Ul mu mimo

Hello experts,
I understand the concept of DL MU MIMO in the sense that a number of users are served in the same time and frequency resources but they are separated in the spatial domain by precoding at the base station.

However what does it mean to have UL MU-MIMO? Since the users are distributed and precoding is at different UE I am not sure what is meant by UL MU MIMO. Does it mean we allow users to transmit in same subband? And does 5G NR support UL MU MIMO?
Thank you

Any help appreciated

Yes, 5G NR supports MU-MIMO. Huawei for example can have 8 PUSCH layers in uplink for MU-MIMO and 16 pdsch layers in DL. Simultaenous for paired users.

For DL MU-MIMO my understanding is that they are not “separated in the spatial domain by precoding at the base station” like you mentioned. Simply put: each user is served by a different PDSCH beam that does not interfere too much with other MU-MIMO UEs that are paired together.

@RFSpecialist thank you very much! How does gnb choose UE in UL MU MIMO? How does it make sure they are orthiginal?