From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Berg Subject: Re: MCS field - STBC and Ness Date: Thu, 05 Jul 2012 11:12:30 +0200 Message-ID: <1341479550.4455.36.camel@jlt3.sipsolutions.net> References: <4FAC5DE0.90708@superduper.net> <4FACBA13.9040509@neratec.com> <4FAD41E4.3090803@superduper.net> <4FAD43F0.20807@superduper.net> <1336761346.8739.3.camel@jlt3.sipsolutions.net> <4FADE69F.9040100@superduper.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FADE69F.9040100-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org> Sender: radiotap-owner-sUITvd46vNxg9hUCZPvPmw@public.gmane.org To: Simon Barber Cc: Wojciech Dubowik , radiotap-sUITvd46vNxg9hUCZPvPmw@public.gmane.org List-Id: radiotap@radiotap.org On Fri, 2012-05-11 at 21:27 -0700, Simon Barber wrote: > Another slight tweak - I think STBC is more commonly used than Ness (as > witnessed by Wojciech's interest), so give STBC the simpler encoding. I > believe Ness is used for beamforming soundings. > > Spec would look like this: > > known definition > 0x01 bandwidth > 0x02 MCS index known (in mcs part of the field) > 0x04 guard interval > 0x08 HT format > 0x10 FEC type > 0x20 STBC > 0x40 Ness - Number of extension spatial streams is known > 0x80 Ness2 - bit 1 (MSB) of Number of extension spatial streams. > > The flags field is any combination of the following: > > flag definition > 0x03 bandwidth - 0: 20, 1: 40, 2: 20L, 3: 20U > 0x04 guard interval - 0: long GI, 1: short GI > 0x08 HT format - 0: mixed, 1: greenfield > 0x10 FEC type - 0: BCC, 1: LDPC > 0x60 STBC - 0, 1 or 2: number of STBC streams > 0x80 Ness - bit 0 (LSB) of Number of extension spatial streams. > > What should I do to advance this as an approved radiotap extension? I suppose you already have patches for wireshark for this? I can help you out with a patch for the Linux kernel as an example producer of this, and then I think just repost it to the list again to leave some more discussion time. johannes