gsm network dilip
TRANSCRIPT
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Presentation on GSMPresentation on GSM
NetworkNetwork
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What is GSM ?What is GSM ?
Global System for Mobile (GSM) is a
second generation cellular standarddeveloped to cater voice services and
data delivery using digital modulation
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GSM: HistoryGSM: History
Developed by Group Special Mobile (founded 1982) which wasaninitiativeof CEPT ( Conferenceof European Postand
Telecommunication )
Aim : toreplacetheincompatibleanalogsystem
PresentlytheresponsibilityofGSM standardizationresides with special
mobilegroupunderETSI ( Europeantelecommunication Standards
Institute )
UnderETSI, GSM isnamedas GlobalSystem forMobile
communication
Todaymanyprovidersalloverthe worlduseGSM (morethan 135
countriesin Asia, Africa, Europe, Australia, America)
Morethan 1300 millionsubscribersin worldand 45 millionsubscriberin
India.
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GSM inWorldGSM inWorld
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
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GSM in IndiaGSM in India
Figures: March 2005
Bharti
27%
BSNL
22%
Spice4%
IDEA
13%
Hutch
19%
BPL
6%
Aircel4%
Reliance
3%
MTNL2%
BhartiBSNL
Hutch
IDEA
BPL
Aircel
Spice
Reliance
MTNL
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GSM ServicesGSM Services
Tele-services
Bearer orData Services
Supplementary services
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Tele ServicesTele Services
Telecommunication services that enable voice communication
via mobile phones
Offered services
- Mobile telephony
- Emergency calling
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Bearer ServicesBearer Services
Include various data services for information transferbetween GSM and other networks like PSTN,ISDN etc atrates from 300 to 9600 bps
Short Message Service (SMS)
up to 160 character alphanumeric data transmissionto/from the mobile terminal
Unified Messaging Services(UMS)
Group 3 fax
Voice mailbox
Electronic mail
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Supplementary ServicesSupplementary Services
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 bythe user
Multi Party Call Conferencing - Link multiple calls together
CLIP Caller line identification presentation
CLIRCaller line identification restriction
CUG Closed user group
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GSM System ArchitectureGSM System Architecture
BSC
BSC
MSC
MS
MS
MS BTS
BTS
BTS
GMSC
PSTNISDN
PDN
EIRAUC
HLR
VLR
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GSM System ArchitectureGSM System Architecture--II
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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System ArchitectureSystem Architecture
Base Station Subsystem (BSS)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)
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System ArchitectureSystem Architecture
Base Station Subsystem (BSS)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 ofTransceivers (TRX) units
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System ArchitectureSystem Architecture
Base Station Subsystem (BSS)Base Station Subsystem (BSS)
Base Station Controller (BSC)
Manages Radio resources for BTS
Assigns Frequency and time slots for all MSs in its area
Handles call set up
Transcoding and rate adaptation functionality
Handover for each MS
Radio Power control
It communicates with MSC and BTS
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System ArchitectureSystem Architecture
Network Switching Subsystem(NSS)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
- Inter BSS and inter MSC call handoff
MSC does gateway function while its customer roams to other networkby using HLR/VLR.
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System ArchitectureSystem Architecture
Network Switching SubsystemNetwork Switching Subsystem
Home Location Registers (HLR)
- permanent database about mobile subscribers in a large servicearea(generally one per GSM network operator)
- database contains IMSI,MSISDN,prepaid/postpaid,roamingrestrictions,supplementary services.
Visitor Location Registers (VLR)
- Temporary database which updates whenever new MS enters its area,by HLRdatabase
- 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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System ArchitectureSystem Architecture
Network Switch
ing SubsystemNetwork Switch
ing Subsystem Authentication Center (AUC)
- Protects against intruders in air interface
- Maintains authentication keys and algorithms and providessecurity 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 BlackList and the Gray List
- Only one EIRper PLMN
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Outgoing CallOutgoing Call
1. MS sends dialled number to BSS2. BSS sends dialled number to MS
3,4 MSC checks VLRif MS isallowed the requested service.If
so,MS
C
asks BSS to allocateresources for call.
5 MSC routes the call to GMSC
6 GMSC routes the call to localexchange of called user
7, 8,9,10 Answer back(ring back) tone is
routed from called user to MS viaGMSC,MSC,BSS
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Incoming CallIncoming Call1. Calling a GSM
subscribers
2. Forwarding call to
GSMC3. Signal Setup to HLR
4. 5. Request MSRN fromVLR
6. Forward responsibleMSC to GMSC
7. Forward Call to currentMSC
8. 9. Get current status of
MS10.11. Paging of MS
12.13. MS answers
14.15. Security checks
16.17. Set up connection
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Thanks !Thanks !
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Questions ?Questions ?