无线通信原理与应用第一章

2020/4/171WirelessCommunicationsPrinciplesChapter1:Introduction(Referencebook:TheodoreS.Rappaport)[e-mail]2020/4/172CourseInformation•32classhoursinall•ExaminationpaperisinEnglish•Referencebooks:•TheodoreS.Rappaport.WirelessCommunicationsPrinciplesandPractice(2ndEdition).电子工业出版社，2004年版•TheodoreS.Rappaport著，周文安等译.无线通信原理与应用.电子工业出版社，2006年版2020/4/173Maincontentsinthecoursewithin32hours•IntroductiontoWirelessCommunicationSystems(ch.1,ch.2,selectedch11)•TheCellularConcept:SystemDesignFundamentals(ch.3)•MobileRadioPropagation:Large-ScalePathLoss(ch.4)•MobileRadioPropagation:Small-ScaleFadingandMultipath(ch.5)•MultipleAccessTechniquesforWirelessCommunications(ch.9)2020/4/174Wirelesscommunication:thetransferofinformationoveradistancewithouttheuseofelectricalconductorsorwires.CommunicationviacomputersthatreliesonradiosignalsTheequationrelatedtothespeedoflight：Thespeedoflight;carrierfrequency;wavelength;CfVCfV1.1Adefinitionofwirelesscommunication2020/4/175Lightofsightpropagation;Skywavepropagation;Groundwavepropagation.Themodesofradiowavepropagation2020/4/176Ataglanceofthehistory1894-96FirstTransmitter–FirstPatent1897World’sFirstWirelessTelegraph&SignalCompany1901Telegraphacrosstheatlanticocean1899-1912SavingLives1920Discoveryofshortwave(100m)GuglielmoMarconi2020/4/177Historyofwirelesscommunication1920’s:Radiobroadcastingbecamepopular1920’s:MobilereceiversinstalledinpolicecarsinDetroit1928:manyTVbroadcasttrials1930’s:TVbroadcastingdevelopment1950’s:Communicationssatelliteslaunched1960’s:BellLabsdevelopedcellularconceptLate1970’s:technologyadvancesenableaffordablecellulartelephone1974-1978:Firstfieldtrialforcellularsystem2020/4/178CellularSystemsSatelliteSystemsWirelessLANWirelessMANWirelessPAN1.2CurrentWirelessSystems2020/4/179WirelessCommunicationsSystemDefinitions(pp:10)•BaseStation•Controlchannel:vitalforinitiating,requesting,orpagingacall•Forwardchannel:fromBStothemobile(alsoSubscriber)•Reversechannel:fromthemobiletoBS•Half-duplexsystemsallowingtwo-waycommunicationbyusingthesameradiochannel•Full-duplexsystemsallowingsimultaneoustwo-waycommunication.•Handoff•Mobilestation•MSC:MobileSwitchingCenter•Simplexsystemandetal.2020/4/1710•Thedisadvantageofasingletransmitteronacentral•ThebigbreakthroughcamewhenAT&TLabsresearchersdividedwirelesscommunicationsintoaseriesofcellsTheproposalofcellularconceptBASESTATION2020/4/1711Firstgenerationofmobiletechnology•Analogcellularsystems(FM)•Onlycarryvoicetraffic•LesssecureandpronetointerferencewhensignalisweakIncludestandardsAMPS30KHzFMFDMATACS25KHzFMFDMA1.3Mobilecommunicationnetworks2020/4/17122ndgenerationofmobiletechnologyOr2GCellularNetworks(Hereafter)•Digitalcellularsystems•Supportinghighbitratevoice,limiteddatacommunication•ImprovedqualityIncludestandardsGSM200KHzGMSKTDMA(Byfarthedominantoneinchina)IS-951.23MHz2020/4/1713Offersenhancementstocurrentapplicationsincludinggreaterdataspeeds,increasedcapacityforvoiceanddataandabroaderrangeofservicesCDMA2000WCDMATD_SCDMAHighestdatarate(3G)–atleast144Kb/sinavehicularenvironment,–384Kb/sinapedestrianenvironment,–2048Kb/sinanindoorofficeenvironment.3G2020/4/1714WLANsconnect“local”computers(100mrange)BreaksdataintopacketsChannelaccessisshared(randomaccess)BackboneInternetprovidesbest-effortserviceISMbandsWirelessLANStandards:Wi-Fi802.11b,802.11a,802.11g1.4WirelessLocalAreaNetworks(WLANs)2020/4/1715WLANInfrastructure2020/4/1716WLANapplications2020/4/1717802.15.1BluetoothCablereplacementRFtechnology(lowcost)Shortrange(10m,extendableto100m)2.4GHzband(crowded)1Data(700Kbps)and3voicechannelsWidelysupportedbytelecommunications,PC,andconsumerelectronicscompanies802.15.3UltraWidebandRadio(UWB)WPAN1.5WPANandWMAN2020/4/1718Adhocnetworks“removingthewire”2020/4/17192020/4/1720•WirelessInternetconnectionofhotspots•High-speedInternetaccessformobileusers•DSLreplacement•WirelessbackboneIEEE802.16(BroadbandWirelessAccess,BWA)IEEE802.20(MobileBroadbandWirelessAccess,MBWA)WirelessMetropolitanAreaNetwork(WMAN)2020/4/1721Networkstructure2020/4/1722•AllIPbased(IPv6)(Packetswitched)•Flexibleplatformofcomplementaryaccesssystems(Combinationofdifferentwirelessaccesssystems)•Highersystemcapacity(Users/Service,5-10timeshigherthan3G)•HigherTransmissionDatarate•Higherfrequencyefficiency•Moreadvancedmultimediaapplications•ImprovedQoS•Realizehighlevelsofsecurityandauthentication•Globalcoverage&Globalroaming1.6Trendsinwirelesscommunications2020/4/1723GototheallIPbasednetwork2020/4/1724GoalofwirelesscommunicationPersonalCommunicationSystem(PCS)WhoeverWheneverWhereverWhomeverWhatever2020/4/1725FeaturesofWirelessCommunications(A)•InformationistransmittedbyradiowavesRadiochannelisnotagoodtransmissionchannel:–Largepathloss,–Multipath,–Time-variant(SignalFading)•IncomplexinterferenceenvironmentInterferencesfrom–Space(cosmic,atmospherephenomenon)–Industryequipment–Otherelectronicandcommunicationsystems–Themselves2020/4/1726FeaturesofWirelessCommunications(B)Limitedradiospectrum,butthedemandisincreasingIncreasingUsernumber,increa