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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. - PowerPoint PPT Presentation
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GSM (GLOBAL SYSTEM FOR GSM (GLOBAL SYSTEM FOR MOBILE COMMUNICATION)MOBILE COMMUNICATION)
Submitted to :->MR. Ajmer
Submitted by :->HIMANI , POOJA (11 A)
IP PROJECT WORKIII Term
SESSION – 2013 -14
It all started like thisIt all started like this
• First telephone (photophone) – First telephone (photophone) – Alexander Bell, 1880Alexander Bell, 1880
• The first car mounted radio The first car mounted radio
telephone – 1921telephone – 1921
But what’s cellular?But what’s cellular?
HLR, VLR, AC, EIR
MSC
PSTN
BS
What is GSM ?What is GSM ?
Global System for Mobile Global System for Mobile (GSM) is a second generation (GSM) is a second generation cellular standard developed to cellular standard developed to cater voice services and data cater voice services and data delivery using digital delivery using digital modulationmodulation
GSM: HistoryGSM: 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 Tele Services
• Telecommunication services that enable voice communication
via mobile phones
• Offered services
- Mobile telephony
- Emergency calling
GSM OverviewGSM Overview
1st Generation1st Generation
• Start to use in 1989• Call forwarding• All calls• No answer• Engaged• Unreachable• Outgoing calls barring• Incoming calls barring• Global roaming
2nd Generation2nd Generation
• 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 chargingAdvice of charging• Cell broadcastCell broadcast
2+ Generation
• Start to use in 1998Start to use in 1998
• Services developedServices developed
• DECT and GSMDECT and GSM
• VPN(Virtual Private Network)VPN(Virtual Private Network)
• Packet RadioPacket Radio
• SIM developmentSIM development
• Enjoyable servicesEnjoyable services
GSM in WorldGSM in World
Figures: March, 2005
37%
1%4%43%
4%
3%3%
3% (INDIA)
3%
Arab World
Asia Pacific
Africa
East Central Asia
Europe
Russia
India
North America
South America
GSM in IndiaGSM in India
Figures: March 2005
Bharti27%
BSNL22%
Spice 4%
IDEA13%
Hutch19%
BPL6%
Aircel4%
Reliance3%
MTNL2%
Bharti
BSNL
Hutch
IDEA
BPL
Aircel
Spice
Reliance
MTNL
GSM System ArchitectureGSM System Architecture
BSC
BSC
MSC
MS
MS
MS BTS
BTS
BTS
GMSC
PSTNISDNPDN
EIRAUC
HLR
VLR
Outgoing CallOutgoing Call
1.1. MS sends dialled number to MS sends dialled number to BSS BSS
2.2. BSS sends dialled number to BSS sends dialled number to MSCMSC
3,4 MSC checks VLR if MS is 3,4 MSC checks VLR if MS is allowed the requested allowed the requested service.If so,MSC asks BSS to service.If so,MSC asks BSS to allocate resources for call.allocate resources for call.
55 MSC routes the call to GMSCMSC routes the call to GMSC66 GMSC routes the call to local GMSC routes the call to local
exchange of called userexchange of called user7, 8,7, 8,9,10 Answer back(ring back) 9,10 Answer back(ring back)
tone is routed from called tone is routed from called user to MS via user to MS via GMSC,MSC,BSSGMSC,MSC,BSS
Incoming CallIncoming Call1.1. Calling a GSM Calling a GSM
subscriberssubscribers2.2. Forwarding call to Forwarding call to
GSMCGSMC3.3. Signal Setup to HLRSignal Setup to HLR4.4. 5. Request MSRN 5. Request MSRN
from VLRfrom VLR6.6. Forward responsible Forward responsible
MSC to GMSCMSC to GMSC7.7. Forward Call to Forward Call to
current MSCcurrent MSC8.8. 9. Get current 9. Get current
status of MSstatus of MS10.10.11. Paging of MS11. Paging of MS12.12.13. MS answers13. MS answers14.14.15. Security checks15. Security checks16.16.17. Set up 17. Set up
connectionconnection
HandoversHandovers
• Between 1 and 2 – Between 1 and 2 – Inter BTS / Intra BSCInter BTS / Intra BSC
• Between 1 and 3 –Between 1 and 3 –
Inter BSC/ Intra MSCInter BSC/ Intra MSC
• Between 1 and 4 – Between 1 and 4 –
Inter MSCInter MSC
Authentication in GSMAuthentication in GSM
Key generation and EncryptionKey generation and Encryption
Mobile RadioMobile RadioCellular Mobile Cellular Mobile
CommunicationsCommunications
Mobile Comms. PrinciplesMobile Comms. Principles
– Mobile uses a separate, temporary radio Mobile uses a separate, temporary radio channel to talk to the cell sitechannel to talk to the cell site
– Cell site talks to many mobiles at once, using Cell site talks to many mobiles at once, using one channel per mobileone channel per mobile
– Channels use a pair of frequencies for Channels use a pair of frequencies for communicationcommunication • The forward link for transmitting from the cell siteThe forward link for transmitting from the cell site • The reverse link for the cell site to receive calls from The reverse link for the cell site to receive calls from
