Re: [Discuss-gnuradio] SNR estimation for QAM modulation

[West, Nathan]

On Fri, Jan 24, 2014 at 2:37 PM, Henry Jin <address@hidden> wrote:
> Hi all,
>
> I'm wondering if SNR estimation by using the probe_mpsk_snr_est_xx can be
> applied to QAM modulation as well? I checked the source code and found
> nothing specific tied to MPSK modulation. Also, I found Tom has a blog about
> SNR estimator years ago
> http://www.trondeau.com/grcon12-hackfest/2012/10/1/snr-estimators.html
> But it seems the referred grc file has been removed. Can I still get the
> files from some repository?
>
> Thanks
> Henry
>

Hi Henry,

I think the underlying assumptions to the algorithms are specific to
PSKs rather than the code. You might look at papers describing the
algorithms to get an idea of whether they are suitable for QAM or not.
If not, you might find another algorithm that you can implement. This
post has a little more detail (although it's earlier than the one you
link to) http://www.trondeau.com/blog/tag/snr . It might be a good
idea to read through the paper Tom cites in that article since it
appears to be a good overview.

A quick search turned up this paper
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4224661&tag=1 I
didn't read through the whole paper and I'm not really familiar with
M2M4 other than it calculates the 2nd and 4th moments, but the
conclusion suggests M2M4 is probably good for QAM.