RE: [Discuss-gnuradio] 802.11 and Bluetooth

[Dheeraj S. Aralumallige]

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’m just interested in detecting the presence of any of these signals in the environment. I don’t want to transfer any data/packets using SDR. I just need to detect the presence or absence of a signal.

Please help me regarding this.

Thanks again…

 

Regards,

Dheeraj

 

-----Original Message-----
From: address@hidden [mailto:address@hidden On Behalf Of Tom Rondeau
Sent: Wednesday, December 06, 2006 12:01 AM
To: address@hidden
Subject: [Discuss-gnuradio] 802.11 and Bluetooth

 

I've seen a number of questions about these issues in the past couple of

days, so I'm addressing this from my own knowledge.

 

Can we detect Bluetooth and WiFi with GNU Radio?

 

I'm making two assumptions: we're using the USRP and WiFi/802.11 is

specifically addressing 802.11a/b/g.

 

The answer is no. The bandwidth is too large for the system to currently

handle. If you tune the GNU Radio to the center frequency of an 802.11

channel, you'll see what looks like a rise in the noise floor (and, under

these conditions, it really is a rise in the noise) when there is a

transmission.

 

Bluetooth signals hop from 2.402 - 2.480 MHz; 79 1 MHz channels at a rate of

1600 hops per second. The GNU Radio cannot look a the entire band all at

once, so if you look at a particular slice (~4 MHz) of spectrum, you might

catch a glimpse of a signal every now and then, unless you can plug in the

right frequency hopping sequence (I think I have both MATLAB and C++ code to

do this, buried somewhere, but then you'd need the master address (easy) and

its clock (difficult) to do it; and I'm not sure if the USRP's can change

frequency and settle fast enough for this).

 

If you have some 1 or 2 Mbps 802.11 devices to use, the BBN guys have done

work on receiving those (search the list, it's been addressed a number of

times in the past).

 

Hope this clears a bit up,

Tom

 

 

 

 

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