How gNB indicate the MU-MIMO Codebook to UE?

Specs & Protocol Testing
1

Hi Experts.

Does anyone know how gNB indicate the MU-MIMO Codebook to UE?

Is that in DCI?

2

DCI0_1 TMPI field

In gNB’s perspective, a typical way is to tell UE to send SRS and pick a specific PMI based the channel estimation of SRS, and tell UE via DCI 0_1 (TMPI field) to use a specific PMI.

In this case, UE shall use the specific precoding matrix specified by gNB.

If we can assume that UE and gNB is in such a condition where channel reciprocity is guaranteed (like well calibrated TDD channel), gNB can use the channel information from SRS.

3

Thanks. Is that applicable to MU MIMO?

4

Yes, it is.

1 Like