function sy=softdec(receive)
len=length(receive);
sy=zeros(1,len/2);
n=len/8;
G=[1 0 0 3 0 3 3 2;0 1 0 1 0 1 0 1;0 0 1 1 0 0 1 1;0 0 0 0 1 1 1 1];
b=[0 0 0 2 0 0 2 0];
com=zeros(1,8);
r=zeros(256,8);
rs=zeros(256,1);
source=zeros(256,4);
yy=zeros(1,8);
y=zeros(1,8);
for j=1:4
    for k=1:4
        for l=1:4
            for m=1:4
                p=[j-1 k-1 l-1 m-1];
                com=p*G+b;
                comm=mod(com,4);
                for z=1:8
                    if comm(z)==0
                        y(z)=1+i;
                    elseif comm(z)==1
                        y(z)=-1+i;
                    elseif comm(z)==2
                        y(z)=-1-i;   
                    else  y(z)=1-i;
                    end
                end
                x=(j-1)*64+(k-1)*16+(l-1)*4+m;
                source(x,:)=p;
                r(x,:)=y;
            end
        end
    end
end
for q=1:n  
    yy=receive(q*8-7:q*8);
    yyy=fft(yy,8);
    rsr=real(r)*(real(yyy).');
    rsi=imag(r)*(imag(yyy).');
    rs=rsr+rsi;
    [m,w]=max(rs);
    sy(q*4-3:q*4)=source(w,:);
end