1. GSM – GLOBAL SYSTEM FOR
MOBILE COMMUNICATION
Muhammad Uzair Rasheed
2009-CPE-03
UCE&T BZU MULTAN

2. DISCUSSION TOPICS
Definition
System Architecture
Features (Basic and Advanced)
Advantages of GSM
Future – what’s next

3. Defnition
Global System for Mobile (GSM) is a
second generation cellular standard
developed to cater voice services and
data delivery using digital modulation

4. System Architecture
• Mobile Station (MS)
Mobile Equipment (ME)
Subscriber Identity Module (SIM)
• Base Station Subsystem (BBS)
Base Transceiver Station (BTS)
Base Station Controller (BSC)
• Network Subsystem
Mobile Switching Center (MSC)
Home Location Register (HLR)
Visitor Location Register (VLR)
Authentication Center (AUC)
Equipment Identity Register (EIR)

5. System Architecture
Mobile Station (MS)
The Mobile Station is made up of two entities:
1. Mobile Equipment (ME)
2. Subscriber Identity Module (SIM)

6. System Architecture
Mobile Station (MS) contd.
Mobile Equipment
• Produced by many different manufacturers
• Uniquely identified by an IMEI (International Mobile
Equipment Identity)
• Power level : 0.8W – 20 W

7. System Architecture
Mobile Station (MS) contd.
Subscriber Identity Module (SIM)
• Smart card containing 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

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

9. System Architecture
Base Station Subsystem (BSS) contd.
Base Transceiver Station (BTS)
• Houses the radio transceivers that define a cell
• Speech and data transmissions from the MS are recoded
• Requirements for BTS:
reliability
minimum costs

10. System Architecture
Base Station Subsystem (BSS) contd.
Base Station Controller (BSC)
• Manages Resources for BTS
• Handles call set up
• Location update
• Handover for each MS

11. System Architecture
Network Subsystem
Mobile Switching Center (MSC)
• Switch speech and data connections between:
Base Station Controllers
Mobile Switching Centers
GSM-networks
Other external networks
• Heart of the network
• Three main jobs:
1) connects calls from sender to receiver
2) collects details of the calls made and received
3) supervises operation of the rest of the network components

12. System Architecture
Network Subsystem contd.
• Home Location Registers (HLR)
- contains administrative information of each subscriber
- current location of the mobile
• Visitor Location Registers (VLR)
- contains selected administrative information from the HLR
- authenticates the user
- tracks which customers have the phone on and ready to
receive a call
- periodically updates the database on which phones are
turned on and ready to receive calls

13. System Architecture
Network Subsystem contd.
• Authentication Center (AUC)
- mainly used for security
- data storage location and functional part of the network
• Equipment Identity Register (EIR)
- Database that is used to track handsets using the IMEI
(International Mobile Equipment Identity)
- Made up of three sub-classes: The White List, The Black List
and the Gray List

14. System Architecture

15. Basic Features Provided by GSM
• 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

16. Advanced Features Provided by
GSM
• Calling Line ID
- incoming telephone number displayed
• Alternate Line Service
- one for personal calls
- one for business calls
• Closed User Group
- call by dialing last for numbers
• Advice of Charge
- tally of actual costs of phone calls
• Fax & Data
- Virtual Office / Professional Office
• Roaming
- services and features can follow customer from market to market

17. Future -- UMTS (Universal Mobile
Telephone System
• Reasons for innovations
- new service requirements
- availability of new radio bands
• User demands
- seamless Internet-Intranet access
- wide range of available services
- compact, lightweight and affordable terminals
- simple terminal operation
- open, understandable pricing structures for the whole
spectrum of available services

18. Advantages of GSM
• Crisper, cleaner quieter calls
• Security against fraud
• International roaming capability in over 100 countries
• Improved battery life
• Efficient network design for less expensive system expansion
• Efficient use of spectrum
• Advanced features such as short messaging and caller ID
• A wide variety of handsets and accessories
• High stability mobile fax and data at up to 9600 baud
• Ease of use with over the air activation, and all account information
is held in a smart card which can be moved from handset to
handset