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1、Chapter16WirelessWANs: CellularTelephoneandSatelliteNetworksCopyright©TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.116-1CELLULARTELEPHONYCellulartelephonyisdesignedtoprovidecommunicationsbetweentwomovingunits,calledmobilesta
2、tions(MSs),orbetweenonemobileunitandonestationaryunit,oftencalledalandunit.Frequency-ReusePrincipleTransmittingReceivingRoamingFirstGenerationSecondGenerationThirdGenerationTopicsdiscussedinthissection:2Figure16.1Cellularsystem3Figure16.2Frequencyreu
3、sepatterns4AMPSisananalogcellularphonesystemusingFDMA.Note5Figure16.3CellularbandsforAMPS6Figure16.4AMPSreversecommunicationband7Figure16.5Second-generationcellularphonesystems8Figure16.6D-AMPS9D-AMPS,orIS-136,isadigitalcellularphonesystemusingTDMAan
4、dFDMA.Note10Figure16.7GSMbands11Figure16.8GSM12Figure16.9Multiframecomponents13GSMisadigitalcellularphonesystemusingTDMAandFDMA.Note14Figure16.10IS-95forwardtransmission15Figure16.11IS-95reversetransmission16IS-95isadigitalcellularphonesystemusingCDM
5、A/DSSSandFDMA.Note17Themaingoalofthird-generationcellulartelephonyistoprovideuniversalpersonalcommunication.Note18Figure16.12IMT-2000radiointerfaces1916-2SATELLITENETWORKSAsatellitenetworkisacombinationofnodes,someofwhicharesatellites,thatprovidescom
6、municationfromonepointontheEarthtoanother.Anodeinthenetworkcanbeasatellite,anEarthstation,oranend-userterminalortelephone.OrbitsFootprintThreeCategoriesofSatellitesGEOSatellitesMEOSatellitesLEOSatellitesTopicsdiscussedinthissection:20Figure16.13Satel
7、liteorbits21WhatistheperiodoftheMoon,accordingtoKepler’slaw?Example16.1HereCisaconstantapproximatelyequalto1/100.Theperiodisinsecondsandthedistanceinkilometers.22Example16.1(continued)SolutionTheMoonislocatedapproximately384,000kmabovetheEarth.Therad
8、iusoftheEarthis6378km.Applyingtheformula,weget.23AccordingtoKepler’slaw,whatistheperiodofasatellitethatislocatedatanorbitapproximately35,786kmabovetheEarth?Example16.2SolutionApplyingtheformula,weget24Thismeansthatasatellitelocatedat35,786kmhasaperio
