Date: Tue, 21 Aug 2012 22:39:07 -0700 From: Adrian Chadd <adrian@freebsd.org> To: "Wright, Brett" <Brett.Wright@cooperindustries.com> Cc: freebsd-wireless@freebsd.org, Kim Culhan <w8hdkim@gmail.com> Subject: RE: Atheros DFS radar detection Message-ID: <CAJ-VmomzwSE5sgNYpdMgYeOtNhU1XQ7_v85FxFhtRSRqf06Ljg@mail.gmail.com> In-Reply-To: <475A4E02EFF4724A9E58F55A56AC13160661E6AC@APEVS1.ap.ci.root> References: <CAKZxVQU-%2BW9AP4a9W0PGyLmBOa1GVOrGcLC8bp5zW_=K%2Bv3tHA@mail.gmail.com> <475A4E02EFF4724A9E58F55A56AC13160641D618@APEVS1.ap.ci.root> <CAKZxVQWeOnw_kZWzuXfHSS-ssQfGVG=ybYK%2B%2B8EaqnFVe-rLpg@mail.gmail.com> <CAJ-Vmon=NfyZW9vJRSNxTLZvJhobeCP-S1O3TxopNzArWunCCQ@mail.gmail.com> <475A4E02EFF4724A9E58F55A56AC13160661E6AC@APEVS1.ap.ci.root>
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Oh. Disable ANI too. Adrian On Aug 21, 2012 10:15 PM, "Wright, Brett" <Brett.Wright@cooperindustries.com> wrote: > > -----Original Message----- > > From: adrian.chadd@gmail.com [mailto:adrian.chadd@gmail.com] On Behalf > > Of Adrian Chadd > > > > Brett, did you have any luck? > > > > I'll be in a position to test out with some AR5212 era NICs this week. > > > > Adrian > > > > Hi Adrian, > > I have been mucking around with the radar parameters for several days > now. In order to get reasonably low levels of false detects I need very > aggressive (at least I *think* they are aggressive) values for the radar > parameters. For example: > > FIRPWR: -33 > RRSSI: 45 > HEIGHT: 28 > PRSSI: 22 > INBAND: 6 > > However, the meaning of these parameters is still a little unclear to > me. I have read the patent document many times but there is still a lot > of information I do not know. I would be prepared to bet that Atheros > has documentation describing the above parameters with a lot more > clarity. For example , just to pick one of the parameters FIRPWR: > According to the comment for this field it is a threshold that the > signal power must exceed, but it's default value is -41dBm. Now -41dBm > is VERY strong! Also, my experimentally derived value of -31dBm is way > stronger still. Certainly in my test environment the strongest signals > are around -55dBm (way weaker than either of these values). This really > highlights to me that I am "missing" something... > > Also, the parameter I found makes the biggest difference to my false > detects is RRSSI which is "the threshold that the RSSI must exceed when > AGC is OK..." etc. Is this a SNR? If so 45dB (my setting for this > parameter) with a noise floor around -95dBm would equate to an absolute > RSSI of -50dBm. Am I reading this correctly? And if it is an SNR, then > why is FIRPWR apparently an actual RSSI (i.e. absolute level). Is > everything other than FIRPWR an SNR? > > Finally, I haven't yet taken the next step of actually injecting radar > pulses, but my suspicion is that with such aggressive parameters that > actual radar detection according to the regulatory test patterns will > fail. > > I do realize that the difficulties I'm having are due to my lack of > information and understanding, however any light you may be able to shed > would be greatly appreciated. > > Thanks > Brett > >
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