Re: [Discuss-gnuradio] GMSK Over the Air

[Martin Braun]

On Mon, Feb 27, 2012 at 12:12:52PM -0800, justynnuff wrote:
> The Problem: Although I can see the GMSK signal on the Rx end off of the
> USRP, nothing is produced at the output of the packet decoder.  The BT param
> on the GMSK mod block is ~1, the samples per symbol is 8, and almost
> everything else is default.  Is there something I'm missing, or does this
> block just not work in an over-the-air scenario?

Hi justynnuff,

it should work (and I've tried it). I don't have a setup right here, so
I can't give you a working example, but here's some input:
- I definitely used different params (probably bt=.3 and sps=2),
  although I don't know off the top of my head if that could cause
  trouble.
- The standard sync was a bit flaky (e.g. I never got it working on GSM
  bursts). I had to tune pretty precisely to start with, and then timing
  sync using the M&M didn't work out that well.

It does, however, work with the benchmark_* examples, which you should
definitely read (if you haven't done so). It's probably just a matter of
setting the sync params correctly.

MB

-- 
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin Braun
Research Associate

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KIT -- University of the State of Baden-Württemberg and
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