Mobile CommunicationsChapter 4 WirelessTelecommunication Systems Market DECT GSM TETRA. Overview UMTS IMT 2000 Services Sub systems Components Mobile phone subscribers worldwide.Subscribers million TDMA totalCDMA total600 PDC totalAnalogue total.Total wirelessPrediction 1998 1996 1997 1998 1999 2000 2001 2002 Development of mobile telecommunication systemsIS 136 DECT.EDGE IMT SCUTRA FDD W CDMAUTRA TDD TD CDMAIS 95 IMT MCcdma2000 1X.cdmaOne cdma2000 1X EV DO1G 2G 2 5G 3G 3X GSM Overview formerly Groupe Sp ciale Mobile founded 1982 now Global System for Mobile Communication. Pan European standard ETSI European TelecommunicationsStandardisation Institute simultaneous introduction of essential services in three phases 1991 1994 1996 by the European telecommunication administrations Germany D1 and D2 . seamless roaming within Europe possible today many providers all over the world use GSM more than 184countries in Asia Africa Europe Australia America more than 747 million subscribers more than 70 of all digital mobile phones use GSM. over 10 billion SMS per month in Germany 360 billion year worldwide Performance characteristics of GSM wrt analog sys Communication mobile wireless communication support for voice and dataTotal mobility. international access chip card enables use of access points ofdifferent providersWorldwide connectivity one number the network handles localizationHigh capacity. better frequency efficiency smaller cells more customers per cellHigh transmission quality high audio quality and reliability for wireless uninterrupted phonecalls at higher speeds e g from cars trains Security functions. access control authentication via chip card and PIN Disadvantages of GSMThere is no perfect system no end to end encryption of user data no full ISDN bandwidth of 64 kbit s to the user no transparent B . reduced concentration while driving electromagnetic radiation abuse of private data possible roaming profiles accessible high complexity of the system. several incompatibilities within the GSM standards GSM Mobile ServicesGSM offers several types of connections voice connections data connections short message service. multi service options combination of basic services Three service domains Bearer Services Telematic Services Supplementary Services.bearer servicestransit source TE MT GSM PLMN network destination TER S Um PSTN ISDN network U S R tele services. Bearer Services Telecommunication services to transfer data between access points Specification of services up to the terminal interface OSI layers 1 3 Different data rates for voice and data original standard data service circuit switched . synchronous 2 4 4 8 or 9 6 kbit s asynchronous 300 1200 bit s data service packet switched synchronous 2 4 4 8 or 9 6 kbit s asynchronous 300 9600 bit s.Today data rates of approx 50 kbit s possible will be covered later Tele Services I Telecommunication services that enable voice communicationvia mobile phones All these basic services have to obey cellular functions security.measurements etc Offered services mobile telephonyprimary goal of GSM was to enable mobile telephony offering thetraditional bandwidth of 3 1 kHz. Emergency numbercommon number throughout Europe 112 mandatory for allservice providers free of charge connection with the highestpriority preemption of other connections possible Multinumbering.several ISDN phone numbers per user possible Tele Services IIAdditional services Non Voice Teleservices group 3 fax. voice mailbox implemented in the fixed network supporting the mobileterminals electronic mail MHS Message Handling System implemented in the fixed Short Message Service SMS alphanumeric data transmission to from the mobile terminal using the.signaling channel thus allowing simultaneous use of basic services and Supplementary services Services in addition to the basic services cannot be offeredstand alone Similar to ISDN services besides lower bandwidth due to the.radio link May differ between different service providers countries andprotocol versions Important services identification forwarding of caller number. suppression of number forwarding automatic call back conferencing with up to 7 participants locking of the mobile terminal incoming or outgoing calls Architecture of the GSM system.GSM is a PLMN Public Land Mobile Network several providers setup mobile networks following the GSM standard withineach country components MS mobile station . BS base station MSC mobile switching center LR location register subsystems RSS radio subsystem covers all radio aspects. NSS network and switching subsystem call forwarding handover switching OSS operation subsystem management of the network GSM overviewNSS fixed networkVLR MSC MSC. GSM elements and interfacesradio cellUm radio cellRSS BTS MSNSS signaling.ISDN PSTNEIR AUC OMC GSM system architectureradio network and fixedsubsystem switching subsystem partner networks.BTS MSC PSTN System architecture radio subsystemradio network and switchingsubsystem subsystemComponents. MS Mobile Station Um BSS Base Station Subsystem Abis consisting of BTS Base Transceiver Station BTS sender and receiver. BSC Base Station Controller controlling several transceiversInterfaces Um radio interfaceBTS Abis standardized open interface with.16 kbit s user channels A standardized open interface with64 kbit s user channels System architecture network and switching subsystemnetwork fixed partner.subsystem networks Components MSC Mobile Services Switching Center ISDN IWF Interworking Functions ISDN Integrated Services Digital Network PSTN Public Switched Telephone Network .EIR PSPDN Packet Switched Public Data Net CSPDN Circuit Switched Public Data Net Databases HLR Home Location Register VLR VLR Visitor Location Register .ISDN EIR Equipment Identity Register Radio subsystemThe Radio Subsystem RSS comprises the cellular mobile network up tothe