How 802.11 ac wave 2 MU-MIMO works

[FES]

Hi,

we have a question about how MU-MIMO works. 

In our aps infraestructure (3915 and 3912 models) we only have 20MHz channels to avoid overlaping channels. 

The aps are 2x2:2MU-MIMO. ¿our question is?

With a 20MHz using one antenna the aps can una 2 spatial streams to send trafic to 2 MU-MIMO clients? Or this only works when we have 40MHz Channel with 2 antennas working?

Sorry for the english 

[FES]

Hi Chris,

in addition to this… I think in a building that have classrooms. We install one AP for each class 2x2:2MU-MIMO… I have speak with other wireless stuff and was talking about the spatial streams. We only can uso different spatial streams if the users not are phisical in the same place, in order to use beanforming to use this different 2 spatial streams.

If this case is true 802.11ac wave 2 and 802.11ax dont have more possibilities than 802.11ac wave1. Also we need that the users have devices using 802.11ac wave 2 ( more battery usage) or 802.11ax (I dont know devices in the market at now)…

This thoughts are in order to have a ROI of the wifi infraestructure 802.11ac wave2.. I think is very difficult to justify in our scenario. 

Thanks in advance for the info.

[ckelly]

Correct.  MU-MIMO will be limited by the number of spatial streams that the AP supports.  So if your AP model is a 2x2:2, it only supports 2 spatial streams...and therefore can only potentially transmit at the same time to 2 wireless clients.

The channel width (20MHz/40MHz doesn’t have anything to do with this limitation)

[FES]

OK thanks,

Then, using 802.11ac wave 2, 4x4:4 MU-MIMO APs, with a ssid with 20Mhz we can serve 3 spatial streams to 3 different MU-MIMO clients 1x1:1?

Also , we can serve 3 clients: 2clientes 1x1:1 and other 2x2:2?

Thanks in advance