mapping_ber.m

利用星座图重排策略的HARQ方案

%signal constellation arrangement scheme
SNR=0:5:30;
 Nt=4;
 Nr=4;
 M=16;
SymTime=10;
packetNum=100;
const=[1+j,1+j*3,3+j,3+j*3,1-j,1-3*j,3-j,3-3*j,-1+j,-1+3*j,-3+j,-3+3*j,-1-j,-1-3*j,-3-j,-3-3*j];
bin1=[];bin2=[];bin3=[];bin4=[];
bit1=[];bit3=[];averber=[];averber1=[];averber2=[];
for SNRindex=1:length(SNR)
    K=SNR(SNRindex);
    BER=0; BER1=0;BER2=0;
      for packetindex=1:packetNum
    H=(randn(Nr,Nt)+j*randn(Nr,Nt))/sqrt(2);
     for t=1:SymTime 
         transtime=1;  transtime1=1;
     bin1=randint(Nt,4);
     str1=num2str(bin1);
     data=bin2dec(str1);
     a=genqammod(data,const);
     r=awgn(H*a,SNR(SNRindex),'measured');
     out=blastdetect_16qam(H,Nt,r,M);
     [number ratio]=biterr(data,out);
     ratio1=ratio;
     x=real(genqammod(out,const));

   for m=1:Nt
     LLR1(m)=logm((exp(-K*(x(m)+1).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)-3).^2)));
     LLR2(m)=logm((exp(-K*(x(m)-3).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)+1).^2)));
   end
     LLR_1=LLR1;
     LLR_2=LLR2;
     for condition=1:3
         switch condition
             case 1
      if ratio~=0                     %the second transmission
        bin2(:,1:2)=bin1(:,3:4);
        bin2(:,3:4)=~bin1(:,1:2);
        str2=num2str(bin2);
        data2=bin2dec(str2);
        a=genqammod(data2,const);
        r=awgn(H*a,SNR(SNRindex),'measured');
        record_r=r;
        out=blastdetect_16qam(H,Nt,r,M);
        rec1=dec2bin(out);
        if size(rec1,2)==4
        rec=[~str2num(rec1(:,3)),~str2num(rec1(:,4)),str2num(rec1(:,1)),str2num(rec1(:,2))];
        elseif size(rec1,2)==3
           rec=[~str2num(rec1(:,2)),~str2num(rec1(:,3)),zeros(Nt,1),str2num(rec1(:,1))];
        elseif size(rec1,2)==2
          rec=[~str2num(rec1(:,1)),~str2num(rec1(:,2)),zeros(Nt,1),zeros(Nt,1)];
        else
            rec=[~zeros(Nt,1),~str2num(rec1(:,1)),zeros(Nt,1),zeros(Nt,1)];
        end
         out=bin2dec(num2str(rec));
       x=real(genqammod(out,const));
   for m=1:Nt
     LLR1(m)=logm((exp(-K*(x(m)+1).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)-3).^2)))+LLR1(m);
     LLR2(m)=logm((exp(-K*(x(m)-3).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)+1).^2)))+LLR2(m);
   end

        for m=1:Nt
        if LLR1(m)>0
            bit1(m,1)=1;
        else
            bit1(m,1)=0;
        end
       if LLR2(m)>0
            bit3(m,1)=1;
        else
            bit3(m,1)=0;
       end
        end
        combined_rec=[bit1,rec(:,2),bit3,rec(:,4)];
        [number ratio]=biterr(data,bin2dec(num2str(combined_rec)));
        if ratio~=0                   %the third transmission
            bin3(:,1:2)=bin1(:,3:4);
            bin3(:,3:4)=bin1(:,1:2);
            str3=num2str(bin3);
        data3=bin2dec(str3);
        a=genqammod(data3,const);
        r=awgn(H*a,SNR(SNRindex),'measured');
        out=blastdetect_16qam(H,Nt,r,M);
        rec1=dec2bin(out);
        if size(rec1,2)==4
        rec=[str2num(rec1(:,3)),str2num(rec1(:,4)),str2num(rec1(:,1)),str2num(rec1(:,2))];
        elseif size(rec1,2)==3
        rec=[str2num(rec1(:,2)),str2num(rec1(:,3)),zeros(Nt,1),str2num(rec1(:,1))];  
        elseif size(rec1,2)==2
        rec=[str2num(rec1(:,1)),str2num(rec1(:,2)),zeros(Nt,1),zeros(Nt,1)];
        else
        rec=[zeros(Nt,1),str2num(rec1(:,1)),zeros(Nt,1),zeros(Nt,1)];
        end
           out=bin2dec(num2str(rec));
           x=real(genqammod(out,const));
   for m=1:Nt
     LLR1(m)=logm((exp(-K*(x(m)+1).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)-3).^2)))+LLR1(m);
     LLR2(m)=logm((exp(-K*(x(m)-3).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)+1).^2)))+LLR2(m);
   end

