Re: [Discuss-gnuradio] SNR estimation in ofdm using preamble symbol

[Martin Braun (CEL)]

On Sat, Apr 06, 2013 at 10:58:31AM -0500, Nathan West wrote:
> On Saturday, April 6, 2013, Pradeep Borado wrote:
> 
> 
>     HI , i am doing a project on channel estimation in ofdm . I want to
>     estimate the SNR of the recievd symbol using the preamble symbol.
> 
>     Please let me if i can do this in GNU radio. 
> 
> 
>  http://gnuradio.org/doc/doxygen/group__snr__blk.html Tom created and blogged
> about two blocks to do SNR. I've had success using both for PSK signals. One 
> is
> a probe that generates messages. The other is a pass through that generates
> tags.

This will indeed work if you serialize the frames into complex symbols,
but only if you have a flat fading channel!

You could also use the preamble, but will have to write your own block
for that since the preamble is discarded on reception in the current GNU
Radio blocks.

Estimating SNR for OFDM is marginally different than for single-carrier.
I suggest having a look at academic papers on this subject.

MB

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