function [Pb]=SSK(bit_to_antenna)
N=1e6;
[M,Nt]=size(bit_to_antenna);
Nr=1;
snr=-10:2.5:30;
Pb=zeros(length(snr),1);
for j=1:length(snr)
logi_v=rand(M,N);
S=zeros(M,N);
S_t=S;
S((0<=logi_v)&(logi_v<=0.5))=1;% 多进制随机序列的产生
for i=1:N
H=sqrt(0.5)*(randn(Nr,Nt)+1i*randn(Nr,Nt));
W=sqrt(1/(2*10^(snr(j)/10)))*(randn(Nr,1)+1i*randn(Nr,1));
tecent=[0;0];
X=zeros(Nt,1);
for i1=1:Nt
if norm(S(:,i)-bit_to_antenna(:,i1))<1e-5&&(norm(tecent)<norm(H(i1)));
tecent=H(i1);
l=i1;
end
end
X(l)=1;%根据比特流搜索要发射的天线
Y=H*X+W;
for k=1:Nt
X_t=zeros(Nt,1);
X_t(k)=1;
if k==1
e_ml=norm(Y-H*X_t);
I=1;
elseif e_ml>=norm(Y-H*X_t);
e_ml=norm(Y-H*X_t);
I=k;
end
end
S_t(:,i)=bit_to_antenna(:,I);
end
Pb(j)=sum(sum(xor(S,S_t)))/(M*N);
end
