Modelling of Wireless channel

[er.rakeshjain]

modelling a wireless channel

Dear all,
I have simulated WiMAX Transmitter and receiver in Matlab. Now I want to introduce channel effect between tx and Rx. Pls guide me to model the channel in MATLAB.

 

[Joatt]

There are two effects that you should consider in your channel: noise and passband limitation (banwidth).

If you are working on Simulink, you can add a "White Gaussian Noise" generator to your circuit, and a bandpass filter for passband limitation (The passing bandwith of the filter is the working frequency rane of your antenna).

However, if you are using Matlab codes only, you can generate a random noise by a code similar to:

noise=0.7*randn(size(t));

and then add it to your transmitted signal. Then, apply the following filter on your transmitted signal:

nsignal = signal + noise; % transmitted signal after adding the noise
flo = 2e9;
fup = 3e9; % assuming here that freq. range of the antenna is 2~3 GHz
fc = (flo + fup)/2;
fs = 4.5e9; % stopband frequency
Wp = [flo fup]/(fs/2); % normalized passband interval 
Ws = [(fc/2) (fc+(fc/2))]/(fs/2); % normalized stopband interval 
Rp = 3; % 3-dB attenuation at passband 
Rs = 30; % 30-dB attenuation at stopband 
[n,Wn] = buttord(Wp,Ws,Rp,Rs); % Butterworth filter 
[b,a] = butter(n,Wn);
channelsignal = filter(b, a, nsignal); % The resulting signal

Regards

 

[er.rakeshjain]

Thanks for your reply. I will try it.

 

[laxmi]

dear all
i am doing thesis in k- best algorithm for mimo detection. for this i want matlab simulation environment, where transmit signals, which channel, what noise etc.

 

[er.rakeshjain]

How can I add Fading effect and Delay Spread in Channel using Matlab.
How will I estimate channel at the receiver using pilots. I used pilots in my transmitted signal but at the receiver side simply extracting them. How pilots will be used to estimate channel and apply correction to the signal.