Hello,
At the Rx once the FFT operation is done u need
to multiply it by the FFT of the channel (freq. domain
equalization). So this is equalivalent to the MIMO
flat fading channel model, hence u can use
conventional MIMO detection techniques. So each H is
the fft of the channel, so u will have different
realizationas of H (depends on the size of the FFT)
for each symbol, hence erogoic.
HTH,
-SaiRamesh.
--- Tine Celcer wrote:
> Hi,
>
> Thank you for the response. I am aware of the things
> that you mentioned, my
> concern is, with the channel matrix I should use for
> the ST decoding, when I
> have to calculate the pseudo inverse (for Zero
> Forcing for example).
>
> My channel is composed of three matrices of size
> Ntr, which in combination
> with the appropriate delay represent channel
> response for each tap. Now, at
> the receiver side I need a single matrix
> representing channel response, for
> which I have to calculate a pseudo inverse. My
> problem is which matrix
> should I use. I'm thinking, maybe I could use only
> the first tap matrix,
> since the other two are considerably attenuated, and
> I wouldn't make such a
> big mistake.
>
> Tine
>
>
>
>
>
> -----Original Message-----
> From: nammi sairamesh [mailto:s...@yahoo.com]
>
> Sent: Monday, October 08, 2007 2:19 AM
> To: t...@ijs.si; m...
> Subject: Re: [matlab] Space-Time decoding in
> multipath MIMO-OFDM system
>
> Hello,
> for MIMO -OFDM, at the Tx and Rx we use
> IFFT
> and FFT repectively for each antenna branch. At the
> Rx
> after FFT, each we can write as flat fading
> component.
> Hence, even though the channel is multipath
> (Selective), after FFT it is flat fading MIMO model.
> Hence u can use the stD. MIMO detectors.
> HTH,
> -SaiRamesh.
> --- t...@ijs.si wrote:
>
> > Hello,
> >
> > I'm working on a MIMO-OFDM system simulation in
> > Matlab. I assume a 3 tap multipath channel. My
> > question concerns the Space-Time decoding block at
> > the receiver side.
> > When decoding a ST coded signal, ussually a pseudo
> > inverse of a channel matrix H has to be calculated
> > (zero forcing, MMSE, SIC, OSIC algorithms). In a
> > single tap channel this is a trivial problem.
> > However, my problem is that I have three matrices,
> > each presenting one tap, delayed in time. I don't
> > really know how to calculate the inverse directly.
> > Should I use only the matrix for the first tap,
> with
> > the highest mean power(and hence aproximate the
> > channel state information at the receiver), or is
> > there any better, more precise way (but more
> complex
> > of course)?
> >
> > Thanks, Tine
> >
>
____________________________________________________________________________
> ________
> Be a better Heartthrob. Get better relationship
> answers from someone who
> knows. Yahoo! Answers - Check it out.
>
http://answers.yahoo.com/dir/?link=list&sid96545433
____________________________________________________________________________________
Need a vacation? Get great deals
to amazing places on Yahoo! Travel.
http://travel.yahoo.com/