switching centers Components. Base Station Subsystem BSS Base Transceiver Station BTS radio components including sender receiver antenna if directed antennas are used one BTS can cover several cells Base Station Controller BSC switching between BTSs controlling BTSs managing of network resources mapping of radio channels U m onto terrestrial.channels A interface BSS BSC sum BTS interconnection Mobile Stations MS GSM cellular networksegmentation of the area into cells.possible radio coverage of the cellidealized shape of the cell use of several carrier frequencies not the same frequency in adjoining cells cell sizes vary from some 100 m up to 35 km depending on user.density geography transceiver power etc hexagonal shape of cells is idealized cells overlap shapes depend ongeography if a mobile user changes cells handover of the connection to the neighbor cell. Example coverage of GSM networks www gsmworld com T Mobile GSM 900 1800 Berlin Vodafone GSM 900 1800 e plus GSM 1800 O2 GSM 1800 Base Transceiver Station and Base Station ControllerTasks of a BSS are distributed over BSC and BTS. BTS comprises radio specific functions BSC is the switching center for radio channelsFunctions BTS BSCManagement of radio channels XFrequency hopping FH X X.Management of terrestrial channels XMapping of terrestrial onto radio channels XChannel coding and decoding XRate adaptation XEncryption and decryption X X.Paging X XUplink signal measurements XTraffic measurement XAuthentication XLocation registry location update X.Handover management X Mobile stationTerminal for the use of GSM services A mobile station MS comprises several functional groups MT Mobile Terminal . offers common functions used by all services the MS offers corresponds to the network termination NT of an ISDN access end point of the radio interface Um TA Terminal Adapter terminal adaptation hides radio specific characteristics. TE Terminal Equipment peripheral device of the MS offers services to a user does not contain GSM specific functions SIM Subscriber Identity Module personalization of the mobile terminal stores user parameters. Network and switching subsystemNSS is the main component of the public mobile network GSM switching mobility management interconnection to other networks system Components Mobile Services Switching Center MSC .controls all connections via a separated network to from a mobile terminalwithin the domain of the MSC several BSC can belong to a MSC Databases important scalability high capacity low delay Home Location Register HLR central master database containing user data permanent and semi permanent.data of all subscribers assigned to the HLR one provider can have several Visitor Location Register VLR local database for a subset of user data including data about all user currentlyin the domain of the VLR Mobile Services Switching Center.The MSC mobile switching center plays a central role in GSM switching functions additional functions for mobility support management of network resources interworking functions via Gateway MSC GMSC . integration of several databases Functions of a MSC specific functions for paging and call forwarding termination of SS7 signaling system no 7 mobility specific signaling. location registration and forwarding of location information provision of new services fax data calls support of short message service SMS generation and forwarding of accounting and billing information Operation subsystem.The OSS Operation Subsystem enables centralized operation management and maintenance of all GSM subsystems Components Authentication Center AUC generates user specific authentication parameters on request of a VLR. authentication parameters used for authentication of mobile terminals andencryption of user data on the air interface within the GSM system Equipment Identity Register EIR registers GSM mobile stations and user rights stolen or malfunctioning mobile stations can be locked and sometimes even. Operation and Maintenance Center OMC different control capabilities for the radio subsystem and the network subsystem GSM TDMA FDMA935 960 MHz124 channels 200 kHz .890 915 MHz124 channels 200 kHz higher GSM frame structuresGSM TDMA frame1 2 3 4 5 6 7 8.GSM time slot normal burst guard guardspace tail user data S Training S user data tail space3 bits 57 bits 1 26 bits 1 57 bits 3 GSM hierarchy of frames.hyperframe0 1 2 2045 2046 2047 3 h 28 min 53 76 ssuperframe0 1 2 48 49 500 1 24 25.multiframe0 1 24 25 120 ms0 1 2 48 49 50 235 4 ms0 1 6 7 4 615 msburst 577 s. GSM protocol layers for signalingMS BTS BSC MSCRR BTSM BTSM SS7 SS7LAPDm LAPDm LAPD LAPDradio radio PCM PCM PCM PCM.16 64 kbit s 64 kbit s 2 048 Mbit s Mobile Terminated Call1 calling a GSM subscriber2 forwarding call to GMSC.3 signal call setup to HLR 44 5 request MSRN from VLR 56 forward responsible 3 6 14 15MSC to GMSC calling 7PSTN GMSC MSC.7 forward call to station 1 2current MSC 10 10 13 108 9 get current status of MSBSS BSS BSS10 11 paging of MS 11 11 11.12 13 MS answers14 15 security checks 11 1216 17 set up connection Mobile Originated Call1 2 connection request.3 4 security check5 8 check resources free circuit 9 10 set up callPSTN GMSC MSCMS MTC BTS MS MOC BTS.paging requestchannel request channel requestimmediate assignment immediate assignmentpaging response service requestauthentication request authentication request.authentication response authentication responseciphering command ciphering commandciphering complete ciphering completesetup setupcall confirmed call confirmed.assignment command assignment commandassignment complete assignment completealerting alertingMobile Communications Subject: Wireless Telecommunication Systems Author: Jochen H. Schiller Last modified by: Mahendran Velauthapillai Created Date: 11/3/1997 3:44:45 PM Document presentation format: On-screen Show Company: FU Berlin, Germany Other titles