基于后向狀態(tài)轉(zhuǎn)移算法的Turbo碼重量譜計算算法研究.pdf

1、西南交通大學(xué)碩士學(xué)位論文基于后向狀態(tài)轉(zhuǎn)移算法的Turbo碼重量譜計算算法研究姓名：高素月申請學(xué)位級別：碩士專業(yè)：通信與信息系統(tǒng)指導(dǎo)教師：陳慶春20090501西南交通大學(xué)碩士學(xué)位論文第|l頁AbstractAsacapacityapproachingelTorcorrectioncodeTurbocodeshavereceivedgreatattentionduetoitsimpressiveperformanceThereiSanum

2、berofresearchworkintermsofeithertheoreticalanalysisorpracticalimplementationconsiderations也eexistingstraightforwardalgorithmforthedeterminationofweightspectrumofconvolutionalcodescannotbeextendeddirectlytoaccuratelycalcu

3、latethedistancespectrumofTurbocodesduetothepresenceofinterleaverAlthoughtherearesomealgorithmsproposedrecentlytheaccuratedistancespectrumcalculationalgorithmforTurbocodesiSnotsufficientAfterabriefsurveyofthechannelcoding

4、theorythestateoftheartofTurbocodesandtheweightspectrumdeterminationproblemforTurbocodesarepresentedatfirstItiSshownthat，weighttwoinputsearchalgorithm，erroreventssearchalgorithm，theconstrainedsubcodesearchalgorithmarethre

5、eprimaryknownschemesforthefreedistance／weightspectrumestimate／calculationSOfarAndtheconstrainedsubcodesearchalgorithmanditsvariationsaretheonlyknownonethatoffersaneffectivemethodtogettheaccurateweightdistributionknowledg

6、eforaspecificTurbocodesItiSunveiledthatthecriticalproblemiShowtoaccuratelyevaluatetheSOcalledConstrainedInputandtheMinimumOutputhammingWeight(CⅡⅥOW)ofthecomponentRSCencoderforanyinputcandidateThenanewalgorithmoftheSOcall

7、edBackwardStateTransitionbased(BSTlalgorithmisproposedtosolvetheCIMOWprobleminthefirstst印，anddetermine，thefreedistanceforTurbocodesbyincorporatingitselfintotheconstrainedsubcodealgorithmTheproposedBSTalgorithmdistinguish

8、itselfwiththeprevisoulyproposedalgorithminthefollowingtwoaspects：statetransitionmergingandbackwardcomputationItiSunveiledthatmultipleconsecutive“0”inputconstraintsornonconstraintscouldbemergedintoonest印，thustheBSTalgorit

9、hmcouldbeutilizedtoimprovethecomputationefficiencyMeanwhile，itiSshownthat，twotricks，ie，byincludinginputweightintotheCIMOWdeterminationforthesecondcomponentcodeandabackwardtraversesearching，Canimprovethee硒ciencyaswellItis

10、validatedbycomparisonthat，theproposedalgorithmcangetexactlythesamefleedistanceandmultiplicitiesasthosebyusingtheGarello’Sconstrainedsubcodealgorithmforthe3GPPstandardTurbocodesThentheBSTbasedconstrainedsubcodealgorithmiS