%BP迭代譯碼算法
function?Outputdecode=LDPCDecode（SignrowcolblockHsigmaIterNum）

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%clear
%clc
%row=16;col=32;block=4;SNR=1;k=1;
%H=GenH（rowcolblock）;
%InputM=randint（116*4）;
%PerEncode=LDPCEncode（InputMrowcolblockH）;
%[SignOutputCodeErrCodesigma]=BPSKAn（PerEncodeSNR）
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%???PerData用于誤比特判斷
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

rows=row*block;
cols=col*block;
LLRsigma=sigma;
IterNumLen=length（IterNum）;

%%%%%%%%%%%%%%%%%%%%%%%%%%
ErrDecode=zeros（1IterNumLen）;
%Outputdecode=zeros（IterNumLencols）;
%Outputdecode=zeros（2cols）;

%信道初始LLR值
LLRInitial=zeros（1cols）;
for?i=1:cols
????LLRInitial（1i）=2*Sign（1i）/（LLRsigma^2）;
end
LLRQ=zeros（rowscols）;??%變量點到校驗點的LLR信息
LLRR=zeros（rowscols）;??%校驗點到變量點的LLR信息

%初始化LLRQ
for?i=1:rows
????for?j=1:cols
????????if?H（ij）~=0
????????????LLRQ（ij）=LLRInitial（1j）;?
????????end
????end
end


%迭代過程
%maxiter=IterNum（IterNumLen）;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%OutputdecodeNum=zeros（maxitercols）;
Outputdecode=zeros（1cols）;
%m=1;
for?iter=1:IterNum
???
????%校驗點到變量點的LLR計算
????for?i=1:rows
????????for?j=1:cols
????????????if?H（ij）~=0%判斷H矩陣不為0的點進行迭代計算
????????????????
????????????????LLRRPro=1;%計算LLRR中Beita的積
????????????????
????????????????%計算變量節點傳向校驗節點的消息
????????????????for?k=1:cols
????????????????????if?H（ik）~=0&&k~=j%利用H矩陣對LLRQ值進行判斷
????????????????????????LLRRPro=LLRRPro*tanh（LLRQ（ik）/2）;
????????????????????end
????????????????end
????????????????
????????????????%信息為0時的處理
????????????????if?LLRRPro~=0
????????????????????LLRR（ij）=2*atanh（LLRRPro）;
????????????????????%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
????????????????????%if?LLRR（ij）==inf||LLRR（ij）==-inf
????????????????????%????LLRR（ij）=0;
????????????????????%end
????????????????else
????????????????????LLRR（ij）=0;
????????????????end
????????????end
????????end
????end
????%%%%%%%%%%%%%%%%%%%%%%%%%%%%
????%LLRR
????%變量點到校驗點的LLR計算
????for?i=1:cols
????????for?j=1:rows
????????????LLRMid=0;
????????????if?H（ji）~=0
????????????????for?k=1:rows
????????????????????if?k~=j&&H（ki）~=0
????????????????????????LLRMid=LLRR（ki）+LLRMid;%外信息加上除去本身的信道信息
????????????????????end
????????????????end
????????????????LLRQ（ji）=LLRMid+LLRInitial（1i）;%出過錯
????????????end
????????end
????end
????%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
????%LLRQ
????
????%迭代后碼字判斷
????LQ=zeros（1cols）;
???
????%計算后驗概率
????for?i=1:cols?
????????LQMid=0;
????????for?j=1:rows
????????????LQMid=LLRR（ji）+LQMid;
????????end
????????LQ（1i）=LQMid+LLRInitial（1i）;
????end
????
????%估計碼字
????decode=zeros（1cols）;
????%%%%%%%%%%%%%%%%%%
????%LQ
????for?i=1:cols
????????if?LQ（1i）<0
????????????decode（1i）=1;
????????end
????end
????%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
????%decode
????%SUM=sum（abs（PerData-decode（1:（length（PerData）））））
????%迭代次數判斷以及譯碼碼字和誤比特輸出
????%if?IterNum（1m）==iter
??????%??ErrDecode（1m）=sum（abs

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件????????4103??2011-09-15?12:56??QC-LDPC-迭代次數\LDPCDecode.m
?????文件????????5052??2020-02-29?15:54??QC-LDPC-迭代次數\main.m
?????文件????????2229??2012-06-23?10:32??QC-LDPC-迭代次數\QCEncode.m
?????文件????????2273??2020-02-27?16:05??QC-LDPC-迭代次數\QCLDPCbaseH.m