英文版01 无线通信简介课件.ppt

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1、Chapter1:Introduction1Computersforthenextdecades?Computersareintegrated,andtechnologyisinthebackgroundsmall,cheap,portable,replaceable-nomoreseparatedevicescomputerrecognizetheenvironmentoftheuserandreactappropriate(“locationawareness,contextawareness”)Ad

2、vancesinmobilewirelesstechnologymorecomputingpowerinsmallerdeviceslowpowerconsumptionmorebandwidthoverlappedcoveragemultipleinterfaces:wirelessLANs,wirelessWANs,wirelessPANs(“ubiquitous,convergence”)2MobilecommunicationTwoaspectsofmobility:usermobility:us

3、erscommunicate(wireless)“anytime,anywhere,withanyone”deviceportability:devicescanbeconnectedanytime,anywheretothenetworkWirelessvs.mobileExamplesstationarycomputernotebookinahotelwirelessLANsinhistoricbuildingsPersonalDigitalAssistant(PDA)Thedeman

4、dformobilecommunicationcreatestheneedforintegrationofwirelessnetworksintoexistingfixednetworks:localareanetworks:standardizationofIEEE802.11,ETSI(HIPERLAN)Internet:MobileIPextensionoftheinternetprotocolIPwideareanetworks:e.g.,3Gdataservice3ApplicationsIV

5、ehiclestransmissionofnews,roadcondition,weather,musicpersonalcommunicationpositionviaGPSlocalad-hocnetworkwithvehiclesclose-bytopreventaccidents,guidancesystem,redundancyEmergenciesearlytransmissionofpatientdatatothehospital,currentstatus,firstdiagnosisre

6、placementofafixedinfrastructureincaseofearthquakes,hurricanes,fireetc.crisis,war,...4Typicalapplication:roadtrafficadhocUMTS,WLAN,DAB,DVB,GSM,cdma2000,TETRA,...PersonalTravelAssistant,PDA,Laptop,GSM,UMTS,WLAN,Bluetooth,...5Mobileandwirelessservices–Always

7、BestConnectedUMTS2Mbit/sUMTS,GSM384kbit/sLAN100Mbit/s,WLAN54Mbit/sUMTS,GSM115kbit/sGSM115kbit/s,WLAN11Mbit/sGSM/GPRS53kbit/sBluetooth500kbit/sGSM/EDGE384kbit/s,DSL/WLAN3Mbit/sDSL/WLAN3Mbit/s6ApplicationsIITravelingsalesmendirectaccesstocustomerfilesstored

8、inacentrallocationconsistentdatabasesforallagentsmobileofficeReplacementoffixednetworksremotesensors,e.g.,weather,earthactivities,buildingsafetyflexibilityfortradeshowsLANsinhistoricbuildingsEntertainment,education,