Re: [Discuss-gnuradio] How to speed up spectrum sensing?

[devin kelly]

Changing the fft size won't change your sensing time that much unless the machine you're using is really slow or the fft size is outrageous.  What fft sizes are you using?

What will affect your sensing time more is the sampling/decimation rate you sent, the tune delay, and the dwell delay.  Be careful when changing the tune delay, if it is too short your data will be corrupted.

Look at the usrp_spectrum_sense.py code and try this:

$ python usrp_spectrum_sense.py --help

Also, since you're only trying to look at a narrow band, usrp_spectrum_sense.py isn't for you. This script is really for looking at different bands and different times, but you really only need to look at one band.  Basically, you never need to retune and a lot of that script does is retune.

Devin

On Sat, May 14, 2011 at 8:11 AM, Alexander Chemeris <address@hidden> wrote:

On Fri, May 13, 2011 at 14:25, Tom Rondeau <address@hidden> wrote:
> On Fri, May 13, 2011 at 11:12 AM, Yang <address@hidden> wrote:
>>
>> Hi all,
>> I am working on the implementation of dynamic spectrum access with
>> gnuradio and usrp2. I modified usrp_spectrum_sense for usrp2 to do the
>> sensing job. However, I find the sensing speed is intolerably slow, which is
>> about 1s for 1MHz.
>
> Yang,
> Considering that the USRP2 can sample 25 MHz, you should be able to capture
> that bandwidth instantaneously.

Note, that while USRP2 can sample 25MHz, you probably can't receive
that much in your PC. I'm working with USRP N210 and having troubles
with receiving even 16 MSPS.

--
Regards,
Alexander Chemeris.

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