一類QC-LDPC碼的構造.pdf

1、：、蠢i’llIlllitIIItIIIIIIII!1分類粵一Y3274814UDC學號密級一類QC—LDPC碼的構造許家齊M14319指導教師姓名：廑垂生：整撞：塹劌盤堂：婆菱揚劌：22三QQ窆申請學位級別：亟學科專業(yè)名稱：廛周數堂論文提交日期：2Q12生壘旦論文答辯日期：2Q12生月學位授予單位：揚劌盤堂學位授予日期：2Q!Z生魚旦答辯委員會主席：睦皇查熬撞2017年6月季Ⅲ文太一論葉叭仁“弘川刪位必埸一學㈤、)上◇駙II揚州大學碩

2、士學位論文AbstractSincethelow—densityparitycheck(LDPC)codeprovidesnear—capacityperformanceonmanychannelssuchasbinaryerasurechannel(BEC)，binarysymmetricchannel(BSC)，andadditivewhiteGaussiannoisechannel(AWGN)，ithasbeenmoreandmo

3、rewidelyusedinthefieldsofopticalcommunication，mobilecommunication，satellitecommunicationandinformationstorageAnimportantparameteraffectingtheperformanceanddeterminingefficiencyofiterativedecodingalgorithmsforLDPCcodes，is

4、thegirthwhichdeterminesthenumberofindependenceiterationsToacertainextent，thelongerthegirth，thebettertheperformanceThoughcomputersearch，FossorierconstructedBC—LDPCcodeswithgirth8，10，12respectivelyMEsmaeiliandMGholamiintro

5、ducedamethodconstructingQC—LDPCcodeswithmaximumgirth18applyingtheconceptofBSGandslopematricesLatertheypresentedtheconceptof(vb，3，1)一packingdesignandgaveaclassofQC—LDPCcodeswithgirth20Inthispaperweproposesomenew(vb，3，1)一p

6、ackingdesignswhoseincidencematricescanbeconsideredasmothermatricesofcolumnweightthreequasicycliclowdensityparitycheckcodesThemothermatrixhasthefollowingtwofeaturesFirst，eachcolumnhasonlythreenonzeroelementsSecond，inanyof

7、thetWOcolumns，thereisonlyonelocationinwhichthereisanonzeroelementInthemothermatrix，wereplacethenonzeroelementineachcolumnfromtoptobottomintheorderofplacementbyI，Isi，IsJSothat，wecangettheparity—checkmatrixofecLDPCcede，whi

8、chalsocanbecalledexpansionmatrixItcanbeprovedthatthemaximumlengthoftheQC—LDPCcodesconstructedbythismethodcanreach20TheshiftchainSisthevectorofallshiftindicesItisclearthatffweconfirmtheshiftchainS，wecangettheparitycheckma

9、trixofec—LDPCcodesOnthebasisofMEsmaeili’Ssearchalgorithm，weimprovethealgorithmofsearchingshiftchainS，fromtheoriginalcanonlydetermineasingleshiftindexvaluetodeterminethevalueofeachofthetwoshlflindmesAlthoughMEsmaefligavea

10、searchalgol‘ithmfortheshiftchainS，buttheydidn’tpointouthowtoconfirmtheconditionsoftheshiftchainSTherefore，thispapergivesarecursivesearchalgorithmtofindallshortcycleswhichlengthsarelessthan29inthemothermatrix，combinedwith