A method, system and apparatus for beamforming techniques that use approximate channel decomposition are disclosed. According to one aspect, a wireless device is provided. The wireless device includes processing circuitry configured to use a non-constant modulus, NCM, precoder of a NCM codebook to transmit on a physical channel where the NCM codebook is based at least in part on a constant modulus, CM, codebook and a plurality of NCM component matrices, and where the plurality of NCM component matrices are based at least in part on a NCM component matrix mathematical expression, and where an approximate decomposition element-wise product of a CM component matrix mathematical expression and the NCM component matrix mathematical expression corresponds to a channel decomposition matrix.

A method for operating a user equipment (UE) comprises receiving information about a channel state information (CSI) report, the information including information about two parameters for basis vectors, N and M; determining n.sub.3.sup.(0) . . . n.sub.3.sup.(M-1), wherein n.sub.3.sup.(0) . . . n.sub.3.sup.(M-1) are indices of M basis vectors selected from N basis vectors; determining nonzero offsets between the index n.sub.3.sup.(0) and indices n.sub.3.sup.(1) . . . n.sub.3.sup.(M-1); and transmitting the CSI report including an indicator i.sub.1,6 indicating the nonzero offsets between n.sub.3.sup.(0)and the indices n.sub.3.sup.(1) . . . n.sub.3.sup.(M-1).

Enhanced channel state information (CSI) feedback is disclosed for full dimensional multiple input, multiple output (FD-MIMO) operations. In one aspect, a single CSI process is defined that is configured with an azimuth and elevation CSI-reference signal (RS) ports. A user equipment (UE) will send a precoding matrix indictor (PMI) report including a precoding matrix indicator (PMI) for the azimuth ports and a PMI for the elevation ports. One of the PMIs is assigned a low rank. The base station will use the two PMIs to create a whole channel precoding matrix. In another aspect, a single CSI process is configured having a plurality of CSI-RS resources. The UE generates channel measurement information for each of the CSI-RS resources, but only sets a CSI report to the base station of a subset of the total number of resources.

The present disclosure relates to a method, performed by a user equipment (UE), for reporting channel state information (CSI) in a wireless communication system and an apparatus therefor. According to the present disclosure, the UE receives a channel state information reference signal (CSI-RS) from a base station through a multiple antenna port; and reports the CSI to the base station, wherein the CSI includes a precoding matrix indicator for a codebook generated by linear combination, wherein the codebook is generated based on a specific parameter set, and wherein the specific parameter set is differently set/applied based on at least one of a rank value or at least one layer index of a specific rank.

The present disclosure provides a method of generating codebook in a wireless communication system with multiple antenna arrays, as well as a wireless communication system, base station and terminal using the codebook for communication. The method comprises steps of: providing a basic codebook which contains multiple pre-coding matrices; and assigning phase offsets to certain pre-coding matrices in the basic codebook to form a codebook with phase offset. The feedback overhead from a client to a base station side is reduced and a good precision of feedback for multi-antenna array is kept by applying the method of generating codebook and using the generated codebook in the wireless communication system, base station and terminal.

A method for a channel state information (CSI) feedback comprises receiving CSI feedback configuration information for the CSI feedback including a spatial channel information indicator based on a linear combination (LC) codebook, wherein the spatial channel information comprises at least one of a downlink channel matrix, a covariance matrix of the downlink channel matrix, or at least one eigenvector of the covariance matrix of the downlink channel matrix; deriving the spatial channel information indicator using the LC codebook that indicates a weighted linear combination of a plurality of basis vectors or a plurality of basis matrices as a representation of at least one of a downlink channel matrix, a covariance matrix of the downlink channel matrix, or at least one eigenvector of the covariance matrix of the downlink channel matrix; and transmitting over an uplink channel, the CSI feedback including the spatial channel information indicator.

Disclosed are methods and apparatuses for performing precoding. A method disclosed comprises steps of: transmitting a CSI reference signal to a UE to request the UE to report status-related information of respective panels; acquiring, based on first feedback information from the UE, the status-related information of the respective panels whose status-related information has been measured by the UE and a serving panel selected by the UE; and performing, based on the status-related information of the respective panels and the serving panel selected by the UE, two-stage beamforming separately to the respective panels, so as to first perform decoupling to suppress inter-panel interference and then perform per-panel precoding. The disclosure offers the following advantages: effectively eliminating the inter-panel and intra-panel interference, avoiding complex inter-panel calibration, and reducing implementation complexity and CSI feedback overhead.

An apparatus for mapping data in a wireless communication system. The apparatus includes circuitry for generating a precoding matrix for multi-antenna transmission based on a precoding matrix indicator (PMI) feedback from at least one remote receiver where the PMI indicates a choice of precoding matrix derived from a matrix multiplication of two matrices from a first code book and a second codebook. The apparatus further includes circuitry for precoding one or more layers of a data stream with the precoding matrix and transmitting the precoded layers of data stream to the remove receiver.

A method for operating a user equipment (UE) comprises receiving channel state information (CSI) reporting configuration information including a CSI reporting band and a frequency granularity of CSI reporting, where the CSI reporting band is within a bandwidth part (BWP) comprising M physical resource blocks (PRBs), and the frequency granularity of CSI reporting is based on whether M<N, where N is a threshold; identifying the frequency granularity of CSI reporting; generating a CSI report with the identified frequency granularity, wherein the CSI report includes at least one of a precoding matrix indicator (PMI) and a channel quality indicator (CQI); and transmitting the CSI report over an uplink (UL) channel.

This application provides a channel measurement method and apparatus. The method includes: receiving measurement configuration information from a network device, and performing joint channel measurement based on the measurement configuration information, where the measurement configuration information is used to configure one or more groups of measurement resources, each group of measurement resources includes a plurality of measurement resources, and the group of measurement resources is used to perform joint channel measurement once.