PUCCH PDSCH-CodeBlockGroupTransmission = OFF Type-2 HARQ-ACK codebook in PUSCH 4.1.9 Downlink MIMO Schemes The new radio downlink control and traffic channels rely on DM-RSs to facilitate coherent detection where a UE can assume that the DM-RSs are jointly precoded with the data. In NR Rel-15, downlink multi-antenna precoding is transparent to the UE and the network can apply any transmitter-side precoding without informing the device about the selected preco- der. The specification impact of downlink multi-antenna precoding is therefore mainly related to the measurements and reporting mechanisms conducted by the device to support network selection of precoder for downlink transmissions. These precoder-related measure- ments and reporting are part of the more general CSI reporting framework based on report configurations which was described in previous sections. A CSI report may consist of rank indicator (RI), precoder-matrix indicator (PMI), and CQI indicating a suitable transmission rank, precoding matrix given the selected rank, coding and modulation scheme given the selected precoder matrix, respectively, from the device perspective. As we mentioned earlier, the reported PMI is a suitable precoder matrix from the UE perspective to be used for downlink transmissions. Each PMI value corresponds to a specific precoder matrix or codebook. Note that the device selects PMI based on a certain number of antenna ports, given by the number of antenna ports of the configured CSI-RS associated with the report configuration, and the selected rank. There is at least one code- book for each valid combination of antenna ports and rank. It must be understood that the suggested codebooks by the UE do not compel the gNB, in practice, not to use another pre- coding matrix for downlink transmission to the device. The MU-MIMO schemes typically require detailed knowledge of the channel experienced by each device at the gNB compared to SU-MIMO precoding and transmission to a single device. Therefore, NR defines two types of CSI that