Hi Experts.
In MU-MIMO, is it possible to get Rank 4?
One of my colleagues said that he got RI=4 during the testing with 2 UEs pairing.
In NR if UE is 4RX capable so with 4 SSB 2 UE in pairing.
As we know, RI reported by UE is the key parameter in deciding number of layers for Downlink.
Similar to this, what are the key parameters for deciding number of layers in UL MIMO?
4 SSB 2 UE means?
UL MIMO depends on UE capability whether it’s 2 TX or 4 TX.
4 SSB means 8 layers so per UE 4 layers so rank 4.
Okay. Why 4 SSBs are required to pair 2 UEs?
I didn’t understand 1 SSB = 2 layers.
Yes 1 SSB = 2 layers always.
Yeah, it is basic check.
Query was with respect to how eNodeB decides number of layers to be used in Uplink.
Mean any measurements taken by eNodeB for deciding number of layers in UL.
In my understanding there is no check we can configure Ul TM mode only.
Other can comment.
Doesn’t radio conditions in UL favorable for using UL MIMO?
In R16 MU-MIMO, each UE can reach 4 layers.
Does you get any improvement in Throughput?
And what impact seen in utilization?
I never seen phones supporting UL-MIMO, just seen Huawei tested with CPE.
Okay, thanks. I thought it is 2 as maximum.
I think firstly eNB has to check UE buffer status report.
eNB will prefer scheduling more RB than more layers.
If RB is full, then + layers.
R15, it is 2.
Yes, very good improvement in Rank 4 percentage.
Improvement compared with what?
How much? And throughput?
Can’t remember exactly.
Rank 4 percentage as compared to SU-MIMO.
But as of now they are doing stationary testing.
That feature supposed to only enhanced capacity, but practically negligible gain in OSS KPIs
Yes may be field throughput may be improved.