无线移动互联网：原理、技术与应用 教学课件 作者 崔勇 CH2 AP Association.ppt

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1、WirelessAccessTechnologyCS80240333Instructor:CUIYong1OutlineIntroductionIEEE802familystandards802.11(WiFi)802.15(Bluetooth,UWB)802.16(WiMax)802.20802.22Cellularnetworkstandards3G4G22Wireless?WirelessnetworkisanetworkthatusesradiowavesasitscarrierThelastlinkwiththeusersiswire

2、less,togiveanetworkconnectiontoallusersinabuildingorcampusThebackbonenetworkusuallyusescables3Wirelessbuildings4HistoryofwirelesscommunicationGuglielmoMarconiinventedthewirelesstelegraphin1896CommunicationbyencodingalphanumericcharactersinanalogsignalSenttelegraphicsignalsac

3、rosstheAtlanticOcean1914–firstvoicecommunicationoverradiowavesCommunicationssatelliteslaunchedin1960sAdvancesinwirelesstechnologyRadio,television,mobiletelephone,communicationsatellitesMorerecentlySatellitecommunications,wirelessnetworking,cellulartechnology5ReasonsforWirele

4、ssNetworksMobilecommunicationisneededCommunicationmusttakeplaceinaterrainthatmakeswiredcommunicationdifficultorimpossibleAcommunicationsystemmustbedeployedquicklyCommunicationfacilitiesmustbeinstalledatlowinitialcostThesameinformationmustbebroadcasttomanylocations6Typesofwir

5、elesscommunicationcelullarwirelesscomputernetworkradioservice7Wirelessapplications8ProblemswithWirelessNetworksOperatesinalesscontrolledenvironment,soismoresusceptibletointerference,signalloss,noise,andeavesdroppingGenerally,wirelessfacilitieshavelowerdataratesthanguidedfaci

6、litiesFrequenciescanbemoreeasilyreusedwithguidedmediathanwithwirelessmedia9Howtousewirelessnetwork?Tosolvetheproblemsabove,wehavemadeallkindsofstandardsforwirelessnetworkIEEE802familystandards802.1xCellularnetworkstandards3G、4G10OutlineIntroductionIEEE802familystandards802.1

7、1(WiFi)802.15(Bluetooth,UWB)802.16(WiMax)802.20802.22Cellularnetworkstandards3G4G1111IEEE802familystandardsDealingwithlocalareanetworkandmetropolitanareanetworkRestrictedtonetworkscarryingvariable-sizepacketsSpecifiedinIEEE802maptothelowertwolayersDatalinklayerLLCsublayerMAC

8、sublayerPhysicallayer12IEEE802familystandards13IEEE802.22RAN“RegionalAreaNe