VHT 160Mhz and nss related config.

[Ben Greear]

On 02/11/2017 10:21 AM, Sebastian Gottschall wrote:
> Am 11.02.2017 um 18:58 schrieb Ben Greear:
>> On 02/10/2017 08:37 PM, Adrian Chadd wrote:
>>> On 10 February 2017 at 20:22, Sebastian Gottschall
>>> <s.gottschall at dd-wrt.com> wrote:
>>>> i really can't believe this. if this is true the  160 mhz mode would not
>>>> make any sense.
>>>> the maximum tx / rx rate for 4x4 vht80 and 2x2 vht160 is identical. so
>>>> vht160 would not increase performance in any way
>>>
>>> Well, if it can also do 2x2 MU-MIMO at 160MHz then it can be a
>>> perfectly fine STA to a 4x4 160MHz MU-MIMO chip that can actually
>>> transmit 2x2 rates to different MU-MIMO peers.
>>>
>>> That's the outstanding question I have - is it like, 2x2 MU only, or
>>> is it say, 2 concurrently different spatial stream 2x2 MU? Ie, can you
>>> have 2 peers, different VHT spatial groups (or 4 peers, 1 spatial
>>> group each) all going at the same time?
>>>
>>> I'm .. not even sure how you're supposed to cleanly negotiate that you
>>> can do 4NSS in VHT80 but 2NSS in VHT160 to a peer... that only makes
>>> sense if you're doing lots of 1NSS and 2NSS MU-MIMO peers..
>>
>> I think using the max-rx-rate logic might could imply this, but I am not sure
>> many drivers fill this out properly.
>>
>> Looks like a mess waiting to happen to me.
>>
>> Even if you can do 1x1 160Mhz MU-MIMO to two stations, and I am not certain you
>> can since in 80Mhz you can only do a 1x1 and a 2x2 (not two 2x2).
>>
>> So, from what I know currently, 80+80 is not that useful on the 9984 NIC...
> never tried 80+80 since i need to enhance the channel logic alot in my firmware code to handle it. would be great enough if vht160 would work as expected and
> i'm not sure right now if it really works, even if the interface initialized correctly it assocs only with vht80

Looks like it is working with the hack I posted:

Station 04:f0:21:2e:49:65 (on wlan2)
	inactive time:	0 ms
	rx bytes:	64902998
	rx packets:	37918
	tx bytes:	64760298
	tx packets:	42239
	tx retries:	0
	tx failed:	0
	signal:  	-43 dBm
	signal avg:	-42 dBm
	tx bitrate:	1053.0 MBit/s VHT-MCS 6 160MHz VHT-NSS 2
	rx bitrate:	1560.0 MBit/s VHT-MCS 8 160MHz short GI VHT-NSS 2
	authorized:	yes
	authenticated:	yes
	preamble:	long
	WMM/WME:	yes
	MFP:		no
	TDLS peer:	no
	connected time:	156 seconds

Thanks,
Ben


-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com