ieee802.11ac协议与宽带mimo-ofdm技术的分析

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1、ABSTRACTWiththedemandforhigh—speedwirelessInternetaccess，IEEEcommitteehasbeguntodevelopanewversionofthewirelessLANstandardnamedIEEE802．1lac．ThisstandardisnotonlyfullycompatiblewiththeIEEES02．1lnstandardwhichhasthehi曲estavailabletransmissionrateanditsupportsthemax

2、imumtransferrateupto1Gbps．AstheotherstandardsofWLANseries，IEEES02．1lacstandardfocusesonthephysicallayerandMAClayertransmissiontechnologyaccesstechnology．Inthephysicallayer,itisthefirsttimethat802．1lacstandardbringthemulti—userMIMOtechnologyintotheWLANsystem．Witht

3、histechnology,802．1lacsimultaneouslytransmitdatatOmorethanoneuseratthesametime．802．1lacsystemsupports2．4GHzand5GHzwithmanydifferentbandwidthandincreasesthemaximummodulationandcodingrate，whichgreatlyimprovedphysicallayertransmissionrate．Inordertosupportthemulti—us

4、erMIMOtechnologiesofthephysicallayer,802．1lacprovidesusersgroupschedulinganduserchannelfeedbackmechanismintheMAClayer．ThekeyofPhysicallayermulti--userMIMOtechnologyismulti--userprecedingusingtheuser'schannelinformation．Theprecedingmethoddirectlyaffectsthemutualin

5、terferencebetweenusers．IEEE802．1lacsystemonlysupportalimitedchannelinformationfeedback，therefore，howtodesignaprecedingmethodwiththelimitedchannelinformationistheactualproblemtobesolved．Bothprecedingdesignmethodologyanduserthecorrelationofchannelinformationeffectp

6、erformanceofMulti-USerpreceding．Consideringusergroupstrategyinthestandard,selectingtheappropriateusersforprecedingCanimprovethepre—codingperformance，whichincreasethesystemtransmissionrate．Inthispaper,themainresearchworkareasfollows：1．ThesecondchapterfocusonIEEE80

7、2．1lacindoorwirelesschannelmodel．consideringthewiderchannelbandwidthandmulti-user,physicallayersynchronizationispresentbasedonstandardphysicallayerpreamblesequence．2．somecommonsingle-userMIMOtechnologiesispresentinchapterthree，includingspace-timecodingandsingle—u

8、serbeamforming．3．Thechapterthreealsofocusonthecompressedchannelfeedbackmechanismsofthestandard．Linkadaptationtechniquesandreversedirectionprotocolimprovementsa