GSM

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CH 2
GSM NETWORK ARCHITECTURE
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GSM NETWORK ARCHITECTURE

• In this chapter we will see
• GSM NETWORK ARCHITECTURE
• The Radio Subsystem
• The Network Switching Subsystem
• The Operation and maintenance Subsystem
• Geographic network areas

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GSM NETWORK ARCHITECTURE

• GSM NETWORK ARCHITECTURE

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GSM NETWORK ARCHITECTURE
OMC
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GSM NETWORK ARCHITECTURE
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GSM NETWORK ARCHITECTURE
-The Mobile station (MS)
Monitoring power quality of its BTS
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GSM NETWORK ARCHITECTURE

• -The Mobile station (MS)
• 1- Mobile equipment (ME)
• it is the terminal used by user
• Can be purchased from any store
• Without SIM no calls can be made
• It has an International Mobile Equipment Identity
  (IMEI)

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IDENTITY NUMBERS
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GSM NETWORK ARCHITECTURE
2- Subscriber identity module (SIM)
An electronic microchip for storing information
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IDENTITY NUMBERS
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IDENTITY NUMBERS
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IDENTITY NUMBERS
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IDENTITY NUMBERS
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IDENTITY NUMBERS
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GSM NETWORK ARCHITECTURE

• -The base station subsystem (BSS)
• 1- The Base Transceiver station (BTS)
• it contains the RF transmission equipment
• Each cell has one BTS
• Each BTS consists of one or more transceiver
• It has an International cell global Identity
  (CGI)
• It has Base station identity code (BSIC)
• It performs channel coding, ciphering and
  modulation

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Different elements of RBS or BTS
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Different elements of RBS or BTS

• DXU Distribution Switch Unit
• TRU Transceiver unit
• CDU Combining and Distribution Unit
• ECU Energy Control Unit
• ? ECU contains PSU,BFU, AC connection unit
• ? PSU Power Supply Unit
• ? BFU Battery Fuse Unit

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• Base Transceiver station

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GSM NETWORK ARCHITECTURE

• 2- The base station controller (BSC)
• -It carries out all control functions in the BSS
  as
• Paging
• Channel allocation
• Dynamic power control
• Handover
• Frequency hopping

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GSM NETWORK ARCHITECTURE

• The base station controller (BSC)

Remote BTS
BTS
BTS
BSC
Co-located BTS
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GSM NETWORK ARCHITECTURE

• 3- The transcoding and rate adaptation unit
  (TRAU)
• It is used for speech compression/decompression
• Also adaptation of data to the requirement of the
  air interface

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64
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MSC
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BSC
VLR
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16V
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16
16
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64
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• Transcoding and rate adaptation unit

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GSM NETWORK ARCHITECTURE
BSS Link configuration
- Cascade
BTS
BSC
BTS
BTS
BTS
BTS
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GSM NETWORK ARCHITECTURE
BSS Link configuration
- loop
BTS
BSC
BTS
BTS
BTS
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GSM NETWORK ARCHITECTURE
BSS Link configuration
- Star
BTS
BTS
BTS
BTS
BTS
BSC
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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
• Charging
• Switching and call routing
• Communication with HLR and VLR
• Communication with other MSCs
• Control of connected BSCs

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Mobile Services Switching Centre
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GSM NETWORK ARCHITECTURE

• The MSC is connected to
• HLR (Home location register)
• VLR (Visitor location register)
• AUC (Authentication register)
• EIR (Equipment identity register)

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GSM NETWORK ARCHITECTURE

• HLR (Home location register)
• The centralized database that stores and manages
• all mobile subscription parameters
• HLR contains
• Subscriber identification numbers (IMSI,MSISDN)
• Subscriber current location information (MSC/VLR)
• Subscriber authentication information
• Charging
• Subscriber type

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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)
• Temporary MS identity (TMSI)
• Temporary MS roaming number (MSRN)

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GSM NETWORK ARCHITECTURE

• Authentication
• - It is a processor system that performs the
  authentication function

AUC
IMSI
Ki
Database IMSI,Ki
RAND
Request for Triplet from HLR,VLR
A8
A3
Triplet
RAND
SERS
Kc
Triplet
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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)
• Black list (for stolen or denied service MS)
• Gray list (for mal-performance MS
• e.g. faulty software )

EIR
Black list
White list
Gray list
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GSM NETWORK ARCHITECTURE

• 3-The Operation and maintenance center (OMC)-
• A-The Operation and Maintenance Center for Radio
  part (BSS) (OMC-R)

B-The Operation and Maintenance Center for
switching parts (OMC-S)
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GSM NETWORK ARCHITECTURE
The Operation and maintenance center (OMC)
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GSM NETWORK ARCHITECTURE
- Geographic network areas
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GSM NETWORK ARCHITECTURE
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GSM NETWORK ARCHITECTURE
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GSM NETWORK ARCHITECTURE
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IDENTITY NUMBERS
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IDENTITY NUMBERS
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GSM NETWORK ARCHITECTURE
- Cell
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IDENTITY NUMBERS
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IDENTITY NUMBERS
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The base station controller (BSC)