OFDM系統(tǒng)中符號同步和信道估計的研究.pdf

1、學(xué)校代號：10532學(xué)號：S03095007密級：湖南大學(xué)碩士學(xué)位論文OFI)M系統(tǒng)中符號同步和信道估計的研究堂焦由請厶蝰名!金莖筮——————————一昱垣蛙芻區(qū)驅(qū)整：一王鹽熬援—————————一墻羞望焦；魚玉蘭籃星工程堂墮————一童些名煎；電墮生垡塑筮——————————一詮窒握童旦塑12四￡生量月』生且—————一迨窒簦攢旦塑二2鯉生4且』墜且—————一鳘避重雖金主盛!戴煎送熬援————————一OFDM系統(tǒng)中符號潮步耩信邀

2、話詩靜醑究AbstractThefuturewirelessmobilecommunicationsystemsareexpectedtoprovideubiquitous，high—quality，andhigh—ratemobilemultimediatransmissionHowever，hostilemultipathfadingradioconditionsgiverisetoseriousintersymbolinterfe

3、rence(ISI)；evenworse，wirelesschannelareoftentimevarying，whichmakesthesystemmorevulnerableandmoredifficulttotrackthechannelstateOrthogonatFrequencyDvisionMultiplexing《OFDM)，whichisinherentlyresistantagainstISI，hasinvokeda

4、popularresearchinterestinrecentyears，andhasbeenapromisingcandidatetechnologyofthephysicallayerforfutureweidebandhilgh—date—ratewirelesscommunicationsNOtwithstanding，OFDMismuchmorevulnerabletoerrorsofbothtimeandfrequencys

5、ynchronizationandtothatofchannelestimation，andhowtoobtaincorrecttimingandchannetestimationefficientlyishighlycriticaltoOFDMsystemsThedissertationwillfocusonbothoftheaspectsofOFDMsystemsmentionedaboveFirstly，inthisdissert

6、ationtwotypesofsymbolstarttimeestimationschemesforOrthogonalFrequencyDivisionMultiplexing(OFDM)systemsareevaluatedandanalyzedSimulationresultssuggestthat：pilotsymbolbasedsynchronizationhasbetterperformanceovercyclicprefi

7、xbasedschemes，anditperformancesimprovedwhenthelengthofpilotsymbolincreases；cyclicprefixbasedsynchronizationmethodhasahighspectrumefficiencyinspiteofitsrelativelowacquisitionofsynchronizationrate；andtheformerismoresuitabl

8、etoburstingsymbolbasedinformationsystems，suchasIEEE8021la，whilethelaterCanbeusedinbroadcastingsystemsforcontinuousmediastreams，suchasdigitalvideobroadcastingsystems，digitalaudiobroadcastingsystemsSecondly，thedissertation

9、proposesanovelblindsymboltimingschemeforOFDMsystemsbasedoncyclostationarityfeatureofreceivedsymbolsTheproposedschemesalsoexploitstheperiodicityofOFDMsymbolintroducedbycyclicprefix，byapplying2一dimentionalFouriertransforma

10、tionandchoosingtheappropriatecorrelationpeakvalueasthesymbolstartlocation，theprecisionofthisschemeishi馥erthanpreviousconventionalmethodThirdly，thedissertationpresentsanalysiswithregardtochannelestimationofOFDMsystemsSeve

11、ralinterpolationalgorithminOFDMsystemswhichbasedonpilotsequencehavebeenanalyzedinthefirstinstance，andtheinfluenceofthechannelnoiseoninterpolationprecisionhasdiscussed。Thetheoreticanalysisandsimulationresultsshowthat：thei