generatefade_jakes.m

cdma detectors like decoorelator mmse mf and others

function Fade=GenerateFade_Jakes(r,c,FadeRate)

fdTs=FadeRate;      % fade rate  
f=0:0.001:1;        % frequency point 1 corresponds to Nyquist rate "half the sampling rate" 

for jj=1:length(f)
    xx=(f(jj)/fdTs)^2;
    if xx<1 
        Sf(jj)=1./(2*pi*fdTs*sqrt(1-xx));
    end
    if xx==1 
        Sf(jj)=Sf(jj-1);
    end
    if xx>1 
        Sf(jj)=0.0; 
    end
end

N=10; % filter length 
b=fir2(N,f,sqrt(real(Sf)));

K=b*b';
b=b/sqrt(K);                    % Normalize power to one 

fi1=randn(length(b)-1,1);       % initial state of FIR filter 
x1=randn(r,c);                  % input WGN
[y1,fz1]=filter(b,1,x1,fi1);    % Correlated output noise 

fi2=randn(length(b)-1,1);       % repeat for qudrature component
x2=randn(r,c);
[y2,fz2]=filter(b,1,x2,fi2);

Fade=sqrt(0.5).*sqrt(y1.^2+y2.^2);