The document provides an overview of the Global System for Mobile Communications (GSM), detailing its definition, history, architecture, advantages, disadvantages, and various applications. GSM is a digital cellular communication standard widely adopted globally, with over 3 billion subscribers and substantial market share. It emphasizes interoperability, security, and a range of telecommunication services, positioning itself as a significant component of modern mobile telephony.

1. Global
System
For
Mobile
Communication
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2. Discussion Points
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• What is GSM?
• Evolution of GSM
• Worldwide Deployment of GSM
• GSM vs. CDMA
• Generations of GSM
• GSM architecture
• Services of GSM
• Characteristics and features
• Advantages of GSM
• Disadvantages of GSM
• Applications of GSM
• Conclusion
• References
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What is GSM?
• The Global System for Mobile communications is a
digital cellular communications system. It was developed
in order to create a common European mobile telephone
standard but it has been rapidly accepted worldwide.
– Formerly it was “Groupe Spéciale Mobile” (founded
in 1982)
– now: Global System for Mobile Communication.
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4. Evolution of GSM
• 1982: Conference of European Post and
Telecommunications (CEPT) formed Group Speciale
Mobile called GSM.
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5. Worldwide Deployment
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• 930 networks in 222 countries and regions.
• More than 3 billion subscribers worldwide.
• More than 80% worldwide market share.
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6. GSM CDMA
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Stands for Global System for Mobile
communication
Code Division Multiple Access
Storage Type SIM (subscriber identity module)
Card
Internal Memory
Global market share 75% 25%
Dominance Dominant standard worldwide
except the U.S.
Dominant standard in the U.S
Data transfer GPRS/E/3G/4G/LTE EVDO/3G/4G/LTE
Network Every cell has a corresponding
network tower, which serves the
mobile phones in that cellular
area.
There is one physical channel and a
special code for every device in the
coverage network. Using this code,
the signal of the device is
multiplexed, and the same physical
channel is used to send the signal.
International roaming Most Accessible Less Accessible
Frequency band Multiple (850/900/1800/1900
MHz)
Single (850 MHz)
Network service SIM specific. User has option to
select handset of his choice.
Handset specific

7. Generations of GSM
• 1st generation:- Analog mobile technologies :- AMPS , TACS & NMT.
• 2nd generation:- digital mobile technologies :- GSM , CDMA
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• 2.5generation:- Enhancement of GSM:- GPRS
• 3rd generation:- Technologies coursed by ITU-IMT
• The following table lists the key events in the GSM evolution
• AMPS—Advanced Mobile Phone System
• TACS----Total Access Communication System.
• NMT----Nordic Mobile Telephones
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8. GSM Architecture
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• 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)
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9. Mobile Station (MS)
The Mobile Station is made up of two entities:
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1. Mobile Equipment (ME)
2. Subscriber Identity Module (SIM)
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10. Mobile Station (MS)
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Mobile Equipment
• Portable hand held device
• Uniquely identified by an IMEI Voice
and data transmission
• Monitoring power and signal quality of
surrounding cells for optimum
handover.
Subscriber Identity Module (SIM)
• Smart card contains IMSI
• Allows user to send and receive calls.
• 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
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11. Base Station Controller (BSC)
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Base Transceiver Station (BTS):
• Encodes,encrypts,multiplexes,modulat
es and feeds the RF signals to the
antenna.
• Frequency hopping
• Communicates with MS and BSC
• Consists of Transceivers (TRX) units
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
• Transco ding and rate adaptation
functionality
• Handover for each MS
• Radio Power control
• It communicates with MSC and BTS Prepared by :Avani Trambadiya

12. Network Switching Subsystem (NSS)
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• 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.
• 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
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13. Network Switching Subsystem (NSS)
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• 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
- Only one EIR per PLMN
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14. GSM Architecture
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15. GSM Operation from speech to radio wave
Speech Speech
Speech Channel 15
De-Burst De-Speech coding
13 Kbps
Channel Coding
22.8 Kbps
Interleaving
22.8 Kbps
Burst Formatting
33.6 Kbps
Ciphering
Radio
Interface
33.6 Kbps
Modulation Demodulation
270.83 Kbps
Speech decoding
Channel decoding
De-interleaving
Burst Formatting
De-ciphering
Demodulation
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GSM Services
• Tele-services
• Bearer or Data Services
• Supplementary services
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Tele-services
• Telecommunication services that enable voice
communication via mobile phones.
• Offered services
- Mobile telephony
- Emergency calling
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Bearer Services
• 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
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19. Supplementary Services
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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
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20. Characteristics of GSM
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• Fully digital system.
• Security against fraud
• Enhance privacy
• Full international roaming capability.
• Support for new services.
• Compatibility with ISDN.
• Support of Short Message Service (SMS).
• Good subjective voice quality.
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21. Advantages of GSM
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• Better Quality of speech
• Data transmission is
supported
• New services offered due
to ISDN compatibility
• International Roaming
possible
• Large market
• Crisper, cleaner quieter
calls
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22. Disadvantages of GSM
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• Dropped and missed calls
• Less Efficiency
• Security Issues
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23. Applications of GSM
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• Mobile telephony
• GSM-R
• Telemetry System
- Fleet management
- Automatic meter
reading
- Toll Collection
- Remote control and
fault reporting of DG
sets
• Value Added Services
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Conclusion
• The mobile telephony industry rapidly growing and
that has become backbone for business success and
efficiency and a part of modern lifestyles all over the
world.
• In this session I have tried to give and over view of the
GSM system. I hope that I gave the general flavor of
GSM and the philosophy behind its design.
• The GSM is standard that insures interoperability
without stifling competition and innovation among the
suppliers to the benefit of the public both in terms of
cost and service quality.
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References
• www.slideshare.com
• www.wikipidia.com
• www.seminarsonly.com
• www.gsmarena.com
• www.gsm-architecture.blogspot.com
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