2. Content-
Introduction
History of GSM System
Specification of GSM
Channel allocation in India
GSM frequencies
Cellular system Generation
Service provider in India
Frequency Reuse
Cell
3. HISTORY OF WIRELESS COMMUNICATION
• 1982 CEPT start to develop cell structure
• 1986 Basic GSM radio tarnsmission technics
chosen
• 1988 The Telecommunication Standarts Instute
define GSM
• 1989 Explanation is finished for GSM Generation 1
• 1991 First call in GSM
• 1992 First GSM Network in the world
• 1993 GSM Network is reached 32
• 1994 First GSM Network in Africa,
4. 1992 First GSM Network in the world
1993 GSM Network is reached 32
1994 First GSM Network in Africa,
1995 GSM Network is reached 117
1998 120 Million User on the World
1999 First GPRS
1998 480 Million User on the World
2003 863 Million User on the World
2004 3G World Congress
2007 2.4 Billion user on the world
5. Cellular systems generations
1G (first generation) – voice-oriented systems
based on analog technology; ex.: Advanced
Mobile Phone Systems (AMPS) and cordless
systems
2G (second generation) - voice-oriented
systems based on digital technology; more
efficient and used less spectrum than 1G; ex.:
Global System for Mobile (GSM) and US Time
Division Multiple Access (US-TDMA)
6. 3G (third generation) – high-speed voice-
oriented systems integrated with data services;
ex.: General Packet Radio Service (GPRS),
Code Division Multiple Access (CDMA)
4G (fourth generation) – still experimental, not
deployed yet; based on Internet protocol
networks and will provide voice, data and
multimedia service to subscribers
7. GSM - Specifications
Original specifications for the GSM system:
Good subjective voice quality
Low terminal and service cost
Support for international roaming
Support for handheld terminals
Support for new services
Spectrum efficient
Compatible with ISDN
8. Cellular Network Generations
It is useful to think of cellular
Network/telephony in terms of generations:
0G: Briefcase-size mobile radio telephones
1G: Analog cellular telephony
2G: Digital cellular telephony
3G: High-speed digital cellular telephony
(including video telephony)
4G: IP-based “anytime, anywhere” voice,
data, and multimedia telephony at faster
data rates than 3G
15. Frequency reuse
is a method used by service providers to
improve the efficiency of a cellular network
and to serve millions of subscribers using a
limited radio spectrum
is based on the fact that after a distance a
radio wave gets attenuated and the signal
falls bellow a point where it can no longer be
used or cause any interference
a transmitter transmitting in a specific
frequency range will have only a limited
coverage area
16. 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
17. Clusters
A cluster is a group of cells
No channels are reused within a cluster
A seven Cell Cluster
20. 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)
21. Mobile Station (MS)
Mobile Equipment
Portable,vehicle mounted, hand held device
Uniquely identified by an IMEI
(International Mobile 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.
22. 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
23. 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
1. Base Transceiver Station (BTS)
2. Base Station Controller (BSC)
24. 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
25. Base Station Subsystem (BSS)
Base Station Controller (BSC)
Manages Radio resources for BTS
Assigns Frequency and time slots for all
MS’s in its area
Handles call set up
Transcoding and rate adaptation
functionality
Handover for each MS
Radio Power control
26. Network Switching Subsystem(NSS)
Mobile Switching Center (MSC)
Heart of the network
Manages communication between GSM and
other networks
Call setup function and basic switching
Call routing
Billing information and collection
Mobility management
- Registration
- Location Updating
27. Network Switching Subsystem
Home Location Registers (HLR)
- permanent database about mobile
subscribers in a large service
area(generally one per GSM network
operator)
- database contains
IMSI,MSISDN,prepaid/postpaid,roaming
restrictions,supplementary services.
28. Visitor Location Registers (VLR)
- Temporary database which updates
whenever new MS enters its area, by
HLR database
- Controls those mobiles roaming in its
area
- Reduces number of queries to HLR
- Database contains
IMSI,TMSI,MSISDN,MSRN,Location
Area,authentication key
29. Authentication Center (AUC)
- Protects against intruders in air
interface
- Maintains authentication keys and
algorithms and provides security triplets
( RAND,SRES,Kc)
- Generally associated with HLR
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
30. Handovers
Between 1 and 2 –
Inter BTS / Intra
BSC
Between 1 and 3 –
Inter BSC/ Intra
MSC
Between 1 and 4 –
Inter MSC
