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1、河南科技大学本科毕业设计论文翻译原稿ASurveyonMobileWiMAXBoLi,HongKongUniversityofScienceandTechnologyYangQinandChorPingLow,NanyangTechnologicalUniversityChoonLimGwee,RepublicPolytechnicABSTRACTTheIEEE802.16standard,commonlyknownasWiMAX,isthelatesttechnologythathaspromisedtoofferbr
2、oadbandwirelessaccessoverlongdistance.Since2001WiMAXhasevolvedfrom802.16to802.16dforfixedwirelessaccess,andtothenewIEEE802.16estandardwithmobilitysupport.Inthisarticleweprovideanoverviewofthestate-of-the-artmobileWiMAXtechnologyanditsdevelopment.WemobileWiMAXspec
3、ification.INTRODUCTIONIEEE802.16,asolutiontobroadbandwirelessaccess(BWA)commonlyknownasWorldw-ideInteroperabilityforMicrowaveAccess(WiMAX),isarecentwirelessbroad-bandstanda-rdthathaspromisedhighbandwidthoverlongran-getransmission.Thestandardspecifiestheairinterfa
4、ce,includingthemediumaccesscontrol(MAC)andphysical(PHY)layers,ofBWA.Thekeydev-elopmentinthePHYlayerincludesorthogonalfre-multipleaccessisachi-evedbyassigningasubsetofsubcarrierstoeachindividualuser.Thisres-emblescode-divisionmultipleaccess(CDMA)spreadspectruminth
5、atitcanprovidedifferentqualityofservice(QoS)foreachuser;usersachievedifferentdataratesbyas-signingdifferentcodespreadingfactorsordifferentnumbersofspreadingcodes.InanOFDMsystem,thedataisdividedintomultipleparallelsubstreamsatatransmittedonaseparateorthogonalsubca
6、rrier.Thisincreasessymboldurationandimprovessystemrobustness.OFDMisachievedbyprovidingmultiplexingonusers’datastreamsonbothuplinkanddownlinktransmissions.Firstpublishedin2001,theIEEE802.16standardspecifiedafrequencyrangeof10–6629河南科技大学本科毕业设计论文GHzwithatheoreticalm
7、aximumbandwidthof120Mb/sandmaximumtransmissionrangeof50line-of-sight(LOS)transmissionandthusdoesnotseemtofavordeploymentinurbanareas.Avariantofthestandard,IEEE802.16a-2003,approvedinApril2003,cansupportnon-LOS(NLOS)transmissionandadoptsOFDMatthePHYlayer.Italsoadd
8、ssupportforthe2–11earlierdraftofIEEE802.16isthatitcoverstoomanyprofilesandPHYlayers,whichcanleadtopotentialinteroperabilityproblems[1].Thishasbeenlargelyrecogn
