WiMAX系統(tǒng)中CTC編譯碼器算法分析與方案設計.pdf

1、電子科技大學碩士學位論文WiMAX系統(tǒng)中CTC編譯碼器算法分析與方案設計姓名：張子翔申請學位級別：碩士專業(yè)：通信與信息系統(tǒng)指導教師：彭啟琮20100601ABSTRACTABSTRACTAsacrucialsub—systeminwirelesscommunicationsystem，errorcorrectingcodesimpactmarkedlyontheoverallperformanceofcommunicationsyste

2、mRecognizedaSanoptionalchannelcodingtechnologyinWorldwideInteroperabilityforMicrowaveAccess(WiMAX)standard，theConvolutionalTurboCode(CTC)，whichconcatenatesseveralconvolutionalconstituentencodersinparallel，hasmanyadvantag

3、essuch嬲flexiblecodeword，largerangefordatablocksizes，varyingcodingratesandSOonAsaresultofthecharacteristicsapproximatingthoseofthepseudorandomcode，CTCisabletoprovideperformanceveryneartoShannoncapacityAtthesametime，CTChaS

4、astrongabilitytofightthechannelfadingandvariousinterferingeffect，whichmakesitcapabletoperformsatisfactorilyeveninveryadversecommunicationenvironmentSuchsuperbperformanceattractsenormousinterestfromresearchersallOVerthewo

5、rldImplementationofCTCcodecinWiMAXsystemhasbeenconductedandpresentedCombinedwithclaSsicturbocode，CTCencoderinIEEE80216estandardhasbeenintroduced，andthecorrespondingmodificationinstructuretothatoftheclassicturbocodehasbee

6、nanalyzedPrincipleofCTCdecodingthatadoptsiterativedecodingschemebetweentwoconstituentdecodershasbeenanalyzedOnthebasisofViterbiAlgorithmandSOVAprocedureandmathematicprincipleofconstituentdecodingalgorithmsuch嬲MAPAlgorith

7、m，EnhancedMax—LogMAPAlgorithmandthelikehasbeendescribedanddeducedindetailPerformanceandcomplexityhasbeendiscussedandcompared，SOastochoosethemostappropriatealgorithmtobeimplementedinconstituentdecodersModificationandimpro

8、vementtoCTCdecodingprocedurehavebeenresearchedRegardingthecircularityoftheCTCconstituentencoderstate，anewalgorithmRecursionFeedbackAlgorithmhasbeenintroduced，whichhelpstosolvetheproblemcomeacrossininitializingforwardandb