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و GSMساختار شبکه عملكرد هر كدام از اجزاي

آن

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ساختار شبکهMobile : بايد به صورتي باشد كه

در هر مکانی به مشترک سرويس دهی شود

با هر سرعتی مشترک سرويس دهی شود

مکان مشترک مشخص شود

هويت مشترک مشخص شود

سرويسی مورد درخواست مشترک ارايه شود

با تمام شبكه هاي ديگر ارتباط و تبادل داشته باشد

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GSM Subsystem & relationships

NSS

PLMN

PSTN

PSPDN

CSPDN

ISDN

NMS

BSS

MS

Control flow

User data flow

Access partCore part

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GSM Architecture

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GSM System Architecture

PSTN

Data Terminal

HLR/VLR

MSCBSC

OMC(Operation & Maintenance

Center)

OperationTerminal

BTS

Handset

A

X.25

A-bis SS7

Network sub-system PSTNRadiosub-system

Mobilestation

UM

SIMcard

GSM

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Mobile Station (MS)

The MS (Mobile Station) is a combination of terminal equipment

and subscriber data. ME (Mobile Equipment )

SIM( Subscriber Identity Module)

ME+ SIM MS

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SIM card

Uniquely Associated To A User

Stores User And Location Addresses

Supports Authentication And Encryption Mechanisms

Contains Personal Data

list of subscribed services RAM for user directory, SMS

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Smart Card Anatomy

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پایه های سیم کارت

پايه Vccپايه GNDپايه CLK پايه RSTپايه I/O پايهVpp

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Microprocessor Cards

Typical specification

• 16 bit CPU• 128 K ROM• 1 K bytes RAM• 32K EEPROM

Smart Card Technology

• Based on ISO 7816 defining Card size, contact layout, electrical characteristics I/O Protocols: byte/block based File Structure

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اجزای تشکیل دهنده میکروکنترلر

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PARAMETER COMMENT

ADMINISTRATIVE DATA

PIN/PIN2 Personal Identification Number

PUK/PUK2 PIN unblocking key required to unlock a SIM

SIM Service Table List of optional functionality of the SIM

Last Dialed Number Used to redial the last number

Language Used for the display language

SECURITY RELATED DATA

Algorithm A3 and A8 Used for authentication and to determine Kc

Key Ki Individual Value Known only to the SIN and HLR

Key Kc The result of A8, Ki and random number (RAND)

CKSN Ciphering key sequence number

SUBSCRIBER DATA

IMSI International Mobile Subscriber Identity

MSISDN Mobile Subscriber ISDN number

Access Control Classes Used for control of network access

Stored data in SIM Card

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PARAMETER COMMENT

ROAMING DATA

TMSI Temporary Mobile Subscriber Identity

Value of T3212 Timer used for location updating

Location Updating Status Determines if a location update is required

LAI Location Area Information

Network Color Codes (NCCs) of Restricted PLMNs

A SIM can hold up to 4 PLMNs after and unsuccessful location update. The oldest entry will be deleted when more than 4 restricted PLMNs are found

NCCs of Preferred PLMNsDecides which PLMN the MS should select if there is more than one to choose from, when the home PLMN is not available

PLMN DATA

NCC, Mobile Country Code (MCC), Mobile Network Code (MNC) of the Home PLMN

This provides the home country and network identification of the subscriber

Absolute Radio Frequency Channel Number (ARFCNs) of the Home PLMN

Frequencies for which the home PLMN is licensed

Stored data in SIM Card

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استانداردهای مربوط به سیم کارت

GSM• GSM 11.11 (SIM interface spec)• GSM 11.14 (SIM toolkit)• GSM 03.48 (OTA communication)• GSM11.17(SIM TEST APPROACH)

ISO• ISO 7810• ISO 7816

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Mobile station power classes

GSM 900 GSM 1800

8W 39dBm Vehicular 4W 36dBm Vehicular

5W 37dBm Portable 1W 30dBm Portable

2W 33dBm Portable 0.25W 24dBm Portable

0.8W 29dBm Portable

Usual Classes

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BSS: Base Station Subsystem

BTS )Base Transceiver Station( ----Transmitter, receiver and antennas

BSC )Base Station Controller( ----Management of several BTS

TC( Transcoder )---Adapt Bit rate to send MSC

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BTS

• provides GSM radio coverage within a cll

• comprises radio transmitting and receiving equipment (including antennas)

• associated signal processing• implementation of radio related

operations: slow frequency hopping

(SFH) discontinuous transmission

(DTX) Ciphering power control.

• Synchronization between MSs• Management of Signaling line

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BTS Power Classes

GSM

GSM 900 GSM 1800

320W 55dBm Class 1 20W 43dBm Class 1

160W 52dBm Class 2 10W 40dBm Class 2

80W 49dBm Class 3 5W 37dBm Class 3

40W 46dBm Class 4

20W 43dBm Class 5

10W 40dBm Class 6

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BSC

• A small switch with enhanced processing capability.

