af3.asv

AF上跳协作分集的实现

%29/8/2008 ZHANGSONG
%根据论文《AF三跳协作分集...》编写仿真程序
%===========================================
function BER=vz
Qsd=sqrt(10^(Dsd/10));
Qs1=sqrt(10^(Ds1/10));
Q12=sqrt(10^(D12/10));
Q2d=sqrt(10^(D2d/10)); 
N=10240;
max_snr=25;
BER=zeros(1,max_snr);
ber=zeros(1,max_snr);
for SNR=0:max_snr
    %噪声归一化
    N0=1/(10^(SNR/10)); %N0为方差
    x=rand(1,N)>0.5;
    X=QpskMapping(x);
    Xd=[];
    M=length(X);
    for i=1:M
        %产生高斯白噪声
        Nsd=sqrt(N0)*(randn+j*randn);
        Ns1=sqrt(N0)*(randn+j*randn);
        N12=sqrt(N0)*(randn+j*randn);
        N2d=sqrt(N0)*(randn+j*randn);
        %信道增益
        Hsd=Qsd*(randn+j*randn);
        Hs1=Qs1*(randn+j*randn);
        H12=Q12*(randn+j*randn);
        H2d=Q2d*(randn+j*randn);
        %优化功率分配算法
        %=============================
        A=(Q2d+Q12)^2*Q12*Qs1^2;
        B=Q2d^2*Q12^3;
        if A~=B
            Es=(A-4*B+sqrt(A^2+8*A*B))/(4*(A-B));
        else
            Es=2/3;
        end
        E1=Q2d/(Q2d+Q12)*(1-Es);
        E2=1-E1-Es;
        %===============================
        %协作节点的放大增益
        %===============================
        B1=sqrt(E1/(Es*Hs1^2+N0));
        B2=sqrt(E2/(E1*H12^2+N0));
        %===============================
        %最大合并比加权因子计算
        A0=sqrt(Es)*conj(Hsd)/N0;
        A1=sqrt(Es)*B1*B1*conj(Hs1)*conj(H12)*conj(H2d)/...
            (B1^2*B2^2*abs(H12)^2*abs(H2d)^2+B2^2*abs(H2d)^2+1)/N0;
        %接收信号
        Y1=sqrt(Es)*X(i)*Hs1+Ns1;
        Y2=B1*Y1*H12+N12;
       % Y=A0*(sqrt(Es)*X(i)*Hsd+Nsd)+A1*(B2*Y2*H2d+N2d);
        Y=A0*(sqrt(Es)*X(i)*Hsd+Nsd)+A1*(B2*Y2*H2d+N2d);
        %解调
        dh = [1+j -1+j -1-j 1-j]/sqrt(2);
        D1=abs(Y*[1 1 1 1]-dh).^2;
        [minScale1 positionmin1]=min(D1);
        Xd=[Xd dh(positionmin1)];
    end
    xd=QpskInverseMapping(Xd);
    err1=(x==xd);
    tot_err1=0;
     for i=1:N
        if err1(i)==0
           tot_err1=tot_err1+1;
        end
     end
     BER(SNR+1)=tot_err1/N;
%理论值
ber(SNR+1)=(3/8)*N0^2*(1/(Es^2*Qsd^2*Qs1^2)+1/(Es*E1*Qsd^2*Q12^2)+1/(Es*E2*Qsd^2*Q2d^2));
end
%semilogy(0:max_snr,BER,'r');
%hold on
semilogy(0:max_snr,ber);