Date: Wed, 29 Oct 2014 13:33:16 +0400 From: Sergey Ryazanov <ryazanov.s.a@gmail.com> To: Graf Monika <grafmon@student.ethz.ch> Cc: "freebsd-wireless@freebsd.org" <freebsd-wireless@freebsd.org> Subject: Re: Time-of-flight positioning - Atheros Message-ID: <CAHNKnsTo5Pt4tvxnL4MJKsUsjGc-fYQMXdi3%2BDzBvvJZNxwYrg@mail.gmail.com> In-Reply-To: <1E0B1592-5212-4D65-8F08-344EC215EA47@student.ethz.ch> References: <1E0B1592-5212-4D65-8F08-344EC215EA47@student.ethz.ch>
next in thread | previous in thread | raw e-mail | index | archive | help
Hi Monika, 2014-10-29 11:44 GMT+03:00 Graf Monika <grafmon@student.ethz.ch>: > Hello Everyone > > I am currently at a project where I am using Atheros Chipsets AR9590 with the ath9k driver. > It's a bit strange to ask questions about linux driver in freebsd-wireless mailing list. Just in case, there are two mailing lists for ath9k: ath9k-devel and linux-wireless. > I am wondering how the time-of-flight information can be retrieved per packet in most recent Atheros chipsets. Is it required a proprietary HAL version ? > If you need a round-trip-time: take a tx timestamp from tx-complete descriptor of data frame, then take a timestamp from received ACK frame and then compute the time. To get received ACK frames from NIC you should enable control frames receiving in Rx filter. If you need more details about descriptor format or time of timestamp capture, then may be Adrian could help. BTW, a month ago or so, Lorenzo Bianconi added a dynamic ACK timeout estimation to the ath9k, based exactly on round-trip-time computation. -- BR, Sergey
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAHNKnsTo5Pt4tvxnL4MJKsUsjGc-fYQMXdi3%2BDzBvvJZNxwYrg>