Does beamforming always use MU-MIMO in 5G?
It can be SU-MIMO or MU-MIMO.
We need to activate MU-MIMO using switch parameter.
Once MU-MIMO activated then users coming in pairing depend on below factors:
- Spatial distance
- CQI reported
- Number of layers configured
If condition satisfied then only UE come in pairing called MU-MIMO.
By spatial distance I mean correlation < 1, i.e. UE are separated not clustered.
No, there is beamforming also for SU-MIMO.
Beamforming always mean number of ssb > 1.
If you have single SSB then it’s not beamforming.
That means it can be both, right?
Yes both but remember without activation of MU-MIMO it will not work.
Default always SU-MIMO.
Normally what is recommended?
Should we enable MU-MIMO?
For high Traffic with PRB utilization average over 80%.
Yes for PRB saving recommend, but Throughput can dip.
Seen with MU-MIMO big struggle to get user Throughput gain.
Pre/post kpi’s need to capture carefully to show gain.
So when MU-MIMO is not enabled, PDSCH/PDCCH resources will be divided among the beams?
Here are some god stats for LTE 16 PDSCH layers: Max number of DL PDSCH layers for MU-MIMO spatial multiplexing in a cell with high traffic.
Very difficult to pair 8 UEs for 16 PDSCH layers.
Yes sharing not there.
PDCCH resources not paired.
PRB multiplexing there.
We’ve done it, but required huge efforts.
For 16 PDSCH you need each 8 users stay a in single beam out of 8 beams.
Also need to be very close to gNB.
Sorry, didn’t understand.
I mean without MU-MIMO sharing not there.
With MU-MIMO PRB multiplexing there.
For PDCCH resources not sure sharing there or not.
Huawei has Mu-MIMO for PDCCH as well.
4 layers for PDCCH.
In 5G I mean.
Please give brief for PDCCH MU-MIMO.
How it works?
Algorithm and criteria.
I am also struggling to understand how you can have 4 PDCCH layers with 16 PDSCH layers for 8 users, each one in a different beam…