Why is TxBF limited to the R710?

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I recently got an R710, and in playing around with it, I've noticed that some of my devices are using a MCS rate that includes "/2/BF", which seems like it's using 4 radio chains to do 2-stream TxBF in addition to BeamFlex? Very cool :)

I also noticed that the support info for the R710 on 9.12 shows a lot of info about TxBF sounding frames and such, which is missing from the R600/R700. Is there a particular reason that the R710 supports TxBF but the R600/R700 does not?

FWIW, I'm also noticing that the R710 is able to deliver good 802.11ac speeds to Wave 1 devices at a longer range. Even through 2 walls, I'm seeing 300mbit on a 3x3:3 Wave 1 client when an R600 just a few feet away can only deliver 400-450mbit to the same client. Looks like it's a compelling upgrade even if you don't have Wave 2 capable clients!
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John D, AlphaDog

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Posted 2 years ago

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Sean

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The r710 is the first Wave 2 compliant AP that Ruckus has released.

As wave 2 is hardware dependent the r600 and r700 will never be Wave 2 compliant as they are not a modular AP.

I've had a r710 also for around 4 months now, and I am still waiting on Airtime Fairness to be released for the 5GHz so I can put in the chamber, oh yeah and a wave 2 client emulator blade from Ixia.
(Edited)
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John D, AlphaDog

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I was under the impression that Txbf is not specific to wave 2, and a lot of competing equipment already supports 802.11ac beam forming in their Wave 1 products.
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Sean

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Like I said its hardware dependent, and the 4x4 element is one part that you need to be looking at.

As you may already know you need double the amount of TX antennae as you have spatial streams; tradeoff between txbf and spatial multiplexing as you cant use both on the same TX antennae.

Note: All previous iterations have either been 2x2 or 3x3 and therefore are not 802.11ac wave 2 compliant as you need 4 spatial streams to be compliant and therefore you need a 4x4 array.
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John D, AlphaDog

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There's of course a tradeoff between spatial streams versus TxBF, but the 2x2 and 3x3 AP's are more than capable hardware-wise of forming 1-SS BF patterns, which are fine for mobile clients, many of which are one-stream anyway. In fact, the data sheets for the R500, R600, and R700 all have the statement "Transmit Beamforming Capable" on their product info pages. Wave 2 is not a requirement for transmit beamforming, as Aruba and everyone else using Broadcom AP chipsets, including cheap Netgear equipment, sport transmit beamforming on their 802.11ac wave 1 3x3:3 AP's.

I'm simply asking why the firmware for these units seem to have no indication that they're capable of generating sounding frames for TxBF? I'm fine if TxBF's tradeoffs never win in my environment — that's perfectly fine. But it seems like Ruckus has been getting very loose lately with advertising capabilities of their AP that never materialize, or are actually coming soon. Like airtime fairness, QoS, and heuristic classification all seem to be inactive / coming soon on the 802.11ac AP's but are advertised on the datasheets. 
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John D, AlphaDog

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Sounding frames were even defined for 802.11n, and as far as I can see from the 802.11ac spec, implicit and explicit sounding are simply described as "optional" and are not confined to Wave 2 only. It could be that the hardware for Ruckus Wave 1 AP's don't support 802.11ac transmit beamforming and that was just added for Wave 2... but in which case, what does Ruckus mean when the data sheets for R500, 600, and 700 all say "Transmit Beamforming Capable"?

There are specific sounding frames that appear specific to DL MU-MIMO, but that's another story, and of course, I don't expect support those on a wave 1 AP.
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John D, AlphaDog

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http://community.arubanetworks.com/t5/Technology-Blog/11ac-Beamforming-Makes-the-Dog-Rollover/ba-p/1...


In fact, Aruba has had 802.11ac beamforming since wave 1, and implied that it's a limitation of the Wave 1 QCA chipset vs the Wave 1 Broadcom chipset that transmit beamforming isn't supported. Well, I guess that answers my question.
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Sean

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There are specific sounding frames that appear specific to DL MU-MIMO, but that's another story, and of course, I don't expect support those on a wave 1 AP.
We are on the same page then, as your orginal question was regarding TxBF sounding frames, which made me think your question was regarding Wave 2:
I also noticed that the support info for the R710 on 9.12 shows a lot of info about TxBF sounding frames and such, which is missing from the R600/R700. Is there a particular reason that the R710 supports TxBF but the R600/R700 does not?
As for Aruba... there not my cup of tea.
(Edited)
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John D, AlphaDog

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No worries — and don't get me wrong, I'm not implying that Aruba is better, and as the comments show, their testing results were not replicated by some of the commenters.

I'd rather have BeamFlex+ over 802.11ac TxBF any day, but it sounds like the best-of-both-worlds is having both, at least that was heavily stressed in the R710 marketing materials.
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Sean

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Same here, cant wait until all the good stuff comes to the fold on the r710... tic toc