If one UE in a cell use SRS-based BF and another UE uses CSI-RS based BF, they can be paired MU-MIMO or not?
In my view for MU-MIMO only srs based used as without SRS u can’t calculate AoA needed for MU-MIMO algorithm.
If 2 UEs using CSI-RS based BF, gNB can know they are in different CSI-RS beams, space isolation is ok, they can be paired also.
Beams are different for srs bf and csi-rs bf so in my opinion answer is NO.
Ok, you mean refined beam used by users i.e. 1 ssb = 4 CSI-RS beams.
At that level MU-MIMO I don’t think will work.
Users should be spatialy separated for MU-MIMO.
This separation can be judged by looking at csi rs measurement from both UEs or srs masurements.
One UEs csi rs and others srs measurement may not be enough for judging separation.
Normally, BF based on SRS is for near UE, based on CSI is for far UE.
This is Huawei algo and is based on parameters that can be changed anytime.
Yes, it is parameter setting.
But if they can set to differentiate CCU and CEU, so they can pair UEs in different locations.
For example Huawei uses now srs bf till ul sinr of srs is -15 dB.
How AoA calculated from csi rs measurements? I mean user vertical and horizontal angle?
MIMO, gnb no need to calculate AoA.
Positioning service need calculate AoA.
I think SRS based BF is for open-loop implicit BF based on TDD propagation channel reciprocal property, CSI-RS based BF closed loop BF based on PMI/rank feedback. Based station should be handle both if they use more advanced BF algorithm.
just be a BF applicable to the whole band. But for near UE, wide-band (subcarrier based) shall be used for BF. In this sense, it is difficult to pair them together as MU-MIMO user group to get optimal inter-user interference.