實用文檔ThedevelopmenttrendofmodernmobilecommunicationABSTRACTRecallingthedevelopmenthistoryofthemobilecommunication,developmentofmobilecommunicationshasgonethroughseveralstagesofdevelopment.Thefirstgenerationofmobilecommunicationtechnologymainlyrefersanalogcellularmobilecommunication,technicalcharacteristicsofacellularnetworkarchitecturetoovercomethelargedistrictsystemcapacityislow,theproblemoflimitedrangeofactivities.Thesecondgenerationmobilecommunicationsisacellulardigitalmobilecommunication,thecellularsystemcanbeprovidedwithdigitaltransmissionandvariousadvantagesofintegratedservices.Thethirdgenerationmobilecommunicationsalsoknownasmodernmobilecommunications.Itisinadditiontothemainfeaturesofasecond-generationmobilecommunicationsystemshavevariousadvantagesandovercomeitsshortcomings,butalsoabletoprovidebroadbandmultimediaservices,canprovidehigh-qualityvideobroadbandmultimediaintegratedservices,andtoachieveglobalroaming.Thirdgenerationtechnologyisnottoosuccessfultoday,butithasgreatprospectsfordevelopment.Solet'stalkaboutdevelopmenttrendofmodernmobilecommunication.Intheinformationtechnologysupport,marketcompetitionanddemandtogether,thedevelopmentofmobilecommunicationtechnologyisleapsandbounds,showingthefollowingmajortrends:Networktrafficdata,packet;broadbandnetworktechnologies;intelligentnetworktechnology;higherfrequencybands;moreeffectiveuseoffrequencies;variousnetworkstoconverge.Understandandmasterthesetrendsonmobileoperatorsandequipmentmanufacturershaveimportantpracticalsignificance.Networktrafficdata,packetMobilewirelessdatacommunicationsareconsideredthemaindirectionofdevelopment.Inrecentyearstherearemainlytwokindsofmobiledatacommunications,oneiscircuit-switchedmobiledataservices,theotherispacket-switchedmobiledataindustry.Wirelessdataservicesisthemaindrivingforceoftheuser'sapplication,andotherareasofcommunication,wirelessdataservicesoneofthemostimportantdrivingforcefromtheInternet.Questforvoicecommunicationanytime,anywheremobilecommunicationssuccesssoearly.Mobilecommunicationsbusinessvalueandusermarkethasbeenprovedthattheglobalmobilemarketwithextraordinarypace.Thenextphaseoftheevolutionofmobilecommunicationsistoprovidemobilemultimediawirelessdatatransferandevenindividuals,thisprogresshasalreadybegun,andwillbeanimportantfuturegrowth.Personalmobilemultimediawillprovidepeoplebasedonlocationcannotimagine,perfectserviceandwirelesspersonalinformationwillpeopleworkandallaspectsoflifeimpact.BroadbandnetworktechnologiesInthehistoryofthetelecommunicationsindustry,mobilecommunicationstechnologyandthemarketmaybethefastestgrowingareas.Business,technologyandmarketinteractionamongarelationship,alongwiththeuserdataandmultimediaservicesdemandincreases,thedatanetworkservice,packetdevelopmentofbroadbandmobilenetworkswillinevitablymovetoward.Thethird-generationmobilesystems,namelyIMT-2000,isatruebroadbandmultimediasystemthatcanprovidehigh-qualitybroadbandintegratedservicesandachieveseamlessglobalcoverage.After2000,thenarrow-bandmobilephonebusinessneedswillremainlarge,butwiththeInternetandotherhigh-speeddatacommunicationsandmultimediacommunicationsdemand-driven,integratedbroadbandmultimediaserviceswillgraduallyincrease,andtheconstructionofthefutureinformationsuperhighwayseamlesscoverageintermsof,broadbandmobilecommunicationsasawhole,asubsetofthemobilemarketsharewillbecomeincreasinglyimportant.3.IntelligentnetworktechnologyGrowingdemandformobilecommunicationsandnewtechnologiesinmobilecommunicationwidelyused,promptingthemobilenetworkhasbeendevelopingrapidly.Mobilenetworkconsistssimplytransferandexchangeofinformation,andgraduallytostoreandprocessinformation,thedevelopmentofintelligent,mobileintelligentnetworkasaresult.Alongwiththemobilenetworkevolutiontothirdgenerationsystems,intelligentnetworksareconstantlyimproved.IntelligentNetworkanditsintelligenceservicesconstitutethebasicconditionsforfuturepersonalcommunications.HigherfrequencybandsFromthefirstgenerationanalogmobilephone,tothesecondgenerationofdigitalmobilenetworks,tothefutureofthethirdgenerationmobilecommunicationsystems,networksusingwirelessspectrumfromlowtohightofollowatrend.Bornin1981,thefirstinternationalroamingNMTanalogsystemsusefrequencyband450MHz,1986年NMTchangestothe900MHzband.China'scurrentbandanalogTACSsystemisusedfor900MHz.Inthesecondgenerationnetworks,GSMsystemsusefrequencybandisstarted900MHz,IS-95CDMAsystemis800MHz.InordertoFromthefundamentallyimprovetheGSMsystemthecapacityofthe,1997appearedin1800MHzsystem,GSM900/1800dual-bandnetworkrapidpopularization.2002willbeputintocommercialthirdgenerationsystemsIMT-2000ispositionedinthe2GHzband.5.MoreeffectiveuseoffrequenciesRadiofrequencyisavaluableresource.Withtherapiddevelopmentofmobilecommunications,spectrumresourcesarelimitedandthedramaticincreaseinmobilesubscribersincreasinglyacutecontradictions,a"frequencyofsevereshortage"phenomenon.Frequencycongestionproblemsolvingwayistousevariousfrequencyeffectiveuseoftechnologyanddevelopmentofnewbands.AsthefuturemainstreamofthethirdgenerationmobilecommunicationsystemswirelessaccesstechnologyWCDMA(WidebandCodeDivisionMultipleAccess)tomoreefficientuseofradiofrequencies.Ituseshierarchicalcellstructure,adaptiveantennaarrayandcoherentdemodulation(bidirectional)technology,asubstantialincreaseinnetworkcapacityavailablethatcanbettermeettherequirementsofthedevelopmentoffuturemobilecommunication.6.VariousnetworkstoconvergeTechnologicaldevelopments,changesinmarketdemand,marketcompetitionandmarketcontrolpolicieswillrelaxcomputernetworks,telecommunicationne