Mobile Apps Testing Tele communication Doc

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Mobile Apps Testing Tele communication Doc

  1. 1. www.h2kinfosys.com Email: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 Introductionto telecommunication Telecommunication -Communicationatdistance through signalsofvariednaturecoming fromatransmitted toreceiver Signals: Lights,Sounds,butnotin secured,nofastinformation Electromagneticenergy,isable totransportinformation inanextremelyfast way In1809,ThomasS.Sommeringproposedatelegraphicsystemcomposedofabattery,35wires(onefor eachletterandnumber) andagroupofsensorsmadeofgold,whichweresubmergedin awatertank:whena signalwas passingfromoneofthosewires,electricalcurrent would splitwatermolecules,and smalloxygen bubbleswould bevisiblenearthatsensor 1843,the yearin which SamuelMorseproposedawaytoassigneachletterandnumbertoaternary code (point,line, and space).Thiswayturnedouttobeextremelyconvenientandmoreaffordable than Sommering’sidea,especially intermsofreducedcircuitry(you wouldn’tneedanymoreawireforeach symbol).Meanwhile, technologybecameadvancedenough tofindawaytoconvertthosesignalsinaudible (orsometimesgraphic)signals.Thecombination ofthese twofactorsquicklydeterminedthesuccessof Morse’ssymbolcode,which wecanstillfindusedtoday Sevenyears later,AntonioMeucciandGrahamBellindependentlymanagedtobuilda prototype ofan early telephone(’soundatdistance’)machine.SinceMeuccididn’thavethemoneytopatenthisinvention (thecost was$250atthetime),Bellmanagedtoregisteritfirst. Bothwith telegraphsandtelephones,theneed fora distributedandreliablecommunicationnetworksoon becameevident.Routingissueswerefirstsolved by meansofhuman operatorsandcircuit commutation:the PSTN(PublicSwitchedTelephoneNetwork)wasborn. However,thissystemdidn’tguaranteetheprivacy and secrecyofconversations,andeffortstowardsthedevelopmentofan automaticcircuit commutationwere made.
  2. 2. www.h2kinfosys.com Email: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 EvolutionofGSM:(GlobalSystemfor Mobilecommunication) GSM(2G) GPRS(GeneralPacketRadioService)(2.5G)-dataspeedsofupto 171.2Kbps EDGE(EnhancedDataratefor GSMEvolution)(2.5G)-dataratesto384 Kbps if/whendeployed HighSpeed CircuitSwitchedData(HSCSD)(2.5G)-speedsof upto64 Kbps. However,HSCSDperpetuatestheinefficientuseof spectrumandtransmissionthatis relegatedby any circuitswitchedmechanism 3G(CDMA2000)-provideupto 2 Mbps LongTermEvolution(4G)
  3. 3. GSMhistory In1982,theEuropeanConferenceofPostalandTelecommunicationsAdministrations(CEPT)createdtheGroupeSpécia lMobile(GSM)todevelopastandardforamobile telephonesystemthatcouldbe usedacrossEurope.[6]I n1987,amemorandumofunderstandingwas signedby13countriestodevelopacommon cellulartelephonesystemacrossEurope. n1989,GSMresponsibilitywas transferredtotheEuropeanTelecommunicationsStandards Institute(ETSI) andphaseI oftheGSMspecificationswerepublishedin1990. ThefirstGSM networkwaslaunchedin1991byRadiolinjainFinlandwithjointtechnical infrastructuremaintenancefromEricsson. Bytheendof1993,overamillionsubscriberswereusingGSMphonenetworksbeing operatedby70carriersacross48countries. GSMStandards ETSI 3GPP Reference: http://www.mobilein.com/gsm_standards.htm http://www.etsi.org/WebSite/homepage.aspx www.3gpp.org/
  4. 4. ElectroMagneticSpectrum
  5. 5. GSMIntroduction www.h2kinfosys.comEmail: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615  GSM 900  GSM 1800  GSM 1900  GSM 450  GSM 480  GSM 850 GSMFrequencyBands
  6. 6. Cellularconcepts ThebasicunitofGSMradio coverageisknownasacell.Cellistheareacoveredby singletransmitter TypesofCells •Macro cells •<35KMS •Antennaabovetheroofs •Micro cells •Antennabelowtheroofs •Picocells •Verysmallcoverage •ExtendedCells •Radiusof maximum120kms •Coastalregion
