From owner-freebsd-wireless@FreeBSD.ORG Thu Oct 30 06:57:22 2014 Return-Path: Delivered-To: freebsd-wireless@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 05BD021F; Thu, 30 Oct 2014 06:57:22 +0000 (UTC) Received: from edge20.ethz.ch (edge20.ethz.ch [82.130.99.26]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "edge20", Issuer "edge20" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 93383BFB; Thu, 30 Oct 2014 06:57:21 +0000 (UTC) Received: from CAS11.d.ethz.ch (172.31.38.211) by edge20.ethz.ch (82.130.99.26) with Microsoft SMTP Server (TLS) id 14.3.195.1; Thu, 30 Oct 2014 07:57:10 +0100 Received: from MBX22.d.ethz.ch ([fe80::b5f8:e932:7440:95ef]) by CAS11.d.ethz.ch ([fe80::ecc9:4e2d:b26b:1614%10]) with mapi id 14.03.0195.001; Thu, 30 Oct 2014 07:57:13 +0100 From: "Graf Monika" To: Adrian Chadd , Sergey Ryazanov Subject: AW: Time-of-flight positioning - Atheros Thread-Topic: Time-of-flight positioning - Atheros Thread-Index: Ac/zVIXE+2jNKf85S8qUgq/JjldDPf///OwAgACXKgCAAN+V8g== Date: Thu, 30 Oct 2014 06:57:12 +0000 Message-ID: <2CCC302EA38F004C899D788D1F3438D51FA025CA@MBX22.d.ethz.ch> References: <1E0B1592-5212-4D65-8F08-344EC215EA47@student.ethz.ch> , In-Reply-To: Accept-Language: de-CH, en-US Content-Language: de-CH X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [62.202.7.132] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "freebsd-wireless@freebsd.org" X-BeenThere: freebsd-wireless@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "Discussions of 802.11 stack, tools device driver development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Oct 2014 06:57:22 -0000 thanks for your answers!:)=0A= =0A= Adrian, could you specify a little bit more, how that I get out the PHY tim= estamp?=0A= =0A= Thank you!=0A= =0A= Monika=0A= ________________________________________=0A= Von: adrian.chadd@gmail.com [adrian.chadd@gmail.com]" im Auftrag von &= quot;Adrian Chadd [adrian@freebsd.org]=0A= Gesendet: Mittwoch, 29. Oktober 2014 19:34=0A= An: Sergey Ryazanov=0A= Cc: Graf Monika; freebsd-wireless@freebsd.org=0A= Betreff: Re: Time-of-flight positioning - Atheros=0A= =0A= Oh, I asked him to. I don't mind which list he's asking for hardware help o= n.=0A= =0A= =0A= On 29 October 2014 02:33, Sergey Ryazanov wrote:= =0A= > Hi Monika,=0A= >=0A= > 2014-10-29 11:44 GMT+03:00 Graf Monika :=0A= >> Hello Everyone=0A= >>=0A= >> I am currently at a project where I am using Atheros Chipsets AR9590 wit= h the ath9k driver.=0A= >>=0A= > It's a bit strange to ask questions about linux driver in=0A= > freebsd-wireless mailing list. Just in case, there are two mailing=0A= > lists for ath9k: ath9k-devel and linux-wireless.=0A= >=0A= >> I am wondering how the time-of-flight information can be retrieved per p= acket in most recent Atheros chipsets. Is it required a proprietary HAL ver= sion ?=0A= >>=0A= > If you need a round-trip-time: take a tx timestamp from tx-complete=0A= > descriptor of data frame, then take a timestamp from received ACK=0A= > frame and then compute the time. To get received ACK frames from NIC=0A= > you should enable control frames receiving in Rx filter. If you need=0A= > more details about descriptor format or time of timestamp capture,=0A= > then may be Adrian could help.=0A= =0A= The RX timestamp is from the MAC, not the PHY. So it's an OK estimate,=0A= but for metre and sub-metre accuracy you still need to get the=0A= original PHY timestamp. IIRC the timestamps are microsecond accurate,=0A= which limits your actual distance calculation.=0A= =0A= Now, the AR9380 and later chips do have some stuff to pull out the PHY=0A= timestamp and some information about the leading edge of the received=0A= frame.=0A= =0A= > BTW, a month ago or so, Lorenzo Bianconi added a dynamic ACK timeout=0A= > estimation to the ath9k, based exactly on round-trip-time computation.=0A= =0A= That was pretty cute.=0A= =0A= =0A= -adrian=0A=