Re: [Discuss-gnuradio] Trigger 5GHz-WLAN radar detection?

[Marcus Müller]

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 21:47, 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.
>
>
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