multipath fading matlab code required

if any body have multipath fading matlab code
and there category specification (A,B,C) for wireless channel
please send it urgently or suggest any link

hi mukul,

I seems to remember that Mathworks has simulink model of the communication system with the multipath fading channel. (not 100% sure)

As far as I remember it was in one of the webinar presented by mathworks engineer. (for some of the webinars you can download the code so if you are lucky and if I am not mistaken you can download the simulink model of the fading channel from there)

You can check at the www.mathworks.com at their archived webinars

Best Regards
dora

Hi,
Just use the model and you have more control over it. All you are supposed to do is add two phase shifted signals. Amplitude does not change much.
B R M

It uses deterministic channel modeling. in normal cases we get different multipaths from different directions and their amplitude is also different. the final signal we get is the sum of all the signals. the doppler spread of the signal also depends on the direction of arrival. for simulating the multipath u just need to multiply with the channel coefficients. it gives normalized values with a channel gain of 1.
function [chancoef]=flatfadechan(M,v,nobits,fs)
%M is the no of exp u want to add it depends on the no of multipaths reaching u . more the value of M better the frequency spectrum but it takes a lot of time to simulate so generally use around 10 to 20.
%v is the velocity, fs is sampling frequency, nobits is the no of samples of channel coefficient u want to generate
a=randn(1,M);
fdop=v*100/54;
k=cos(2*pi*rand(1,M));
theta=2*pi*rand(1,M);
time=0:1/fsnobits-1)/fs;
y=zeros(1,length(time));
for i=1:M
y=y+exp(j*(2*pi*fdop*time*k(i)+theta(i)));
end
chancoef=abs(y/sqrt(M));
return