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From: Robert Orzechowski on 31 Jan 2010 16:15
Hi, I have a SOVA decoder, which needs CSI to works fine.
I am using rayleighchan built-in function :

tau=0:5e-8:5e-7;
%path gain dB
pdb=[0.6286 0.4895 0.3813 0.2969 0.2312 0.1201 0.1403 0.1092 0.085 0.0662 0.0515];
chan = rayleighchan(4e-6, 200, tau, pdb);
chan.ResetBeforeFiltering = false;
chan.StoreHistory = true; %since matlab 2006a

y = filter(chan,trans);
h=chan.PathGains;

In this case I have 11 taps. So matrix h (in time domain) has a size FFT x 11.
How to get CSI ? doing simple fft(h) is not a good idea, since i got also 11 samples for the symbol given.
How to get channel state information if I have 11 path's gains

Please help me.
Robert
From: Idin Motedayen-Aval on 3 Feb 2010 15:41
Robert Orzechowski wrote:
> Hi, I have a SOVA decoder, which needs CSI to works fine.
> I am using rayleighchan built-in function :
>
> tau=0:5e-8:5e-7;
> %path gain dB pdb=[0.6286 0.4895 0.3813 0.2969 0.2312 0.1201 0.1403
> 0.1092 0.085 0.0662 0.0515];
> chan = rayleighchan(4e-6, 200, tau, pdb);
> chan.ResetBeforeFiltering = false;
> chan.StoreHistory = true; %since matlab 2006a
>
> y = filter(chan,trans);
> h=chan.PathGains;
>
> In this case I have 11 taps. So matrix h (in time domain) has a size FFT
> x 11.
> How to get CSI ? doing simple fft(h) is not a good idea, since i got
> also 11 samples for the symbol given.
> How to get channel state information if I have 11 path's gains
> Please help me.
> Robert

Hi Robert,
You already have your CSI. If you have the gain of each path, that's
your channel's state. Now it's up to you to figure out how you want to
use that information. If you're stuck on this point, do some reading on
equalization.
One idea might be to use a static filter first. Forget the fading
channel for now; just use a randomly generated 11-tap filter, and see if
you can deal with the signal after that filter (can you undo the effect
of the filter). Then you can worry about the time-varying nature of the
channel.

HTH,
Idin

--
Idin Motedayen-Aval
The MathWorks, Inc.
zq=[4 2 5 -15 -1 -3 24 -57 45 -12 19 -12 15 -8 3 -7 8 -69 53 12 -2];
char(filter(1,[1,-1],[105 zq])), clear zq
From: mahmud_dbm on 17 Feb 2010 14:38
Dear Sir,

I'm stuck with a problem in Rayleigh channel function, rayleighchan(ts,fd,tau,pdb),
now what is the actual "ts" i.e InputSamplePeriod for OFDM transmission,

Say my Operating frequency is 2.4GHz, and channel BW is 20MHz, and FFT size or Number of Bits per Symbol say it is 64, .. or how they'd be related to "InputSamplePeriod".... i need actual and exact value of "ts" for OFDM.

Help me out..
From: Robert Orzechowski on 17 Feb 2010 15:43
"mahmud_dbm " <mahmud_dbm(a)yahoo.com> wrote in message <hlhgjf$7e1$1(a)fred.mathworks.com>...
> Dear Sir,
>
> I'm stuck with a problem in Rayleigh channel function, rayleighchan(ts,fd,tau,pdb),
> now what is the actual "ts" i.e InputSamplePeriod for OFDM transmission,
>
> Say my Operating frequency is 2.4GHz, and channel BW is 20MHz, and FFT size or Number of Bits per Symbol say it is 64, .. or how they'd be related to "InputSamplePeriod".... i need actual and exact value of "ts" for OFDM.
>
> Help me out..


Seems like this is 802.11 channel, right ?
chan = rayleighchan(4e-6, 200, tau, pdb);

Please let me know if you find the solution how to get CSI from filter function....
From: Robert Orzechowski on 17 Feb 2010 15:47
"mahmud_dbm " <mahmud_dbm(a)yahoo.com> wrote in message <hlhgjf$7e1$1(a)fred.mathworks.com>...
> Dear Sir,
>
> I'm stuck with a problem in Rayleigh channel function, rayleighchan(ts,fd,tau,pdb),
> now what is the actual "ts" i.e InputSamplePeriod for OFDM transmission,
>
> Say my Operating frequency is 2.4GHz, and channel BW is 20MHz, and FFT size or Number of Bits per Symbol say it is 64, .. or how they'd be related to "InputSamplePeriod".... i need actual and exact value of "ts" for OFDM.
>
> Help me out..

Seems like you have 802.11 channel right ?
chan = rayleighchan(4e-6, 200, tau, pdb);

Let me know if you find how to get CSI from filter function...

regards,
Robert
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