing calls, or incoming calls
Call Forwarding- Calls can be sent to various numbers defined by the user
Multi Party Call Conferencing - Link multiple calls together
CLIP – Caller line identification presentation
CLIR – Caller line identification restriction
CUG – Closed user group

7. GSM Specifications-1 System Uplink Downlink
GSM MHz MHz
GSM MHz MHz
GSM MHz MHz
GSM is a typical 2nd generation system

8. Performance characteristics of GSM
Communication
Mobile, wireless communication; support for voice and data srvices
Total mobility
International access, chip-card enables use of access points of different providers
Worldwide connectivity
One number, the network handles localization

9. GSM System Architecture
OMC ( B T S
UM Interface
HLR
PSTN
ISDN B T S
MSC VLR
Data
Networks B T S
BSC
A Interface
A-bis interface
VLR
Air interface

10. GSM Applications 1.Mobile telephony 2.Telemetry System
- Fleet management
- Automatic meter reading
- Toll Collection
- Remote control and fault reporting of stolen sets
3.Value Added Services

11. Mobile Station (MS) A Typical Handset Consists of the following parts:
A microscopic microphone
A speaker
An LCD or plasma display
A mini keyboard
An Antenna
A battery
A Circuit board
SIM

12. Mobile station (MS)
MS is the radio mobile terminal carried by the subscriber
MS comprises of all user equipment and software needed for communication with GSM end-point of the radio interface (Um)
MS consists of
User independent HW and SW
SIM (Subscriber Identity Module)
MS can be identified by IMEI (Intl Mobile Equipment Identity)
MSs have transmit power of 2W and 1W

13. SIM Subscriber Identity Module (SIM)
Smart card contains the International Mobile Subscriber Identity (IMSI)
Allows user to send and receive calls and receive other subscribed services
Encoded network identification details
- Key Ki,Kc and A3,A5 and A8 algorithms
Protected by a password or PIN
Can be moved from phone to phone – contains key information to activate the phone

14. What is SIM capable of?
Display text from the SIM on the Mobile Equipment's display.
Set up a voice or data call to a number held in the SIM
Send an SMS message.
Play a tone in the Mobile's ear-piece or ringer

15. CONTINUED Establish an interaction with the user.
Provide local information from the ME to the SIM.
Allow help text to be displayed for the user if requested.
Encrypt data being sent via handset whenever needed.
SIM cards were perceived as Security modules for authentication of user with some extra memory

16. System Architecture Base Station Subsystem (BSS)
Base Transceiver Station (BTS):
Encodes,encrypts,multiplexes,modulates and feeds the RF signals to the antenna.
Frequency hopping
Communicates with Mobile station and BSC
Consists of Transceivers (TRX) units

17. Base Transceiver Station (BTS)
Comprises of all radio specific functions and components including antennas, amplifiers, signal processing (houses all transceivers)
If directed antennas are used, one BTS can cover several cells
Connected to MS via Um interface and to BSC via Abis interface
GSM cell can measure between 100m to 35 kms depending on environment

18. Some functions of BTS
Ability to manage Full Rate and Half Rate channels.
Supervision of Stationary Wave Report (SWR) on the antenna
Frequency Hopping
Antenna Diversity
Discontinuous Transmission (DTX) both in the Uplink and Downlink

19. Base Station Controller (BSC)
Governs the radio resources for one or more BTSs
Controlling connection between the BTSs and MSCs
Managing of network resources, administrating radio channels, signaling, frequency hopping anad handovers
Mapping of radio channels (Um) onto terrestrial channels (A interface).
Performs paging of MS
Functions of transforming the Full Rate (16 KBPS) or Half Rate (8 KBPS) radio channels into 64 KBPS channels

20. Handover
Cellular systems require handover procedures, as single cells do not cover the whole service area, but, e.g., only up to 35 km around each antenna . The smaller the cell size and the faster the movement of a mobile station through the cells (up to 250 km/h for GSM), the more handovers of ongoing calls are required. However, a handover should not cause a cut-off, also called call drop.
There are two basic reasons for a handover (about 40 have been identified in the standard):The mobile station moves out of the range of a BTS or a certain antenna of a BTS respectively. Thus, the received signal level becomes lower continuously until it falls underneath the minimal requirements for communication. Or the error rate may grow due to interference, the distance to the BTS may be too high (max. 35 km) etc. - all these effects may diminish the quality of the radio link and make radio transmission impossible in the near future.

21. Cellular systems require Handover procedures
Two basic reasons
MS moves out of the range of a BTS - Signals becoming weaker
Interference cause errors

22. What is CDMA? Code Division Multiple Access (CDMA)
Digital Wireless Technology
Pioneered and commercially developed by QUALCOMM.
CDMA was adopted by the Telecommunications Industry Association (TIA) in 1993.
Commercially introduced in 1995

23. May 2001 there were 35 million subscribers on cdmaOne systems worldwide. 
As of Dec 2002,There were 127 million CDMA users worldwide.
Fastest-growing wireless technologies
Provides greater total capacity than other technologies
Choice new 3G systems

24. The original CDMA(IS 95) is now known as CDMAOne. 
We now have cdma2000 and its variants like 1x EV, 1xEV-DO, and 3x.
The refer to variants of usage of a
1x uses a 1.25Mhz channel.
3X uses a 3.75 Mhz channel

25. Advantages of CDMA
Huge Bandwidth
Voice clarity
Less call drops (almost zero) during the peak period
Efficient power control methods (even in the handsets)
More security

26. THANKS