[ath9k-devel] Ath9k MIMO Performance versus Proprietary Drivers

[Luis R. Rodriguez <lrodriguez@atheros.com>]

On Fri, Feb 26, 2010 at 12:45:02PM -0800, Galen wrote:
> 
> On Feb 26, 2010, at 8:45 AM, Luis R. Rodriguez wrote:
> 
> > On Thu, Feb 25, 2010 at 09:37:12PM -0800, Galen wrote:
> >> On Feb 24, 2010, at 4:39 PM, Luis R. Rodriguez wrote:
> >>> MRC is supported on all 11n chipsets, but not for cck rates.
> >>> TX beamforming is only supported on the shiny new AR93xx
> >>> chipsets. TX beamforming seems to have been supported on
> >>> some old legacy chipset but there is no code to support it
> >>> and I wouldn't bother trying.
> >>> 
> >>> Luis
> >> 
> >> 
> >> Luis - can you comment on the MRC implementation? Is this entirely
> >> invisible to ath9k, or is this implemented / supported in software?
> > 
> > No, frankly this is the first time I read about MRC.
> > I just poked a few guys here about MRC and got the clarification
> > above.
> 
> Right - so the MRC functionality is in the chip's DSP and entirely
> invisible to the software? Yes? Just being 100% clear here...

Beats me. I haven't dealt with MRC at all in software so I guess.

> >> And to be clear, you think the 802.11n chipsets before the
> >> AR9300 *do not* include TxBF at all? Not that it simply isn't
> >> supported by the drivers?
> > 
> > Only a legacy (802.11g) end of life'd device had some form
> > of Tx beamforming, but that's not even supported and its easier
> > to just assume no chipset supports it other than the shiny
> > new AR93xx family.
> 
> Right - and as discussed, TxBF has less benefit than with 802.11n.

Oh?

> Since then, I have looked at some Matlab simulations here and seeing
> that 2 antenna MRC can slightly outperform 2 antenna TxBF. 

Good to know, can you publish your results while at it.

  Luis