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1、ABSTRACTABSTRACTAsoneofthekeytechnologiesofwirelesscommunicationsystems,MultipleInputMultipleOutput(MIMO)provideshighsystemcapacityandrobustness.TherearethreemaintechniquesusedinMIMOtransmissionsystems:spatialdiversity,spatialmultiplexingandspatialmodu
2、lation.Sincetheyhavetheirownadvantages,thesetechniqueswillbeadaptedtodifferenttransmissionenvironment.Spatialdiversitytechniqueismainlyusedtoovercometheimpactofwirelesschannelfading.Spaceandtimedimensionsarejointlycodedtosendmultiplecopiesofadatastream
3、.Atthereceiver,multi-pathgaincanbeobtainedandthesystemperformancecanbeimproved.Basedonspacetimecoding,thisthesiswilldoresearchondistributedantennasystemandspacetimeblockcodedspatialmodulationsysteminordertoobtainahigherdatatransmitrate.Infirstchapter,t
4、hedevelopmentprocessofwirelesscommunicationswillbeoverviewed.ThecurrentresearchstatusofdownlinkcommonMIMOtechniquesandspacetimecodingwillbeintroduced.Inthesecondchapter,thesystemmodelandmathematicalmodelofthreecommonMIMOtransmissiontechniques,spacedive
5、rsity,spacemultiplexingandspatialmodulation,willbesummarized.Tobespecific,differentdimensionspacetimeblockcodes(STBCs)willbeintroducedandsimulated.Theadvantagesandshortagesofthesetechniqueswillbeanalyzedandsimulated.Inthethirdchapter,thesystemmodelappl
6、iedinthischapterwillbefirstlyintroduced.Then,theeffectofRayleighfadingandDopplerspreadwillbesummarized.Pilotsymbolassistedmodulationandrecursiveleastsquaresalgorithmwillbeappliedinthesystemofchapter3.Furthermore,distributedantennasystemandcentralizedan
7、tennasystemwillbecomparedandsimulated.TheMatlabsimulationresultsshowthatdistributedantennasystemcanobtainhigherstabilitythancentralizedantennasystem.Moreover,whencomparingthebetterperformanceofdistributedantennasystemandcentralizedantennasysteminonecel
8、l,theareaofdistributedantennasystemisbiggerthanthatofthecentralizedantennasystem.Chapter4isthemostimportantpartofthethesis.AnewspacetimeblockcodedIIIABSTRACTspatialmodulation(STBC-SM)technique,whichcombinedspacetimeblockcodeandspatialmo
