DQPSk調制過程 解調過程 系統誤碼率 matlab程序



N_Trials=1000;
N_number=100;
N_snr=10;
Q=16;

BER_MATRIX=[];
SER_MATRIX=[];
for trials=1:N_Trials
    trials
noise=randn(1,N_number/2)+j.*randn(1,N_number/2); 
s10=round(rand(1,N_number));
s=(s10*2-1)/sqrt(2);
sreal=s(1:2:N_number);
simage=s(2:2:N_number);
sc=sreal+j.*simage;
sgma=1;
Error_ber=[];
Error_ser=[];
    for snr_db=0:1:N_snr
        snr=10.^(snr_db./10);

        N0=2*sgma.^2;
        Eb=snr*N0;
        Es=2*Eb;
        yy=sqrt(Es).*sc+noise;
        y_real=sign(real(yy))./sqrt(2);
        y_image=sign(imag(yy))./sqrt(2);
        
        d_bit=[];
        for k=1:length(y_real)
            d_bit=[d_bit,[y_real(k),y_image(k)]];
        end
        d_symbol=y_real+j.*y_image;
        
          dif_bit=s-d_bit;  
          dif_symbol=sc-d_symbol;
          
          ber_snr=0;
          for k=1:N_number
          if dif_bit(k)~=0
              ber_snr=ber_snr+1;
          end
      end
      Error_ber=[Error_ber,ber_snr];
      
      ser_snr=0;
      for k=1:N_number/2
          if dif_symbol(k)~=0
              ser_snr=ser_snr+1;
          end
      end
      Error_ser=[Error_ser,ser_snr];
      
        %s_e=sign(y_real);
        %s_e10=(s_e+1)./2;
        %Error_snr=sum(abs(s10-s_e10));
        %Error_v=[Error_v,Error_snr];
    end
   BER_MATRIX=[BER_MATRIX;Error_ber] ;
   SER_MATRIX=[SER_MATRIX;Error_ser];
end

   BER_sum=mean(BER_MATRIX);
   BER=BER_sum./N_number;
   SER_sum=mean(SER_MATRIX);
   SER=SER_sum./(N_number./2);
   
BER_T=[];
SER_T=[];
   for snr_db=0:1:N_snr
      snr=10.^(snr_db./10);
       BER_THEROY=Qfunct(sqrt(2.*snr));
       SER_THEROY=1-(1-0.5.*erfc(sqrt(snr))).^2;
       BER_T=[BER_T,BER_THEROY];
       SER_T=[SER_T,SER_THEROY];
   end
   i=0:1:10;
   semilogy(i,BER,'-r',i,BER_T ,'*g',i,SER,'.c',i,SER_T,':k');



 function[y]=Qfunct(x);
y=(1/2)*erfc(x/sqrt(2));