mingyangchen.m

MIMO-有关差分编码,用matlab书写,

function MYC
    Nt=4;%发射天线数为4
    Nr=1;%接收天线数为1
    max_snr=25;%最大的信噪设定为15
    symbol_per_frame=120;%每一帧的符号数为120个
    tot_frame_tx=zeros(1,max_snr+1);
    tot_err_symbol =zeros(1,max_snr+1);
    tot_err_bit=zeros(1,max_snr+1);
   for snr=0:max_snr
        for ii=1:10000
             tot_frame_tx(snr+1) = tot_frame_tx(snr+1)+1;
             bit_sequence = rand(1,symbol_per_frame * 2)>0.5;        %生成伪随机二进制待发送序列
             qpsk_sequence = QpskMapping(bit_sequence); %二进制信道与QPSK信号的转换
            sig =sqrt(4/(10^(snr/10)));  %归一化的噪声能量       
            addtional_gaussian_noise =sig * (randn(Nr,Nt,symbol_per_frame)/sqrt(2) + j*randn(Nr,Nt,symbol_per_frame)/sqrt(2)); %生成加性高斯噪声
            H=RayleighCH(Nr,Nt); %生成具有瑞利分布特性的信道衰落系数
            for k=1:4:symbol_per_frame-3
                X=[qpsk_sequence(k) j*(qpsk_sequence(k+1)) -conj(qpsk_sequence(k+2)) -conj(qpsk_sequence(k+3)); 
                   qpsk_sequence(k+1) qpsk_sequence(k) j*conj(qpsk_sequence(k+3))  -conj(qpsk_sequence(k+2));
                   qpsk_sequence(k+2) j*(qpsk_sequence(k+3)) conj(qpsk_sequence(k))  conj(qpsk_sequence(k+1));
                   qpsk_sequence(k+3) qpsk_sequence(k+2)  -j*conj(qpsk_sequence(k+1)) conj(qpsk_sequence(k)) ;];
                R=H*X+addtional_gaussian_noise(:,:,k);         %接收信号
                r1=R(1,1)*conj(H(1,1))+R(1,2)*conj(H(1,2))+conj(R(1,3))*H(1,3)+conj(R(1,4))*H(1,4);   
                r2=R(1,1)*conj(H(1,2))-j*R(1,2)*conj(H(1,1))-j*conj(R(1,3))*H(1,4)+conj(R(1,4))*H(1,3);
                r3=R(1,1)*conj(H(1,3))+R(1,2)*conj(H(1,4))-conj(R(1,3))*H(1,1)-conj(R(1,4))*H(1,2);   
                r4=R(1,1)*conj(H(1,4))-j*R(1,2)*conj(H(1,3))+j*conj(R(1,3))*H(1,2)-conj(R(1,4))*H(1,1);
                h1=conj(H(1,1))*H(1,2)+j*H(1,1)*conj(H(1,2))+j*H(1,3)*conj(H(1,4))+conj(H(1,3))*H(1,4);
                h2=H(1,3)*conj(H(1,4))-j*conj(H(1,3))*H(1,4)-j*conj(H(1,1))*H(1,2)+H(1,1)*conj(H(1,2));
                d=abs(H(1,1))^2+abs(H(1,2))^2+abs(H(1,3))^2+abs(H(1,4))^2;
               dh = [1+j 1+j;1+j -1+j;1+j -1-j;1+j 1-j;
                     -1+j 1+j;-1+j -1+j;-1+j -1-j;-1+j 1-j;
                      -1-j 1+j;-1-j -1+j;-1-j -1-j;-1-j 1-j;
                      1-j 1+j;1-j -1+j;1-j -1-j;1-j 1-j;]/sqrt(2);
                  for L=1:16
                D1(L)=d*(abs(dh(L,1))^2+abs(dh(L,2))^2)+2*real(conj(-r1)*dh(L,1))+2*real(conj(-r2)*dh(L,2))+real(conj(h1)*dh(L,1)*conj(dh(L,2))+conj(h2)*conj(dh(L,1))*dh(L,2));
                  end
                     [minnumber1 position1]=min(D1);%求出最小的距离
                X1=dh(position1,1);  %估计出x1的值
                X2=dh(position1,2);  %估计出x2的值
           
                    for L=1:16
                D2(L)=d*(abs(dh(L,1))^2+abs(dh(L,2))^2)+2*real(conj(-r3)*dh(L,1))+2*real(conj(-r4)*dh(L,2))+real(conj(h1)*dh(L,1)*conj(dh(L,2))+conj(h2)*conj(dh(L,1))*dh(L,2));
                  end
                [minnumber1 position2]=min(D2);%求出最小的距离
                X3=dh(position2,1);  %估计出x1的值
                X4=dh(position2,2);  %估计出x2的值
           
            
                if(X(1,1)~=X1)  
                     tot_err_symbol(snr+1)=tot_err_symbol(snr+1)+1;
                   if((X(1,1)+X1)==0)
                    tot_err_bit(snr+1)=tot_err_bit(snr+1)+2;
                   else
                          tot_err_bit(snr+1)=tot_err_bit(snr+1)+1; 
                     end
                  end
                  
                 if(X(2,1)~=X2)  
                     tot_err_symbol(snr+1)=tot_err_symbol(snr+1)+1;
                   if((X(2,1)+X2)==0)
                    tot_err_bit(snr+1)=tot_err_bit(snr+1)+2;
                   else
                          tot_err_bit(snr+1)=tot_err_bit(snr+1)+1; 
                     end
                  end
                  
                    if(X(3,1)~=X3) 
                     tot_err_symbol(snr+1)=tot_err_symbol(snr+1)+1;
                   if((X(3,1)+X3)==0)
                    tot_err_bit(snr+1)=tot_err_bit(snr+1)+2;
                   else
                          tot_err_bit(snr+1)=tot_err_bit(snr+1)+1; 
                     end
                  end
                  
                  if(X(4,1)~=X4)
                      tot_err_symbol(snr+1)=tot_err_symbol(snr+1)+1;
                    if((X(4,1)+X4)==0)
                    tot_err_bit(snr+1)=tot_err_bit(snr+1)+2;
                     else
                      tot_err_bit(snr+1)=tot_err_bit(snr+1)+1; 
                    end   
                 end
             end
        end
    end      
    
    
    %在不同信噪比条件下，求系统SER和BER
    ser_snr=tot_err_symbol./(tot_frame_tx * symbol_per_frame) ;
    ber_snr=tot_err_bit./(tot_frame_tx * symbol_per_frame*2);
    figure(1);
   semilogy(0:max_snr,ser_snr,'-o');
    grid
    hold on
    semilogy(0:max_snr,ber_snr,'-*');
    xlabel('SNR');
    ylabel('Error Ratio');
    legend('SER-SNR','BER-SNR');
    title('Ideal CSI');
    hold off