%space-time code matrix:[x1 x2 x3 x4;-x2* x1* -x4* x3*;x1 x2 -x3- x4;-x2* x1* x4* -x3*];

clear
Nt=4;
Nr=1;
l=0;
co_time=4;
min_snr=0; %minimum SNR
max_snr=20;%maximum SNR
SNR_step=2;
symbol_per_frame=1200;
tot_frame_tx=zeros(1,(max_snr-min_snr)/SNR_step+1);
tot_err_bit=zeros(1,(max_snr-min_snr)/SNR_step+1);
M=2;
if M==2
    dh=[1;j;-j;-1]/2;
    jd=[];
    dc=[0 0;0 1;1 0;1 1];
else
    dh=[1;(1-j)/sqrt(2);(-1+j)/sqrt(2);-1;(1+j)/sqrt(2);-j;j;(-1-j)/sqrt(2)]/2;
    dc=[0 0 0;0 0 1;0 1 0;0 1 1;1 0 0;1 0 1;1 1 0;1 1 1];
end




for snr=min_snr:SNR_step:max_snr
    clc
    disp('Wait until SNR=');disp(max_snr);
    snr
    sig =sqrt(1/4*Nt/(10^(snr/10)));   
    index=(snr-min_snr)/SNR_step+1;
    for fcnt=1:10
        tot_frame_tx(index) = tot_frame_tx(index)+1;
        bit_sequence=round(rand(1,symbol_per_frame));
        X1=[1 0 0 0;0 1 0 0;0 0 1 0;0 0 0 1];
        softbit=[];
      
        mapping_sequence =Mpskmod(bit_sequence,dh,M);
        for k=1:4:symbol_per_frame/M
            
            if((conj(mapping_sequence(k))*mapping_sequence(k+3)-mapping_sequence(k+1)*conj(mapping_sequence(k+2))~=0)&((abs(mapping_sequence(k)))^2+(abs(mapping_sequence(k+1)))^2+(abs(mapping_sequence(k+2)))^2+(abs(mapping_sequence(k+3)))^2)==1)
             b=(conj(mapping_sequence(k+1))*mapping_sequence(k+2)-mapping_sequence(k)*conj(mapping_sequence(k+3)))/(conj(mapping_sequence(k))*mapping_sequence(k+3)-mapping_sequence(k+1)*conj(mapping_sequence(k+2)));
            jd=acos(real(b));
             end
        
            
         
           X2=[ mapping_sequence(k)           mapping_sequence(k+1)        mapping_sequence(k+2)         mapping_sequence(k+3);
                -conj(mapping_sequence(k+1))  conj(mapping_sequence(k))    -conj(mapping_sequence(k+3))  conj(mapping_sequence(k+2));
                mapping_sequence(k+3)*exp(j*jd)           -mapping_sequence(k+2)        -exp(j*jd)*mapping_sequence(k+1)        mapping_sequence(k);
                -conj(mapping_sequence(k+2))   -exp(-j*jd)*conj(mapping_sequence(k+3))    conj(mapping_sequence(k))   exp(-j*jd)*conj(mapping_sequence(k+1));];
            X=X2*X1;
            
            H=(randn(Nt,Nr)+j*randn(Nt,Nr))/sqrt(2); 
            addtional_gaussian_noise1=sig*(randn(co_time,Nr)+j*randn(co_time,Nr))/sqrt(2);
            addtional_gaussian_noise=sig*(randn(co_time,Nr)+j*randn(co_time,Nr))/sqrt(2); 
            R1=X1*H+addtional_gaussian_noise1;
            R=X*H+addtional_gaussian_noise;
            D1=0;
            D2=0;
            D3=0;
            D4=0;
            for ii=1:Nr
                D1=D1+real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*dh);
                D2=D2+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*dh);
                D3=D3+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*dh);
                D4=D4+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*dh);
            end
           
            jd=pi
           
            a1=max(real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*(1/2))+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*(-1/2))+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*(-j/2))+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*(j/2)))
            a2=max(real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*(1/2))+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*(-1/2))+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*(j/2))+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*(-j/2)))
            a3=max(real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*(j/2))+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*(-j/2))+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*(1/2))+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*(-1/2)))
            a4=max(real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*(j/2))+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*(-j/2))+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*(-1/2))+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*(1/2)))
            a5=max(real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*(-j/2))+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*(j/2))+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*(1/2))+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*(-1/2)))
            a6=max(real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*(-j/2))+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*(j/2))+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*(-1/2))+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*(1/2)))
            a7=max(real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*(-1/2))+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*(1/2))+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*(j/2))+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*(-j/2)))
            a8=max(real((R1(1,ii)*conj(R(1,ii))+conj(R1(2,ii))*R(2,ii)+R1(4,ii)*conj(R(4,ii))+conj(R1(3,ii))*R(3,ii))*(-1/2))+real((-R(1,ii)*conj(R1(1,ii))+conj(R(2,ii))*R1(2,ii)-exp(j*jd)*R1(3,ii)*conj(R(3,ii))+exp(j*jd)*conj(R1(4,ii))*R(4,ii))*(1/2))+real((R1(3,ii)*conj(R(3,ii)) +conj(R1(4,ii))*R(4,ii)-R1(2,ii)*conj(R(2,ii))-conj(R1(1,ii))*R(1,ii))*(-j/2))+real((R1(1,ii)*conj(R(1,ii)*exp(j*jd))-conj(R1(3,ii))*R(3,ii)+R1(4,ii)*conj(R(4,ii))-conj(R1(2,ii))*R(2,ii)*exp(j*jd))*(j/2)))
            
            A=[a1,a2,a3,a4,a5,a6,a7,a8];
            [y,I]=max(A)
            if  l==1 
                x1=1/2;x2=-1/2;x3=-j/2;x4=j/2;
            elseif l==2
                x1=1/2;x2=-1/2;x3=j/2;x4=j/2;
            elseif l==3
                x1=j/2;x2=-j/2;x3=1/2;x4=-1/2;
            elseif l==4
                x1=j/2;x2=-j/2;x3=-1/2;x4=1/2;
            elseif l==5
                x1=-j/2;x2=j/2;x3=1/2;x4=-1/2;
            elseif l==6
                x1=-j/2;x2=j/2;x3=-1/2;x4=1/2;
            elseif l==7
                x1=-1/2;x2=1/2;x3=j/2;x4=-j/2;
            else
                x1=-1/2;x2=1/2;x3=-j/2;x4=j/2;
            end    
            
            
            softbit=[softbit x1 x2 x3 x4];
            X1=X; 
           
        end
        
        for k=1:symbol_per_frame
            if bit_sequence(k)~=softbit(k);
                tot_err_bit(index)=tot_err_bit(index)+1;
            end  
        end
    end
end 

ber_snr=tot_err_bit./(tot_frame_tx*symbol_per_frame);
semilogy(min_snr:SNR_step:max_snr,ber_snr,'-*');
xlabel('SNR');
ylabel('BER');
title('Ideal CSI');
grid on;