GSM NETWORK ARCHITECTURE BY ENG Waleed Elsafoury GSM

GSM NETWORK ARCHITECTURE BY: ENG. 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 HO Implicit de. paging Monitoring power & quality of its BTS roaming Monitoring power of neighboring BTSs

GSM NETWORK ARCHITECTURE Types of MSs Vehicle mounted MS q Mounted to dashboard of vehicle. q Antenna mounted on outside. q More powerful. Transportable MS q Can be handheld. q Antenna is not connected to handset. Handheld MS q Hand carried q Antenna connected to handset. q Pocket-sized. q Can be vehicle mounted.

GSM NETWORK ARCHITECTURE -The Mobile station (MS) 1 - Mobile equipment (ME) Øit is the terminal used by user ØCan be purchased from any store ØWithout SIM no calls can be made ØIt 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)

IDENTITY NUMBERS

GSM NETWORK ARCHITECTURE -The base station subsystem (BSS) 1 - The Base Transceiver station (BTS) Øit contains the RF transmission equipment ØEach cell has one BTS ØEach BTS consists of one or more transceiver ØIt has an International cell global Identity (CGI) ØIt performs channel coding, ciphering and modulation

GSM NETWORK ARCHITECTURE �Base Transceiver station

GSM NETWORK ARCHITECTURE Base Transceiver station

GSM NETWORK ARCHITECTURE �Base Transceiver station

GSM NETWORK ARCHITECTURE Base Transceiver station

GSM NETWORK ARCHITECTURE

GSM NETWORK ARCHITECTURE 2 - The base station controller (BSC) -It carries out all control functions in the BSS as: 1. Paging 2. Channel allocation 3. Dynamic power control 4. Handover 5. Frequency hopping

The base station controller (BSC)

GSM NETWORK ARCHITECTURE The base station controller (BSC) Remote BTS BTS BSC Co-located BTS

The base station controller (BSC)

GSM NETWORK ARCHITECTURE BSS Link configuration - Cascade BTS BSC BTS BTS

GSM NETWORK ARCHITECTURE BSS Link configuration - loop BTS BSC BTS BTS

GSM NETWORK ARCHITECTURE BSS Link configuration - Star BTS BTS BTS BSC

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 16 13 16 BSC 16 16 16 TRAU 64 64 MSC VLR

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 1. Charging 2. Switching and call routing 3. Communication with HLR and VLR 4. Communication with other MSCs 5. Control of connected BSCs

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)

GSM NETWORK ARCHITECTURE 1. HLR (Home location register) - The centralized database that stores and manages all mobile subscription parameters - HLR contains : Ø Subscriber identification numbers (IMSI, MSISDN) Ø Subscriber current location information (MSC/VLR) Ø Subscriber authentication information Ø Charging Ø Subscriber type

GSM NETWORK ARCHITECTURE 1. HLR (Home location register)

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 : Ø Mobile status (free, busy, …etc) Ø Temporary MS identity (TMSI) Ø Temporary MS roaming number (MSRN) Ø Supplementary service information

GSM NETWORK ARCHITECTURE 3. Authentication - It is a processor system that performs the authentication function AUC IMSI Ki Database IMSI, Ki RAND A 3 RAND SRES Triplet A 8 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: Ø White list (for valid MS equipment) Ø Black list (for stolen or denied service MS) Ø 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) B-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

IDENTITY NUMBERS

GSM NETWORK ARCHITECTURE - Cell

IDENTITY NUMBERS