  7. 7. www.h2kinfosys.comEmail: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 •Cluster •Frequencyreusepattern
  8. 8. •Cell capacityexpansiontechniques •Cellsplitting •Cellsectoring •Frequencyallocation •Multipleaccesstechniques •FDMA •TDMA •CDM A
  9. 9. UplinkandDownlink
  10. 10. CircuitswitchedVs PacketSwitched
  11. 11. GSMIntroduction www.h2kinfosys.comEmail: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 MS BTS BSC MSC GSMInterfaces
  12. 12. www.h2kinfosys.comEmail: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 MS: TheMSconsistsofthephysicalequipmentusedbythesubscriber toaccessaPLMNforoffered telecommunicationservices.Functionally,theMSincludesaMobileTermination (MT)and,depending onthe servicesit cansupport,variousTerminalEquipment(TE),andcombinationsofTE andTerminalAdaptor (TA) functions(theTAactsasagatewaybetweentheTE and theMT)(see Figure5.4).VarioustypesofMS,such asthe vehiclemountedstation,portablestation,orhandheldstation, areused. AnMS hasanumberofidentities including theInternationalMobileEquipmentIdentity(IMEI),theInternational MobileSubscriberIdentity(IMSI),andtheISDNnumber.TheIMSIis storedintheSIM.TheSIMcard containsallthe subscriber- relatedinformationstored ontheuser’ssideoftheradiointerface. IMSI.TheIMSI isassignedtoanMSat subscriptiontime.Ituniquelyidentifiesa givenMS.TheIMSIwillbe transmittedovertheradio interfaceonlyif necessary.TheIMSI contains15digitsand includes •MobileCountryCode(MCC)—3digits(homecountry) •MobileNetworkCode(MNC)—2digits(homeGSMPLMN) •Mobile SubscriberIdentification(MSIN) •NationalMobileSubscriberIdentity(NMSI) IMEI: TheIMEIuniquelyidentifiestheMSequipment.Itisassignedbytheequipmentmanufacturer.TheIMEI contains 15digitsand carries •TheTypeApprovalCode(TAC)—6digits •TheFinalAssemblyCode(FAC)—2digits •Theserialnumber (SN)—6digits •ASpare(SP)—1digit
  13. 13. BSS: TheBSSisthephysicalequipment thatprovidesradiocoverageto prescribed geographicalareas,known as thecells.It containsequipment required to communicatewiththeMS.Functionally,aBSS consistsofacontrol functioncarried out bytheBSC and atransmitting functionperformed by theBTS.TheBTSistheradio transmissionequipment andcoverseachcell.ABSScan serveseveralcells becauseit canhavemultipleBTSs. TheBTScontainstheTranscoderRateAdapterUnit (TRAU).InTRAU,theGSM-specificspeech encoding and decodingiscarriedout, aswellastherateadaptationfunctionfordata.Incertain situationstheTRAUis locatedat theMSC to gainan advantageofmorecompressed transmissionbetweentheBTS and theMSC. NSS: TheNSSincludesthemainswitchingfunctionsof GSM,databasesrequired forthe subscribers,and mobility management.Itsmain role isto managethecommunicationsbetweenGSM and other networkusers. WithintheNSS,the switchingfunctionsareperformed bytheMSC.Subscriberinformationrelevant to provisioningofservicesiskeptintheHLR. TheotherdatabaseintheNSS istheVLR. TheMSCperformsthenecessaryswitchingfunctionsrequiredfortheMSslocatedinan associated geographicalarea,calledanMSC area
  14. 14. GSMIntroduction www.h2kinfosys.comEmail: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 GSMInterfaces TheRadioInterface(MS toBTS) TheUmradio interface(betweenMSand basetransceiverstations[BTS])isthemost importantin anymobile radiosystem, inthat it addressesthedemandingcharacteristicsoftheradio environment. AbisInterface(BTStoBSC) TheinterconnectionbetweentheBTS and theBSC isthroughastandard interface,Abis(mostAbisinterfacesarevendorspecific).Theprimaryfunctions carriedoverthisinterfacearetrafficchanneltransmission,terrestrialchannel management,and radio channelmanagement. AInterface(BSCtoMSC) TheAinterfaceallowsinterconnectionbetweentheBSSradio basesubsystem andtheMSC.ThephysicallayeroftheAinterfaceisa2-Mbps standard Consultative CommitteeonTelephoneandTelegraph (CCITT)digitalconnection.
