This is some quite good information, thank you very much!
We need to set up some 5GHz-Links, and therefore I would like to test if the link partners reliably find each other again after a radar detection. Ralph. From: discuss-gnuradio-bounces+ralph=schmid....@gnu.org [mailto:discuss-gnuradio-bounces+ralph=schmid....@gnu.org] On Behalf Of Jawad Seddar Sent: Friday, 08 January, 2016 23:24 To: GNURadio Discussion List Subject: Re: [Discuss-gnuradio] Trigger 5GHz-WLAN radar detection? I managed to find an old document that details the output from the driver and the pulses I generated. I tried it with 2 different pulse characteristics : - Pulse width of 15 μs and PRF equal to 1000 Hz - Pulse width of 15 μs and PRF equal to 3000 Hz Image below details the second signal (PRF = 3kHz). Images intégrées 1 This is some log when detecting the first signal Images intégrées 2 This is some log when detecting the second signal Images intégrées 3 You can see the driver recognizes the PRF quite well. I hope this helps a bit, Jawad 2016-01-08 23:13 GMT+01:00 Jawad Seddar <jawad.sed...@gmail.com>: Hi Ralph, I did this 2 and half years ago and I basically followed the directions in pages 60-61 of the ETSI document linked by Marcus to generate the signals. By watching the channel on which the WiFi card was operating, I generated the signal at the right frequency and I could see the card changing frequencies. I could then access some log files that detailed why the frequency change happened (In this case it was saying that it had detected a radar with a given Pulse Repetition Frequency and gave some details about the detected signal). I believe I was using the ath5k drivers (see madwifi-project). Regards, Jawad 2016-01-08 22:56 GMT+01:00 Marcus Müller <marcus.muel...@ettus.com>: Hi Ralph, hm; depends, I think. So, there's two things: If you're referring to a channel switch announcement, that can be part of a management frame [1]. But I think it can also be part of a beacon frame. Or a probe response frame. Luckily, 802.11 is not confusing the least. Blind guess is that you should look into airprobe-ng's "aireplay" program and see whether it can synthesize such a frame. Basically, you should be able to forge at least beacon frames, which might be helpful as soon as you deauthenticated a station; a very common attack. More likely, even, is that you're talking about mimicking a fake radar. I guess the appropriate way to do that is probably sending something that looks sufficiently close enough to a chirp to the OFDM demod, I think. I'm too lazy to read this myself :D, so go and read 5.3.8.1 and following of ETSI EN 301 893 [2], and refer to a trustworthy free and open WiFi card driver (hint hint: atheros 9k, dfs_pattern_detector.c). Best regards, Marcus [1] https://mentor.ieee.org/802.11/dcn/10/11-10-0097-06-00ae-management-frame-analysis.xls [2] https://www.etsi.org/deliver/etsi_en/301800_301899/301893/01.05.01_60/en_301893v010501p.pdf On 08.01.2016 21 <tel:08.01.2016%2021> :47, Ralph A. Schmid, dk5ras wrote: > Hi, > > Does anybody know how a signal must look to trigger a 5 GHz WLAN for a > frequency change? I intend testing this feature by transmitting a radar-like > signal with gnuradio, but for this I should know how this detection works, > how such a signal does look :) > > Ralph. > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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