GSM (GLOBAL SYSTEM FOR
MOBILE COMMUNICATION)
IP PROJECT WORK
III Term
SESSION – 2013 -14
Submitted to :->
MR. Ajmer
Submitted by :->
HIMANI , POOJA (11 A)
It all started like this
• First telephone (photophone) – Alexander
Bell, 1880
• The first car mounted radio
telephone – 1921
But what’s cellular?
MSC
BS
PSTN
HLR, VLR,
AC, EIR
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
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.
Tele Services
Telecommunication services that
enable voice communication
•
via mobile phones
• Offered services
- Mobile telephony
- Emergency calling
GSM Overview
1st Generation
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Start to use in 1989
Call forwarding
All calls
No answer
Engaged
Unreachable
Outgoing calls barring
Incoming calls barring
Global roaming
2nd Generation
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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
2+
Generation
• Start to use in 1998
• Services developed
• DECT and GSM
• VPN(Virtual Private Network)
• Packet Radio
• SIM development
• Enjoyable services
GSM in World
3%
Figures: March, 2005
Arab World
3%
Asia Pacific
3%
3% (INDIA)
Africa
East Central Asia
4%
37%
Europe
Russia
43%
1%
4%
India
North America
South America
GSM in India
Figures: March 2005
Aircel
4%
Reliance
3%
MTNL
Spice
2%
4%
BPL
6%
Bharti
Bharti
27%
BSNL
Hutch
IDEA
BPL
IDEA
13%
Aircel
Hutch
19%
BSNL
22%
Spice
Reliance
MTNL
GSM System Architecture
PSTN
ISDN
PDN
BSC
MS
BTS
MSC
GMSC
BTS
BSC
VLR
MS
EIR
BTS
AUC
MS
HLR
Outgoing Call
1. MS sends dialled number to
BSS
2. BSS sends dialled number to
MSC
3,4
MSC checks VLR if MS is
allowed the requested service.I
so,MSC asks BSS to allocate
resources for call.
5 MSC routes the call to GMSC
6 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
Incoming Call
1. Calling a GSM
subscribers
2. Forwarding call to
GSMC
3. Signal Setup to HLR
4. 5. Request MSRN
from VLR
6. Forward responsible
MSC to GMSC
7. Forward Call to
current MSC
8. 9. Get current status
of MS
10.11. Paging of MS
12.13. MS answers
14.15. Security checks
16.17. Set up
Handovers
• Between 1 and 2 –
•
•
Inter BTS / Intra BSC
Between 1 and 3 –
Inter BSC/ Intra MSC
Between 1 and 4 –
Inter MSC
Authentication in GSM
Key generation and Encryption
Mobile Radio
Cellular Mobile
Communications
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
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
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
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
Mobile Systems Using Cells
• The cellular concept employs variable lowpower levels
– cells are sized according to the subscriber
density and demand in a given area
• Cells can be added to accommodate
population growth
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
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
GSM Operation
Speech
Speech
Speech decoding
Speech coding
13 Kbps
Channel Coding
Channel decoding
22.8 Kbps
Interleaving
De-interleaving
22.8 Kbps
Burst Formatting
Burst Formatting
33.6 Kbps
Ciphering
33.6 Kbps
Modulation
De-ciphering
Radio Interface
270.83 Kbps
Demodulation
GSM-Frame Structure
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
PROCEDURE OF CALL SET UP
FROM MOBİLE USER
SIGNALS AND PROTOCOLS
• STANDART MESSAGES
• SENDER WANTS TO SERVICE
• OPERATOR ASK THAT YOU WANTS TO TALK
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•
•
,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
PROCEDURE OF SIGNALS
COMMON CHANNEL SIGNALLING
SYSTEM
• MTP(MASSAGE TRANSFER PART)
• TUP(TELEPHONE USER PART)
• SSCP(SIGNALLING CONNECTION AND
CONTROL PART)