From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from rn-out-0910.google.com ([64.233.170.190]:5331 "EHLO rn-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751725AbZBKVl0 (ORCPT ); Wed, 11 Feb 2009 16:41:26 -0500 Received: by rn-out-0910.google.com with SMTP id k40so448374rnd.17 for ; Wed, 11 Feb 2009 13:41:25 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <2d14e2ca0902110900r7f0b84e4k7be81827187c434@mail.gmail.com> References: <2d14e2ca0902110900r7f0b84e4k7be81827187c434@mail.gmail.com> Date: Wed, 11 Feb 2009 13:41:25 -0800 Message-ID: <43e72e890902111341l36bd40c8o9d54515e8b06e603@mail.gmail.com> (sfid-20090211_224131_552427_AB50FA90) Subject: Re: [ath9k-devel] Radar Detection and DFS status From: "Luis R. Rodriguez" To: mementux Cc: linux-wireless@vger.kernel.org, ath9k-devel@lists.ath9k.org, Michael Green Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: 2009/2/11 mementux : > Hi! > > I would like to make an outdoor radio link at 5GHz between my house and one > of my neighbors. Because I live near an airport, I've looked for European in > force regulation regarding radar detection. I've discovered that ETSI has > released a new normative on Dicember 2008 (EN 301 893 v1.5). This normative > requires that WLAN devices with DFS capability must detect pulse width down > to 0.8us across the bands from 5250 to 5350MHz and from 5470 to 5725 MHz; > moreover they must detect staggered Pulse Repetition Frequency (PRF) radars > with 3 PRF value (I don't excactly know what it means). > > I have two devices with Atheros 5414 radio module, so I've looked for > support of radar detection (and 802.11h) in madwifi driver. I've seen that > the -dfs branch supports the EN 301 893 v1.4.1 and it implements 802.11h > protocol. Looking into the madwifi-dfs code I've seen that the hardware does > the pulse detection and the driver detects the radar recognizing the pulse > patterns (ath/if_ath_radar.c and ath/if_ath_radar.h). > > Because the pulse detection is done in hardware, I suppose that for > detecting pulse width down to 0.8us I need radio modules with newer chipset > like AR9xxx. Is it right? Can't I use my AR5414 radio modules? > So, I've searched in the code of ath9k and mac80211 but I don't find any > implementation of radar detection and 802.11h. Am I wrong? I've read on > http://wireless.kernel.org/en/users/Drivers/ath9k that 802.11h is a feature > of ath9k driver (and consecutively of mac80211, right?). > > I there any way to make an outdoor radio link at 5GHz compliant to the > European regulation with Linux? :-) mac80211 or ath9k does not yet have radar detection support so therefore no mac80211 driver will allow you to use any beaconing mode (AP | IBSS | Mesh) mode on DFS channels yet. Note that not all 5 GHz channels require radar detection though so you could try using one of the non-DFS channels. Check 'iw list' for that. ath9k STA should work with DFS but I didn't work on that myself so will leave someone else to comment on that. Luis