prasad6.m

In this project we analyze and design the minimum mean-square error (MMSE) multiuser receiver for un

N=64;
K=32;
z=[6 7 8 9 10 11 12 13 14 15 16 17];
snr=power(10,z/10);
R=[1 2 3 4 5 6 7 8];
L=power(2,R);

delta=[1.5956,0.9957,.5860,0.3352,0.1881,0.1041,0.0569,0.0308];


for i=1:N
    for j=1:K
        r=randint;
        s(i,j)=(2*r-1)/sqrt(N);
    end
end




for i=1:8
    x(1)=-inf;
    x(L(i)+1)=inf;
    
    
    for k=2:L(i)
        x(k)=(k-(L(i)+2)/2)*delta(i);
    end
    for k=1:L(i)
         y(k)=(k-(L(i)+1)/2)*delta(i);
    end
    g=0;
    for k=1:L(i)
         g=g+y(k)*(exp(-x(k)^2/2)-exp(-x(k+1)^2/2));
    end
    alpha_g(i)=g/(sqrt(2*pi));
    e=0;
    for k=1:L(i)
        e=e+(y(k)^2)*(qfunc(x(k))-qfunc(x(k+1)));
    end
    var_eta(i)=e-alpha_g(i)^2;
end





    
    a=s(1:N,5);
    for h=1:8
    for j=1:12
     c=1+var_eta(h)*(1+K*snr(j)/N)/(alpha_g(h)^2);
        
        b=inv(snr(j)*s*eye(K,K)*s'+eye(N,N)*c);
        U(h,j)=snr(j)*a'*b*a;
        gamma(h,j)=U(h,j)/(1-U(h,j));
    ber(h,j)=qfunc(sqrt(gamma(h,j)));
    end
    end
%     hold on
    for h=1:5
      ber1(h,:)= log10(ber(h,1:12));
%        plot(z,ber1)
    end
plot(z,ber1(1,:),'--r');grid on;hold on;
plot(z,ber1(2,:),'--b');grid on;hold on;
plot(z,ber1(3,:),'--m');grid on;hold on;
plot(z,ber1(4,:),'--k');grid on;hold on;
plot(z,ber1(5,:),'--g');grid on;hold on;