• Its responsibilities include: co-ordination and control of a number of BTSs traffic concentration low level switching operations network management interface to all radio elements radio channel management handover between BTSs within its domain scheduling of paging request passing system information e.g. LAI (Location Area Identity)

to BTSs for onward transmission queuing control of radio related operations: slow frequency hopping

(SFH); discontinuous transmission (DTX); ciphering and power control

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Functions BSC BTS

Management of radio channels X

Frequency hopping (FH) X X

Management of terrestrial channels X

Mapping of terrestrial onto radio channels X

Channel coding and decoding X

Rate adaptation X

Encryption and decryption X X

Paging X X

Uplink signal measurements X

Traffic measurement X

Authentication X

Location registry, location update X

Handover management X

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Point to point connection

Multi drop chain

Multi drop loop

BSC

Transmission between BSC and BTS

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Transcoder Speech Coding is used to enable the efficient

transmission at 13 Kbps or 6.5 Kbps service transcoding, changing air interface

rates to network rates e.g. converting speech from 13 kbit/s to 64 kbit/s

3 kbit/s is used for inband signaling TC can be located at BSC or MSC If is located near MSC , it can be multiplexed 4

lines in one PCM signals and increase efficiency of transmission

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NSS - Network and Switching Subsystem

Main task

• Call control

• Routing

• Locating

• Mobility management

• Signalling to other network

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NSS –Elements

MSC )Mobile Switching Centre-----(Management of all connections

HLR )Home Location Register( -----Associated to each PLMN

VLR )Visitor Location Register-----(Associated to each MSC

GMSC) Gateway MSC MSC-----( providing interconnection to other networks

AUC : Authentication Center----provide security of network

EIR : Equipment Identity Register---provide absolute information of user

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MSC (mobile switching center)

Switching functions Additional functions for mobility support Interworking functions via Gateway MSC (GMSC) Integration of several databases

Specific functions of a MSC

• Switching of 64 kbit/s channels

• Paging and call forwarding

• Termination of SS7 (signaling system no. 7)

• Mobility specific signaling

• Location registration and forwarding of location information

• Support of short message service (SMS)

• Generation and forwarding of accounting and billing information

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Visitor Location Register (VLR)

Local database:

• Data about all users currently in the domain of the VLR

• Includes roamers and non-roamers

• Associated to each MSC

Responsibilities of the VLR include:

• Executing supplementary service programs (outgoing calls

barred)

• Initiating authentication and ciphering

• Initiating paging

• Mapping of various identities (MSISDN, IMSI, TMSI, MSRN)

• Passing location information to HLR

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Connects mobile network to a fixed network, e.g. Entry point to a PLMN

Request routing information from the HLR and routes the connection to the local MSC

Gateway MSC (GMSC)

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Home Location Register (HLR)

central master database• data from every user that has subscribed to the operator,

includes: subscriber data

o IMSI - International Mobile Subscriber Identityo list of subscribed services with parameters and

restrictions location data

o current MSC/VLR address Responsibilities of the HLR include:

• management of service profiles• mapping of subscriber identities (MISDN, IMSI)• supplementary service control and profile updates • execution of supplementary service logic e.g. incoming

calls barred. • passing subscription records to VLR

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Authentication Center (AuC)

Associated to HLR

Search key: IMSI

Supports authentication and encryption

mechanisms

• Ki - subscriber secret authentication key

• A3 - authentication algorithm

• A8 - cipher key generation algorithm

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Equipment Identity Register (EIR)

stores mobile stations IMEI (International Mobile Equipment

Identity)

white list - mobile stations allowed to connect without

restrictions

black list - mobile stations locked (stolen or not type

approved)

gray list - mobile stations under observation for possible

problems

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Network Management Subsystem : NMS

Operation & management Center (OMC)

Control of the radio and network subsystems

• Event & Fault Management

• Configuration management

• Performance Management

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Event & Fault Management

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Configuration management

Maintain up to date

information about network

Management of radio

network

Software & hardware

management

Security management

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Performance management

Collect date and

measurement from BSC and

MSC

calculate the KPI

• Key Performance Indicator

Compare the network with

desire performance

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Application Service Centers

• Short Message Service Center

(SMSC) provide short message services usually connect to MSC

• Unstructured Supplementary

Service Data Center (USSDC) provide USSD service in the form of

*ID*ID*info# usually connect to HLR

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GSM Services

GSM Services

Supplementary Services

Basic Services

Bearer Services

TeleServices

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توضيح کد مشخصه

GSM

شرح سرويس

مهمترين سرويس براي سيستمهاي موبايل، مکالمه عادي شامل مکالمات

اضطراري

T11 )تلفني( صحبت

امکان برقراري مکالمات اضطراري بطور اتوماتيک

T12 صحبت )تماس اضطراري(

براي دريافت پيام کوتاه T21 (Mobile Terminatedپيام کوتاه )

براي ارسال پيام کوتاه T22 (Mobile Originatedپيام کوتاه )

براي دريافت پيامهاي کوتاه منتشر شده T23 (Cell Broadcastپيام کوتاه )

T61 3ارتباط فاکس گروه

براي ارسال و دريافت پيامهاي فاکس T62 3ارتباط فاکس اتوماتيک گروه

GSM TeleServices

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Bearer Service Give the subscriber the capacity required to

transmit appropriate signals between certain access points

• Asynchronous data• Synchronous data• Packet switched assembler/

disassembler access• Alternate speech and data

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Supplementary Services:

• Advice of charge-AOC

• Alternate Line Services (ALS)-personal or business

• Barring of all incoming calls-BAIC

• Barring of all Incoming calls when roaming outside the HPLMN

• Barring of Incoming Calls when abroad

• Barring of outgoing calls-BOC

• Barring of outgoing International Calls-BOIC

• Barring of outgoing International calls excluding those directed to the HPLMN country

• Call forwarding on mobile subscriber busy-CFB

• Call forwarding on no answer-CFNA

• Call forwarding unconditional -CFU

• Call hold

• Call Waiting-CW

Services