A transceiver can transmit a codebook subset restriction configuration including a set of restricted beams. A channel state information report including a plurality of sets of quantized coefficients based on the codebook subset restriction configuration can be received. A set of quantized weights can be based on a least a Fourier transform of a set of quantized coefficients of the particular restricted beam. The plurality of sets of quantized coefficients can be based on quantized weights of the particular restricted beam satisfying a constraint. The plurality of sets of quantized coefficients can be further based on a set of coefficients quantized to determine the plurality of sets of quantized coefficients. The set of coefficients can be generated by transforming a set of beam weights from a frequency domain to a time domain, where the beam weights correspond to a transmitted beam.

A method for operating a UE for CSI reporting is provided. The method comprises receiving configuration information for a CSI report, determining the CSI report comprising a first CSI part and a second CSI part, the second CSI part including a precoding matrix indicator (PMI), the PMI comprising a plurality of PMI components, wherein some of the PMI components comprise sub-components, determining priority values for the sub-components of the some of the PMI components, partitioning the second CSI part into Group 0, Group 1, and Group 2 such that the sub-components of the some of the PMI components are divided into Group 1 and Group 2 based on the determined priority values for the sub-components, and transmitting the first CSI part and Group 0 or (Group 0, Group 1) or (Group 0, Group 1, Group 2) of the second CSI part based on a resource allocation for the CSI report.

A method performed by a wireless device (510, 800, 1200) for reporting channel state information (CSI) for a downlink channel is disclosed. The method comprises transmitting (601, 705) a CSI report for the downlink channel to a network node (560, 1100), the CSI report comprising: a set of reported coefficients; an indication of how the network node is to interpret the set of reported coefficients; and an indication of a payload size of the set of the reported coefficients.

Systems and methods for wireless communications are disclosed herein. A first communication node reports at least one codeword, a number of antenna ports, a coherence capability of the antenna ports, or a full power transmission mode for the at least one uplink transmission to a second communication node. The at least one codeword is determined based on the number of antenna ports, the coherence capability, and the full power transmission mode. The at least one codeword includes at least one precoding matrix group or at least one Transmission Precoding Matrix Index (TPMI) group corresponding to the at least one precoding matrix group.

Apparatuses, methods, and systems are disclosed for preparing channel state information (“CSI”). One apparatus includes a processor and a transceiver configured to communicate with a base unit over a radio access network using at least one transmission layer and determining a total number of non-zero coefficients over a set of layers. The processor encodes the total number of non-zero coefficients by selecting a codeword from a plurality of candidate codewords in which the selected single codeword identifies the total number of non-zero coefficients to the base unit. The processor prepares CSI, where the CSI comprises the selected single codeword encoding the total number of non-zero coefficients and the transceiver transmits the CSI to the base unit.

The embodiments herein relate to a method performed by a UE (900) for providing a channel state information (CSI) feedback in a wireless communication system including at least the UE and a gNB (800) or a radio network node. The UE (900) is operative, by means of e.g. the processor (910) to: estimate the MIMO channel between the gNB (800) and the UE (910) based on received DL reference signals for the configured resource blocks. The UE (900) is further operative to calculate, based on a performance metric, a precoder matrix, for a number of antenna ports of the gNB (800) and configured subbands, the precoder matrix being based on two codebooks and a set of combination coefficients for complex scaling/combining one or more of vectors selected from a first codebook and a second codebook, and the UE (900) is operative to report a CSI feedback and/or a PMI and/or a PMI/RI, to the gNB (800), used to indicate the precoder matrix for the configured antenna ports and resource blocks.

Method and UE are provided for determining precoder of MIMO system. In particular, a BS can transmit at least one CSI-RS to the UE. The UE can receive the at least one CSI-RS, and estimate at least one covariance matrix of at least one downlink channel matrix according to the at least one CSI-RS at different times and frequencies. Then, the UE can transmit the at least one covariance matrix or at least one parameter associated with the least one covariance matrix to the BS for the BS to reconstruct at least one covariance matrix, and determine a precoder according to the at least one reconstructed covariance matrix.

Certain aspects of the present disclosure provide techniques for reducing overhead for channel state information (CSI). Certain aspects provide a method for wireless communication. The method generally includes receiving a channel state information reference signal (CSI-RS), determining one or more feedback components associated with a CSI feedback type based on the CSI-RS, identifying that a payload of the one or more feedback components is to be compressed, compressing the payload, and reporting the compressed payload.

A wireless communication system non-collaborative, multiple input, multiple output (MIMO) space division multiple access (SDMA) system determines subscriber station combining and weighting vectors that yield a high average signal-to-interference plus noise ratio (SINR). Each subscriber station independently transmits information to a base station that allows the base station to determine a weight vector w.sub.i for each subscriber station using the determined combining vector of the subscriber station. The i.sup.th combining vector corresponds to a right singular vector corresponding to a maximum singular value of a channel matrix between a base station and the i.sup.th subscriber station. Each subscriber station transmits signals using a weight vector v.sub.i, which corresponds to a left singular vector corresponding to a maximum singular value of a channel matrix between the i.sup.th subscriber station and the base station. The base station uses the weight vector w.sub.i to determine the signal transmitted by the i.sup.th subscriber station.

A CBSR configuration can include a set of restricted beams. Each restricted beam can be constrained by a configured maximum allowed gain value. A set of beams including one or more restricted beams can be selected. A set of precoder coefficients can be determined for each selected beam. A function of the set of precoder coefficients can satisfy the configured maximum allowed gain value. The function can be proportional to a square root of an average of squared values of amplitudes of members of the subset. A CSI report can be transmitted. The CSI report can include at least an indicator of the set of selected beams and an indicator of the set of precoder coefficients corresponding to each selected beam.