        for m=1:Nt
        if LLR1(m)>0
            bit1(m,1)=1;
        else
            bit1(m,1)=0;
        end
         if LLR2(m)>0
            bit3(m,1)=1;
        else
            bit3(m,1)=0;
         end
        end
        combined_rec=[bit1,rec(:,2),bit3,rec(:,4)];
        [number ratio]=biterr(data,bin2dec(num2str(combined_rec)));
        if ratio~=0                  %the fourth transmission
         bin4(:,1:2)=bin1(:,1:2);
         bin4(:,3:4)=~bin1(:,3:4);
         str4=num2str(bin4);
        data4=bin2dec(str4);
        a=genqammod(data4,const);
        r=awgn(H*a,SNR(SNRindex),'measured');
        out=blastdetect_16qam(H,Nt,r,M);
        rec1=dec2bin(out);
        if size(rec1,2)==4
        rec=[str2num(rec1(:,1)),str2num(rec1(:,2)),~str2num(rec1(:,3)),~str2num(rec1(:,4))];
        elseif size(rec1,2)==3
        rec=[zeros(Nt,1),str2num(rec1(:,1)),~str2num(rec1(:,2)),~str2num(rec1(:,3))];    
        elseif size(rec1,2)==2
        rec=[zeros(Nt,1),zeros(Nt,1),~str2num(rec1(:,1)),~str2num(rec1(:,2))];
        else
        rec=[zeros(Nt,1),zeros(Nt,1),~zeros(Nt,1),~str2num(rec1(:,1))];
        end
           out=bin2dec(num2str(rec));
           x=real(genqammod(out,const));

   for m=1:Nt
     LLR1(m)=logm((exp(-K*(x(m)+1).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)-3).^2)))+LLR1(m);
     LLR2(m)=logm((exp(-K*(x(m)-3).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)+1).^2)))+LLR2(m);
   end
        for m=1:Nt
        if LLR1(m)>0
            bit1(m,1)=1;
        else
            bit1(m,1)=0;
        end
         if LLR2(m)>0
            bit3(m,1)=1;
        else
            bit3(m,1)=0;
         end
        end
        combined_rec=[bit1,rec(:,2),bit3,rec(:,4)];
        [number ratio]=biterr(data,bin2dec(num2str(combined_rec))); 
        end
        end
      end
      BER=BER+ratio;
             case 2
                 r1=[];
                 r1(:,1)=record_r;
                 ratio=ratio1;
                 x=genqammod(data,const);
                 while (ratio~=0&transtime<=4)
                     transtime=transtime+1;
              r1(:,transtime)=awgn(H*x,SNR(SNRindex),'measured');  
              r=sum(r1.').'/transtime;
              out=blastdetect_16qam(H,Nt,r,M);
              rec1=dec2bin(out);
              if size(rec1,2)==4
        rec=[str2num(rec1(:,1)),str2num(rec1(:,2)),str2num(rec1(:,3)),str2num(rec1(:,4))];
        elseif size(rec1,2)==3
        rec=[zeros(Nt,1),str2num(rec1(:,1)),str2num(rec1(:,2)),str2num(rec1(:,3))];    
        elseif size(rec1,2)==2
        rec=[zeros(Nt,1),zeros(Nt,1),str2num(rec1(:,1)),str2num(rec1(:,2))];
        else
        rec=[zeros(Nt,1),zeros(Nt,1),zeros(Nt,1),str2num(rec1(:,1))];
              end
         out=bin2dec(num2str(rec));
          x=real(genqammod(out,const));     
    for m=1:Nt
     LLR1(m)=logm((exp(-K*(x(m)+1).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)-3).^2)))+LLR_1(m);
     LLR2(m)=logm((exp(-K*(x(m)-3).^2)+exp(-K*(x(m)+3).^2))/(exp(-K*(x(m)-1).^2)+exp(-K*(x(m)+1).^2)))+LLR_2(m);
   end

               for m=1:Nt
                if LLR1(m)>0
                bit1(m,1)=1;
                else
                 bit1(m,1)=0;
                end
                 if LLR2(m)>0
                   bit3(m,1)=1;
                 else
                 bit3(m,1)=0;
                 end
                 end
        combined_rec=[bit1,rec(:,2),bit3,rec(:,4)];
        [number ratio]=biterr(data,bin2dec(num2str(combined_rec))); 
                 end
                 BER1=BER1+ratio;
             case 3
                r2=[];r=[];
                 r2(:,1)=record_r;
                 ratio=ratio1;
                 x=genqammod(data,const);
                 while (ratio~=0&transtime1<=4)
                     transtime1=transtime1+1;
              r2(:,transtime)=awgn(H*x,SNR(SNRindex),'measured');  
              r=sum(r2.').'/transtime1;
              out=blastdetect_16qam(H,Nt,r,M); 
              [number ratio]=biterr(data,out);
                 end
                 BER2=BER2+ratio;
         end
     end
     end
      end
      averber(SNRindex)=BER/SymTime/packetNum
      averber1(SNRindex)=BER1/SymTime/packetNum
      averber2(SNRindex)=BER2/SymTime/packetNum
end
semilogy(SNR,averber,'-r',SNR,averber1,'-b',SNR,averber2,'-g')
grid on
axis([0 30 10^-4 10^0])
legend('mapping diversity','bit chase combined','symbol chase combined')