  15. 15. GSMIntroduction www.h2kinfosys.comEmail: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 SignalingProtocolsbetweenGSMEntities
  16. 16. www.h2kinfosys.comEmail: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 GSMIntroduction GPRSArchitecture
  17. 17. www.h2kinfosys.comEmail: training@h2kinfosys.com USA: 770-777-1269 UK: 020 33717615 GSMIntroduction ComponentsinGPRS GPRSMobileStations: NewMobileStationarerequiredtouse GPRSservices becauseexistingGSMphonesdonothandletheenhancedairinterfaceorpacket data.Avarietyof MScanexist,includingahigh-speedversionof currentphonesto supporthigh-speed dataaccess,anewPDAdevice withanembedded GSMphone,and PC cardsforlaptop computers.Thesemobilestationsarebackward compatibleformakingvoicecalls usingGSM. GPRSBaseStationSubsystem: EachBSCrequires theinstallationof oneormorePacketControlUnits(PCUs) and asoftwareupgrade.The PCU providesaphysicaland logicaldatainterfaceto the basestationsubsystem(BSS)forpacketdata traffic.TheBTScanalsorequireasoftwareupgradebut typicallydoesnotrequirehardwareenhancements. Wheneithervoiceor data trafficisoriginatedat thesubscribermobile,it istransportedovertheairinterface to the BTS,andfromthe BTStotheBSCinthesamewayasastandard GSMcall.However,attheoutputof theBSC,thetrafficisseparated;voiceissentto the mobileswitchingcenter(MSC)perstandardGSM,and dataissentto anewdevicecalledtheSGSN viathe PCU overaFrame Relay interface. GPRSSupportNodes: Followingtwo new components,calledGPRSsupportnodes (GSNs),areadded: GatewayGPRSsupport node(GGSN): TheGateway GPRSSupport Nodeactsasaninterfaceandarouterto externalnetworks.The GGSNcontainsroutinginformationforGPRS mobiles, whichisusedtotunnelpacketsthroughthe IPbasedinternalbackbonetothe correctServing GPRSSupportNode. TheGGSN alsocollectscharginginformationconnectedtotheuseof theexternaldatanetworksandcanactasapacketfilterforincomingtraffic. ServingGPRSsupportnode(SGSN): TheServing GPRSSupport Nodeisresponsibleforauthenticationof GPRSmobiles,registrationofmobilesin thenetwork,mobility management,and collectinginformationforchargingfortheuseoftheair interface. InternalBackbone: Theinternal backboneisanIP based networkused tocarrypacketsbetween differentGSNs.Tunnelingisused betweenSGSNsand GGSNs,sotheinternal backbone doesnotneed anyinformationaboutdomainsoutsidethe GPRSnetwork.SignalingfromaGSNtoaMSC, HLRorEIRisdoneusingSS7.

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