the usersthe users
Mobile Comms. PrinciplesMobile Comms. Principles
• Radio energy dissipates over Radio energy dissipates over distance, so mobiles must stay near distance, so mobiles must stay near the base station to maintain the base station to maintain communicationscommunications
• BBasic structure of mobile networks asic structure of mobile networks includes telephone systems and includes telephone systems and radio servicesradio services
Mobile Comms. PrinciplesMobile Comms. Principles
• Where mobile radio service operates in a closed Where mobile radio service operates in a closed network and has no access to the telephone network and has no access to the telephone system, mobile telephone service allows system, mobile telephone service allows interconnection to the telephone networkinterconnection to the telephone network
Mobile Comms. PrinciplesMobile Comms. Principles
• Radio energy dissipates over Radio energy dissipates over distance, so mobiles must stay near distance, so mobiles must stay near the base station to maintain the base station to maintain communicationscommunications
• basic structure of mobile networks basic structure of mobile networks includes telephone systems and includes telephone systems and radio servicesradio services
Mobile Systems Using CellsMobile Systems Using Cells
• The cellular concept employs The cellular concept employs variable low-power levelsvariable low-power levels – cells are sized according to the cells are sized according to the
subscriber density and demand in a subscriber density and demand in a given areagiven area
• Cells can be added to accommodate Cells can be added to accommodate population growthpopulation growth
Cellular System ArchitectureCellular System Architecture
• In modern cellular telephony, rural and In modern cellular telephony, rural and urban regions are divided into areas urban regions are divided into areas according to specific provisioning according to specific provisioning guidelinesguidelines
• Deployment parameters, such as Deployment parameters, such as amount of cell-splitting and cell sizes, amount of cell-splitting and cell sizes, are determined by engineers are determined by engineers experienced in cellular system experienced in cellular system architecturearchitecture
CellsCells
• A cell is the basic geographic unit of A cell is the basic geographic unit of a cellular systema cellular system – The term The term cellularcellular comes from the honeycomb comes from the honeycomb
shape of the areas into which a coverage shape of the areas into which a coverage region is dividedregion is divided
– Cells are base stations transmitting over small Cells are base stations transmitting over small geographic areas that are represented as geographic areas that are represented as hexagonshexagons
– Size varies depending on the landscapeSize varies depending on the landscape
GSM OperationGSM Operation
Speech decoding
Channel decoding
De-interleaving
Burst Formatting
De-ciphering
DemodulationModulation
Ciphering
Burst Formatting
Interleaving
Channel Coding
Speech coding
Radio Interface
Speech Speech
13 Kbps
22.8 Kbps
22.8 Kbps
33.6 Kbps
33.6 Kbps
270.83 Kbps
GSM-Frame StructureGSM-Frame Structure
OPEN INTERFACES OF GSMOPEN INTERFACES OF GSM
• Network Switching Subsystem(NSS)Network Switching Subsystem(NSS)
• Base Station Subsystem(BSS)Base Station Subsystem(BSS)
• Network Management Network Management Subsystem(NMS) or Operation and Subsystem(NMS) or Operation and Support Subsystem(OSS)Support Subsystem(OSS)
• They connect with Air,A,O&M They connect with Air,A,O&M interfacesinterfaces
PROCEDURE OF CALL SET UP PROCEDURE OF CALL SET UP FROM MOBİLE USERFROM MOBİLE USER
SIGNALS AND PROTOCOLSSIGNALS AND PROTOCOLS
• STANDART MESSAGESSTANDART MESSAGES• SENDER WANTS TO SERVICESENDER WANTS TO SERVICE• OPERATOR ASK THAT YOU WANTS TO OPERATOR ASK THAT YOU WANTS TO
TALK ,BUT WHICH USERTALK ,BUT WHICH USER• OPERATOR CONNECT TO RECEIVEROPERATOR CONNECT TO RECEIVER• WHEN THE RECEIVER REPLIES TO WHEN THE RECEIVER REPLIES TO
CALL ,THE CALL STARTSCALL ,THE CALL STARTS• WHEN THE RECEIVER OR SENDER CLOSE WHEN THE RECEIVER OR SENDER CLOSE
THE PHONE , THE OPERATOR FINISH THE PHONE , THE OPERATOR FINISH CONNECTION TO EACH OTHERCONNECTION TO EACH OTHER
PROCEDURE OF SIGNALSPROCEDURE OF SIGNALS
COMMON CHANNEL COMMON CHANNEL SIGNALLING SYSTEM SIGNALLING SYSTEM
• MTP(MASSAGE TRANSFER PART)MTP(MASSAGE TRANSFER PART)
• TUP(TELEPHONE USER PART)TUP(TELEPHONE USER PART)
• SSCP(SIGNALLING CONNECTION AND SSCP(SIGNALLING CONNECTION AND CONTROL PART)CONTROL PART)