VHT 160Mhz and nss related config.

[Ben Greear]

On 02/12/2017 02:56 AM, Sebastian Gottschall wrote:
> Am 11.02.2017 um 20:38 schrieb 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
>>
>> 160Mhz is really implemented as 80+80 internally it seems, so what I meant is that
>> 160Mhz or 80+80 both have the 2x2 restriction.
> since i have a older fw source. can you give me a hint where you found a indication that its just 2x2?

Look for:

MAX_SPATIAL_STREAMS_SUPPORTED_AT_160MHZ

Thanks,
Ben

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