myselfchase_hard.m

是一个四发四收的球型译码程序

%==========================================
%16QAM;   1/2,3conv;    TX=4;RX=4;  硬判决
%==========================================
clc;
clear
Tx=4;
Rx=4;
M=16;
h=modem.qammod(M);
h2=modem.qamdemod(M);
Factor=10;
Table_bit=zeros(M,log2(M));
for i=2:M
    Table_bit(i,:)=de2bi(i-1,log2(M));
end
Ch_Q=[1.65 2.3 3.25 5 7.6 11.55 18];
%Ch_Q=1.65;

%L=input('please enter the length of the frame:');
SNRdB=input('please enter SNR:');
lenl=input('please enter the length of bit:');
%len=96*10;
L=1;
%SNRdB=5;

for SNRindex=1:length(SNRdB)
    SNRtemp=10.^((SNRdB+3)/10);
    SNR=SNRtemp(SNRindex);
sigma_n2=sqrt(Tx)/sqrt(SNR);
len=lenl(SNRindex);
msg=randint(len,1);
trel=poly2trellis(3,[6,7]);
code=convenc(msg,trel);
y=randintrlv(code,4831);
Sig_code=buffer(y,Tx*L*log2(M));
Sym_code=zeros(Tx*L*log2(M),2*len/(Tx*L*log2(M)));



for BloInd=1:2*len/(Tx*L*log2(M))
    %tranmit signal
    TxMatrix_bit_src=Sig_code(:,BloInd);
    TxMatrix_bit_map=reshape(TxMatrix_bit_src,Tx*L,log2(M));
    TxMatrix_sym_temp=bi2de(TxMatrix_bit_map);
    TxMatrix_sym=modulate(h,TxMatrix_sym_temp)/sqrt(Factor);
    TxMatrix=reshape(TxMatrix_sym,Tx,L);

    %channel
    for i=1:Rx
        Ch=(randn(Tx,L)+sqrt(-1)*randn(Tx,L)).*sqrt(0.5);
        TxPassCh=Ch.*TxMatrix;
        TxSum_temp=sum(TxPassCh);
        for k=1:L
            Ch_Equ(Rx*(k-1)+i,Tx*(k-1)+1:Tx*k)=(Ch(:,k)).';
        end
         Tx_Sum(i,:)=TxSum_temp;
    end
    %receive signal
    RxSig=Tx_Sum+sigma_n2*(randn(Rx,L)+sqrt(-1)*randn(Rx,L))/sqrt(2);
    %RxSig=Tx_Sum;
    RxSig_MF=reshape(RxSig,Rx*L,1) ;
    Ch_Total=Ch_Equ;
    
    [BLR,DeSymb,IX]=LLRnLayer(RxSig_MF,Ch_Total,M,sigma_n2,1,1,1);
    
    ind=IX(1);
    ChanCoff=Ch_Total(:,ind);
    Chan=horzcat(Ch_Total(:,1:ind-1),Ch_Total(:,ind+1:Tx));
    DetSignal=demodulate(h2,sqrt(Factor)*[DeSymb(ind,1)]);
    Det_bit=de2bi(DetSignal,log2(M),2);
    Bit_Vec=reshape(Det_bit,log2(M),1);
    Table_pertur=zeros(M,log2(M));
    Phi=zeros(M,1);
    Temp_Ind=0;
    for i=1:M
        Table_pertur(i,:)=xor(Table_bit(i,:),Bit_Vec.');
        Phi(i)=Phi(i)+Table_pertur(i,1:log2(M))*abs(BLR(1,1:log2(M)).');
        if Phi(i)<=Ch_Q(SNRindex)
            Temp_Ind=Temp_Ind+1;
            IndSet(Temp_Ind)=i;          
        end
    end
    IndSet=IndSet(:,1:Temp_Ind);
    ML_Matrix=zeros(Temp_Ind,1);
    
    for i=1:Temp_Ind
        Search_bit=Table_bit(IndSet(i),:);
        DetBitMap=reshape(Search_bit,1,log2(M));
        OrgSymb=bi2de(DetBitMap);
        Sym1=modulate(h,OrgSymb)/sqrt(Factor);
        ReSig=RxSig_MF-ChanCoff.*Sym1;
       
        Det_sig_temp=MIMONCZF(ReSig,Chan,M,sigma_n2,Factor,0);
        DetTemp(:,i)=vertcat(Det_sig_temp(1:ind-1,1),OrgSymb(1,1),Det_sig_temp(ind:Tx-1,1));
        Tx_sym=modulate(h,DetTemp(:,i))/sqrt(Factor);
        ML_Matrix(i)=norm(RxSig_MF-Ch_Total*Tx_sym,'fro')^2;
    end
    [MinValue,Index]=min(ML_Matrix);
    Det_sym_temp=DetTemp(:,Index);
    Det_bit=de2bi(Det_sym_temp,log2(M),2);
    dd_bit=reshape(Det_bit,Tx*L*log2(M),1);
    Sym_code(:,BloInd)=dd_bit.';

end
ncode=reshape(Sym_code,2*len,1);
b1 =  randdeintrlv(ncode,4831);  
decoded = vitdec(b1,trel,3,'trunc','hard');    


ber(SNRindex)=length(find(decoded-msg))/len;    
end
semilogy(SNRdB,ber)