MU MIMO VS SU MIMO

[sfx2000]

I'm not so sure, because with TxBF even with MU-MIMO you are still getting the antenna gain of 1-4 dBm - those 2 streams sent out to 2 clients comes simultaneously come out (in a 4x4:4:3 radio from) THREE antenna. To be clear - 2 streams are sent out out of all THREE antenna simultaneously using pretty complicated TxBF maths, so I expect the client will be able to decode the signal nearly as well as SU-MIMO.

yes, but... an MU stream (frame set) is quasi-orthoganal by it's very nature, so a higher risk of a client having error as opposed to a standard SU frame - and one still gets the benefit of TxBF, and the additional benefit of STBC's (4*1 is a permitted config there with a four radio AP config). The TxBF gives around 1-2 dB gain on the downlink, STBC adds a couple of dB coding gain - enough so that the single client might actually be able to get one step higher MCS value...

Have to be careful on the EIRP (dBm) values, as some regulatory domains have issues (still being worked on last I checked) with regards to omni vs. TxBF and total EIRP limits...

 

[thiggins]

Keep in mind 4x4 MU routers can still produce higher total throughput with more than 3 MU STAs.

http://www.smallnetbuilder.com/wireless/wireless-features/32898-is-mu-mimo-ready-for-prime-time

 

[sfx2000]

Keep in mind 4x4 MU routers can still produce higher total throughput with more than 3 MU STAs.

Doesn't mean they will - much depends on the client mix and environment - this ain't my first rodeo with TxBF or MU...

 

[thiggins]

Doesn't mean they will - much depends on the client mix and environment - this ain't my first rodeo with TxBF or MU...

Same can be said for any wireless mix.

My point is there is no wall at 3 STAs

 

[sfx2000]

Same can be said for any wireless mix.

My point is there is no wall at 3 STAs

Never suggested there was - just that many models/simulations so far favor MU in good conditions - having been there with TxBF and then with MU, real world doesn't always align with simulators or models...

 

[ulaganath]

How this practically for us . Isnt this good for us.

Will have mix of old ie current SU-mimo client and future upgrade of smartphone and lappies with MU-mimo. Still the network handle both