南邮无线通信原理第一章

2020/3/31CourseIntroduction2020/3/32•WirelessCommunicationsPrinciples•32classhoursinall•ExaminationpaperisinEnglish•Referencebooks2020/3/33Contents1.IntroductiontoWirelessCommunicationSystems(ch.1,ch.2)2.TheCellularConcept:SystemDesignFundamentals(ch.3)3.MobileRadioPropagation:Large-ScalePathLoss(ch.4)4.MobileRadioPropagation:Small-ScaleFadingandMultipath(ch.5)5.MultipleAccessTechniquesforWirelessCommunications(ch.9)2020/3/34IntroductiontoWirelessCommunicationSystems2020/3/35WhatiswirelesscommunicationAnyformofcommunicationthatdoesnotrequirethetransmitterandreceivertobeinphysicalcontactElectromagneticwavepropagatedthroughfree-spaceShortwave,Microwave,IR,Optical2020/3/36Lightofsightpropagation;Skywavepropagation;Groundwavepropagation.Themodeofpropagationofelectromagneticwaves2020/3/37Ataglanceofthehistory1894-96FirstTransmitter–FirstPatent1897World’sFirstWirelessTelegraph&SignalCompany1901Telegraphacrosstheatlanticocean1899-1912SavingLives1920Discoveryofshortwave(100m)GuglielmoMarconi2020/3/38Thosewhohadbeensaved,hadbeensavedthroughoneman,Mr.Marconi...andhismarvellousinventionTitanic2020/3/39Historyofwirelesscommunication1920’s:Radiobroadcastingbecamepopular1920’s:MobilereceiversinstalledinpolicecarsinDetroit1928:manyTVbroadcasttrials1930’s:TVbroadcastingdevelopment1950’s:Communicationssatelliteslaunched1960’s:BellLabsdevelopedcellularconceptLate1970’s:technologyadvancesenableaffordablecellulartelephone1974-1978:Firstfieldtrialforcellularsystem2020/3/310CellularSystemsSatelliteSystemsWirelessLANWirelessMANWirelessPANCurrentWirelessSystems2020/3/311WirelessCommunicationsSystemDefinitions(p10)•Controlchannel:vitalforinitiating,requesting,orpagingacall•Trafficchannel(voicechannel):dedicatedtocarryingrevenue-generatingtraffic.•Simplex•Half-duplexCommunicationsystemswhichallowtwo-waycommunicationbyusingthesameradiochannel•Full-duplexCommunicationsystemswhichallowsimultaneoustwo-waycommunication.•FDD•TDDisonlypossiblewithdigitaltransmissionformatsanddigitalmodulation,andisverysensitivetotiming•MSC2020/3/312•Thedisadvantageofasingletransmitteronacentral•ThebigbreakthroughcamewhenAT&TLabsresearchersdividedwirelesscommunicationsintoaseriesofcellsTheproposalofcellularconceptBASESTATION2020/3/313Firstgenerationofmobiletechnology•Analogcellularsystems(FM)•Onlycarryvoicetraffic•LesssecureandpronetointerferencewhensignalisweakIncludestandardsAMPS30KHzFMFDMATACS25KHzFMFDMA2020/3/3142ndgenerationofmobiletechnology•Digitalcellularsystems•Supportinghighbitratevoice,limiteddatacommunication•ImprovedqualityIncludestandardsGSM200KHzGMSKTDMA(Byfarthedominantoneinchina)IS-951.23MHz2020/3/315Offersenhancementstocurrentapplicationsincludinggreaterdataspeeds,increasedcapacityforvoiceanddataandabroaderrangeofservicesCDMA2000WCDMATD_SCDMAHighestdatarate(3G)–atleast144Kb/sinavehicularenvironment,–384Kb/sinapedestrianenvironment,–2048Kb/sinanindoorofficeenvironment.3G2020/3/316WLANsconnect“local”computers(100mrange)BreaksdataintopacketsChannelaccessisshared(randomaccess)BackboneInternetprovidesbest-effortserviceISMbandsWirelessLANStandards:Wi-Fi802.11b,802.11a,802.11gWirelessLocalAreaNetworks(WLANs)2020/3/317WLANInfrustructure2020/3/318WLANapplications2020/3/319CablereplacementRFtechnology(lowcost)Shortrange(10m,extendableto100m)2.4GHzband(crowded)1Data(700Kbps)and3voicechannelsWidelysupportedbytelecommunications,PC,andconsumerelectronicscompanies802.15.1Bluetooth802.15.3UltraWidebandRadio(UWB)WPAN2020/3/320Adhocnetworks2020/3/3212020/3/322•WirelessInternetconnectionofhotspots•High-speedInternetaccessformobileusers•DSLreplacement•WirelessbackboneIEEE802.16(BroadbandWirelessAccess,BWA)IEEE802.20(MobileBroadbandWirelessAccess,MBWA)WirelessMetropolitanAreaNetwork(WMAN)2020/3/323Networkstructure2020/3/324Trendsinwirelesscommunications•AllIPbased(IPv6)(Packetswitched)•Flexibleplatformofcomplementaryaccesssystems(Combinationofdifferentwirelessaccesssystems))•Highersystemcapacity(Users/Service,5-10timeshigherthan3G)•HigherTransmissionDatarate•Higherfrequencyefficiency•Moreadvancedmultimediaapplications•ImprovedQoS•Realizehighlevelsofsecurityandauthentication•Globalcoverage&Globalroaming2020/3/325GoalofMobilecommunicationPersonalCommunicationSystem(PCS)WhoeverWheneverWhereverWhomeverWhatever2020/3/326AllIPbased:统一的IP核心网2020/3/327FeaturesofWirelessCommunications•InformationistransmittedbyradiowavesRadiochannelisnotagoodtransmissionchannel:–Largepathloss,–Multipath,–Time-variant(SignalFading)•IncomplexinterferenceenvironmentInterferencesfrom–Space(cosmic,atmospherephenomenon)–Industryequipment–Otherelectronicandcommunicationsystems–Themselves2020/3/328FeaturesofWirelessCommunicationsLimitedradiospectrum,butthedemandisincreasingIncreasingUsernumber,increasingservicesdemandcallfor:IncreasingspectrumefficiencyofsystemsReasonablespectrumallocationVarietyofNetworks,complexnetworkmanagementMobilitymanagement(switching,roaming)Securitymanagement(Registration,authentication,accountingetc.)Mobilestationsaresuitabl