Presentation on GSM Network GSM-Introduction Architecture Technical Specifications Frame Structure Channels SecurityCharacteristics and featuresApplicationsContentsWhat is GSM ?Global System for Mobile (GSM) is a second generation cellular standard developed to cater voice services and data delivery using digital modulationGSM: History Developed by Group Spciale Mobile (founded 1982) which was an initiative of CEPT ( Conference of European Post and Telecommunication ) Aim : to replace the incompatible analog system Presently the responsibility of GSM standardization resides with special mobile group under ETSI ( European telecommunication Standards Institute ) Full set of specifications phase-I became available in 1990 Under ETSI, GSM is named as “ Global System for Mobile communication “ Today many providers all over the world use GSM (more than 135countries in Asia, Africa, Europe, Australia, America) More than 1300 million subscribers in world and 45 million subscriber in India.GSM in WorldGSM in IndiaGSM ServiceslTele-serviceslBearer or Data Services lSupplementary servicesTele Services Telecommunication services that enable voice communicationvia mobile phones Offered services- Mobile telephony- Emergency calling Bearer ServiceslInclude various data services for information transfer between GSM and other networks like PSTN, ISDN etc at rates from 300 to 9600 bpslShort Message Service (SMS) up to 160 character alphanumeric data transmission to/from the mobile terminallUnified Messaging Services(UMS)lGroup 3 faxlVoice mailboxlElectronic mailSupplementary ServicesCall 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 by the user Multi Party Call Conferencing - Link multiple calls together CLIP Caller line identification presentation CLIR Caller line identification restriction CUG Closed user groupGSM System ArchitectureBSCBSCMSCMSMSMSBTSBTSBTSGMSCPSTN ISDN PDNEIR AUC HLRVLRGSM System Architecture-IlMobile Station (MS) Mobile Equipment (ME) Subscriber Identity Module (SIM)lBase Station Subsystem (BSS) Base Transceiver Station (BTS) Base Station Controller (BSC)lNetwork Switching Subsystem(NSS) Mobile Switching Center (MSC) Home Location Register (HLR) Visitor Location Register (VLR) Authentication Center (AUC) Equipment Identity Register (EIR)System Architecture Mobile Station (MS)The Mobile Station is made up of two entities:Mobile Equipment (ME) 2.Subscriber Identity Module (SIM)System Architecture Mobile Station (MS) Mobile EquipmentlPortable,vehicle mounted, hand held device lUniquely identified by an IMEI (International Mobile Equipment Identity)lVoice and data transmission lMonitoring power and signal quality of surrounding cells for optimum handoverlPower level : 0.8W 20 Wl160 character long SMS. System Architecture Mobile Station (MS) contd.Subscriber Identity Module (SIM)lSmart card contains the International Mobile Subscriber Identity (IMSI)lAllows user to send and receive calls and receive other subscribed serviceslEncoded network identification details- Key Ki,Kc and A3,A5 and A8 algorithmslProtected by a password or PINlCan be moved from phone to phone contains key information to activate the phoneSystem Architecture 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 suppliersBase Transceiver Station (BTS)Base Station Controller (BSC)System Architecture Base Station Subsystem (BSS) Base Transceiver Station (BTS):lEncodes,encrypts,multiplexes,modulates and feeds the RF signals to the antenna.lFrequency hoppinglCommunicates with Mobile station and BSClConsists of Transceivers (TRX) unitsSystem Architecture Base Station Subsystem (BSS) Base Station Controller (BSC)lManages Radio resources for BTSlAssigns Frequency and time slots for all MSs in its arealHandles call set uplTranscoding and rate adaptation functionalitylHandover for each MSlRadio Power control lIt communicates with MSC and BTSSystem Architecture Network Switching Subsystem(NSS)Mobile Switching Center (MSC)lHeart of the network lManages communication between GSM and other networks lCall setup function and basic switchinglCall routing lBilling information and collection lMobility management - Registration - Location Updating - Inter BSS and inter MSC call handoff lMSC does gateway function while its customer roams to other network by using HLR/VLR.System Architecture Network Switching SubsystemlHome Location Registers (HLR)- permanent database about mobile subscribers in a large service area(generally one per GSM network operator) -database contains IMSI,MSISDN,prepaid/postpaid,roaming restrictions,supplementary ser