GSM NETWORK ARCHITECTURE
BY: ENG. Waleed Elsafoury Copyright © 2013 Waleed Elsafoury
GSM NETWORK ARCHITECTURE •
GSM NETWORK ARCHITECTURE
GSM NETWORK ARCHITECTURE
GSM NETWORK ARCHITECTURE -The Mobile station (MS) Modes of MS attached idle
detached
active
IMSI de.
registration
Ongoing call
LA Updating
Handover
Implicit de.
paging
Monitoring power & quality of its BTS
roaming
Monitoring power of neighboring BTSs
GSM NETWORK ARCHITECTURE
Types of MSs Vehicle mounted MS Mounted to dashboard of vehicle. Antenna mounted on outside. More powerful. Transportable MS Can be handheld. Antenna is not connected to handset. Handheld MS Hand carried Antenna connected to handset. Pocket-sized. Can be vehicle mounted.
GSM NETWORK ARCHITECTURE
The Mobile station (MS) 1- Mobile equipment (ME) ●
it is the terminal used by user
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Can be purchased from any store
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Without SIM no calls can be made
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It has an International Mobile Equipment Identity (IMEI)
IDENTITY NUMBERS
GSM NETWORK ARCHITECTURE 2- Subscriber identity module (SIM) An electronic microchip for storing information
GSM NETWORK ARCHITECTURE 2- Subscriber identity module (SIM)
GSM NETWORK ARCHITECTURE 2- Subscriber identity module (SIM)
IDENTITY NUMBERS
IDENTITY NUMBERS
IDENTITY NUMBERS
IDENTITY NUMBERS
IDENTITY NUMBERS
GSM NETWORK ARCHITECTURE -The base station subsystem (BSS) 1- The Base Transceiver station (BTS) ●
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BS contains the RF transmission equipment Each cell has one BS It has an International cell global Identity (CGI) It performs Power amplification,channel coding, ciphering
GSM NETWORK ARCHITECTURE
The Site:
The Shelter
The Tower
GSM NETWORK ARCHITECTURE Base Transceiver station
GSM NETWORK ARCHITECTURE Base Transceiver station
GSM NETWORK ARCHITECTURE Base Transceiver station
Alarm Board
Site Controller (HIISC)
Circuit Breaker Card (CBC)
Power Supply Units (PSU)
Cooling Fans
CTU2
Power Supply
Tx Blocks
GSM NETWORK ARCHITECTURE Base Transceiver station
GSM NETWORK ARCHITECTURE Base Transceiver station
GSM NETWORK ARCHITECTURE Base Transceiver station
GSM NETWORK ARCHITECTURE
GSM NETWORK ARCHITECTURE
GSM NETWORK ARCHITECTURE
GSM NETWORK ARCHITECTURE
GSM NETWORK ARCHITECTURE 2-
The base station controller (BSC)
-It carries out all control functions in the BSS as: ●
Paging
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Channel allocation
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Dynamic power control
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Handover
The base station controller (BSC)
GSM NETWORK ARCHITECTURE The base station controller (BSC)
Remote BTS BTS
BTS BSC Co-located BTS
The base station controller (BSC)
The base station controller (BSC)
The base station controller (BSC)
The base station controller (BSC)
GSM NETWORK ARCHITECTURE BSS Link configuration - Cascade
BTS BSC BTS
BTS
BTS
BTS
GSM NETWORK ARCHITECTURE BSS Link configuration - loop
BTS BSC
BTS
BTS
BTS
GSM NETWORK ARCHITECTURE BSS Link configuration - Star
BTS
BTS
BTS
BTS BTS BSC
GSM NETWORK ARCHITECTURE 3- The transcoding and rate adaptation unit (TRAU) -
It is used for speech compression/decompression
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Also adaptation of data to the requirement of the air interface
16 13
16
BSC
Master text styles evel ● Third level ● Fourth level ● Fifth level
16 16 16 16
16 16 TRAU
64 64 64 64
MSC
VLR
ď‚— Transcoding and rate adaptation unit
GSM NETWORK ARCHITECTURE -
The Mobile service switching center (MSC)
-It is an electronic computerized exchange provides the interface between MS and the fixed network -It will not contain any subscriber parameters ●
Switching
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Charging
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call routing
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Communication with HLR and VLR
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Communication with other MSCs
Mobile Services Switching Centre
GSM NETWORK ARCHITECTURE -
The MSC is connected to: 1. HLR (Home location register) 2. VLR (Visitor location register) 3. AUC (Authentication Center) 4. EIR (Equipment identity register) Click to edit Master text styles Second level ● Third level ● Fourth level ● Fifth level
GSM NETWORK ARCHITECTURE 1. HLR (Home location register) 2. The centralized database that stores and manages 3. all mobile subscription parameters 4. HLR contains : -
Subscriber identification numbers (IMSI,MSISDN)
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Subscriber current location information (MSC/VLR)
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Subscriber authentication information
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Charging
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Billing method
GSM NETWORK ARCHITECTURE 1. HLR (Home location register) Click to edit Master text styles Second level ● Third level ● Fourth level ● Fifth level
GSM NETWORK ARCHITECTURE 2. VLR (Visitor location register) ● A temporary storage location for subscription ● information for MSs which are within MSC service area
●VLR contains : -
Mobile status (free, busy,…etc)
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Temporary MS identity (TMSI)
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Temporary MS roaming number (MSRN)
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Supplementary service information
GSM NETWORK ARCHITECTURE 3. Authentication
- It is a processor system that performs the authenticatio function
AUC IMSI
Ki
Database IMSI,Ki
RAND A3
RAND
SRES Triplet
A8
Kc
Request for Triplet from HLR,VLR
Triplet
GSM NETWORK ARCHITECTURE 3. Authentication
GSM NETWORK ARCHITECTURE 4. EIR (Equipment identity register) ● As the subscriber and equipment are separate in GSM so we ● use a separate authentication process for MS equipment ● EIR is a centralized database for validation of international ● mobile equipment identity (IMEI)
●EIR contains 3 lists: -
White list (for valid MS equipment)
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Black list (for stolen or denied service MS)
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Gray list (for mal-performance MS [e.g. faulty software] )
EIR
Black list
White list Gray list
GSM NETWORK ARCHITECTURE 3-The Operation and maintenance center (OMC):A-The Operation and Maintenance Center for Radio part (BSS) (OMC-R)
The Operation and Maintenance Center for switching parts (OMC-S)
GSM NETWORK ARCHITECTURE The Operation and maintenance center (OMC)
GSM NETWORK ARCHITECTURE
- Geographic network areas
GSM NETWORK ARCHITECTURE
GSM NETWORK ARCHITECTURE
GSM NETWORK ARCHITECTURE
IDENTITY NUMBERS
GSM NETWORK ARCHITECTURE
- Cell
IDENTITY NUMBERS
Vodafone 2G Coverage
Mobinil 2G Coverage