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From: Simon Barber <simon-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
To: radiotap-sUITvd46vNxg9hUCZPvPmw@public.gmane.org,
	wojciech.dubowik-ASv44eHyqLVBDgjK7y7TUQ@public.gmane.org
Subject: MCS field - STBC and Ness
Date: Thu, 10 May 2012 17:31:28 -0700
Message-ID: <4FAC5DE0.90708@superduper.net> (raw)

Hi all,

I am writing a Wireshark extension to visualise 802.11 frames on a 
timeline. In order to do this I need to be able to calculate the 
duration from start of TX to end of TX for each frame.

For 802.11n I need to know the number of HT-DLTF and HT-ELTF training 
symbols that are sent in the header - I have everything else needed to 
calculate the duration. Given the MCS and the STBC and the Ness (Number 
of extension spatial streams) I can calculate the number of training 
symbols.

Both STBC and Ness are encoded in the HT-SIG transmitted at the start of 
each HT frame.

The current proposal (or has it not yet been accepted?) for STBC 
allocates just 1 bit - but the STBC field can have values or 0, 1 or 2.

Ness can be 0-3, so the remaining 2 bits could be allocated to Ness, but 
this does not solve the problem of how to encode the modes with 2 
spatial streams and 2 additional streams for STBC.

Does anyone know what current hardware supports - STBC values or 0,1,2? 
Ness values of 0-3?

Any suggestions for how to convey these

Simon

             reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-11  0:31 Simon Barber [this message]
     [not found] ` <4FAC5DE0.90708-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
2012-05-11  7:04   ` Wojciech Dubowik
     [not found]     ` <4FACBA13.9040509-ASv44eHyqLVBDgjK7y7TUQ@public.gmane.org>
2012-05-11 16:44       ` Simon Barber
     [not found]         ` <4FAD41E4.3090803-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
2012-05-11 16:53           ` Simon Barber
     [not found]             ` <4FAD43F0.20807-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
2012-05-11 18:35               ` Johannes Berg
     [not found]                 ` <1336761346.8739.3.camel-8upI4CBIZJIJvtFkdXX2HixXY32XiHfO@public.gmane.org>
2012-05-12  4:27                   ` Simon Barber
     [not found]                     ` <4FADE69F.9040100-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
2012-07-05  9:12                       ` Johannes Berg
     [not found]                         ` <1341479550.4455.36.camel-8upI4CBIZJIJvtFkdXX2HixXY32XiHfO@public.gmane.org>
2012-11-01  0:22                           ` Simon Barber
     [not found]                             ` <5091C0BC.4040305-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
2012-11-02  0:24                               ` Simon Barber
     [not found]                                 ` <509312DB.7070100-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
2012-11-05 14:35                                   ` Johannes Berg
2012-11-17  6:32                                   ` Standardisation - adding 2 bit STBC and Ness to MCS Simon Barber
2012-07-04 17:06   ` MCS field - STBC and Ness David Young

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