*3.7.3 Procedure for CSI-RS based single user MIMO*


3.UE reports PMI, RI, CQI to gNB.

4. gNB decides a precoder to transmit PDSCH.

#### **3.8 Multi-user MIMO schemes**

In Multi User MIMO schemes, gNB tries to communicate simultaneously with a set of UE through the same time/frequency resources. MU-MIMO schemes uses Type II codebook to provide more details about Channel State Information. MU-MIMO schemes support to a maximum of 2 layers per UE. This is smaller than that of SU-MIMO (up to 8 layers for type I single panel) but the maximum number of layers per cell is higher to allow multiple UE to use 2 2 MIMO simultaneously.

DL MU-MO Type II codebook allocates a set of beams to each UE. Each set of the beam is the weighted combination of beams with relative amplitudes and cophasing phase shifts.

Beamformed CSI-RS relies upon the gNB having some advanced information to allow beamforming of the CSI Reference Signal transmissions.

Procedure for beamformed CSI-RS as follows: gNB transmits one or more CSI-RS, each in different "directions". UE computes and reports CRI/PMI/CQI to gNB.

### *Multiplexing Techniques for Applications Based-on 5G Systems DOI: http://dx.doi.org/10.5772/intechopen.101780*


**Table 6.**

*Single panel antenna configuration.*


**Table 7.**

*Multi panel antenna configuration.*
