Rician Channel in OFDM Simulation

Hi here,

I'm now simulation OFDM Systems in WLAN with Matlab. As to the Rician
Fading Channel,
1. Since WLAN enrioment is a static frequency-flat channel, do you
think the following clauses is enough in Channel simulation?

chan = rayleighchan;
signal_out = filter(chan,signal_in);

2. I also see someone using such clauses to descripe the Rician
channel.

Kmax = ceil(10* ExpDecayTrms*SampFreq);
% what is Kmax for? the number of the path?
var0 = (1 - exp( - 1/(SampFreq*ExpDecayTrms))) / (1 - exp(
-1*((Kmax+1)*SampFreq/ExpDecayTrms)));
% why SampFreq/ExpDecayTrms ?

k = (0:Kmax);
env = var0 * exp( - k/(SampFreq*ExpDecayTrms));

stdDevReOrIm = sqrt(env/2);
cir = stdDevReOrIm .* (randn(1, Kmax+1) + j*randn(1, Kmax+1));

signal_out = conv(signal_in, cir);

Could you explain?

Hi,

I'm not sure about the first qn, but for the 2nd implementation, it's
based on Naftali Chayat's channel model and it actually describes an
xponentially decaying Rayleigh Fading channel. 

It has been mentioned here:
http://www-mtl.mit.edu/~perrott/Distribution/CppSim_windows/ofdm_tutorial.pdf

My knowledge is limited but hope the above helps.

..Nekiy

>2. I also see someone using such clauses to descripe the Rician
>channel.
>
>Kmax = ceil(10* ExpDecayTrms*SampFreq);
>% what is Kmax for? the number of the path?
>var0 = (1 - exp( - 1/(SampFreq*ExpDecayTrms))) / (1 - exp(
>-1*((Kmax+1)*SampFreq/ExpDecayTrms)));
>% why SampFreq/ExpDecayTrms ?
>
>k = (0:Kmax);
>env = var0 * exp( - k/(SampFreq*ExpDecayTrms));
>
>stdDevReOrIm = sqrt(env/2);
>cir = stdDevReOrIm .* (randn(1, Kmax+1) + j*randn(1, Kmax+1));
>
>signal_out = conv(signal_in, cir);
>
>Could you explain?
>
>




		
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Nice reference!

Naftali's work (and his minion's, ;)) did provide the basis for the
802.11a channel model (as well as a lot of other features in 802.11a).

It just seemed interesting to me that this popped up here...   ;)


On Tue, 31 May 2005 07:05:08 -0500, "nekiy" <y_i_k_e_n@yahoo.co.uk>
wrote:

>Hi,
>
>I'm not sure about the first qn, but for the 2nd implementation, it's
>based on Naftali Chayat's channel model and it actually describes an
>xponentially decaying Rayleigh Fading channel. 
>
>It has been mentioned here:
>http://www-mtl.mit.edu/~perrott/Distribution/CppSim_windows/ofdm_tutorial.pdf
>
>My knowledge is limited but hope the above helps.
>
>..Nekiy
>
>>2. I also see someone using such clauses to descripe the Rician
>>channel.
>>
>>Kmax = ceil(10* ExpDecayTrms*SampFreq);
>>% what is Kmax for? the number of the path?
>>var0 = (1 - exp( - 1/(SampFreq*ExpDecayTrms))) / (1 - exp(
>>-1*((Kmax+1)*SampFreq/ExpDecayTrms)));
>>% why SampFreq/ExpDecayTrms ?
>>
>>k = (0:Kmax);
>>env = var0 * exp( - k/(SampFreq*ExpDecayTrms));
>>
>>stdDevReOrIm = sqrt(env/2);
>>cir = stdDevReOrIm .* (randn(1, Kmax+1) + j*randn(1, Kmax+1));
>>
>>signal_out = conv(signal_in, cir);
>>
>>Could you explain?
>>
>>
>
>
>
>
>		
>This message was sent using the Comp.DSP web interface on
>www.DSPRelated.com

Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org

Many Thanks for Nekiy's help! It's very useful