Re: [Discuss-gnuradio] 802.11 and Bluetooth

[Thomas Schmid]

On 12/5/06, Dheeraj S. Aralumallige <address@hidden> wrote:
> Hi !!
>
>
>
> Thank you very much for the help!!!
>
> But still I have one question. (See the highlighted part)
>
> Is there any example program to just detect the presence of wi-fi or
> Bluetooth.

I think Tom answered this question really well. No, it is currently
not possible to detect bluetooth because the bandwidth of the USRP is
not high enough to cover the whole 2.4 GHz ISM band (~80 MHz) at once.
For Wi-Fi, it is possible as long as you are only interested in one
channel.

Nevertheless, there is a spectrum sweep example
(gnuradio-example/usrp/usrp_spectrum_sense.py). This application can
sense a large bandwidth, but not in real time! It can do a sweep over
a very large frequency range, but it will very likely not be able to
detect bluetooth (since it is frequency hopping) nor 802.11b/g since
this will most likely just look like noise. Anyway, it is difficult to
just detect wi-fi without trying to decode it, since it is not a
continuous signal, i.e., packet oriented. Therefore, you won't have a
nice peak in your fft, compared to a radio broadcast channel. I
suggest you look at the wi-spy (http://www.metageek.net/) if you just
want to detect bluetooth or wi-fi. That might be a cheaper and simpler
solution to your problem.

Hope that helps. Cheers,

Thomas