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.

Techniques of generating CSI reports include designating at least one of the reports as a reference and the other reports as dependent on the reference. For example, a dependent CSI report may have a differential value of a CSI quantity rather than a raw value of the CSI quantity. Because generally for parameters in a CSI report, the differential quantity has a smaller range of values than the raw values of the CSI quantity, a quantization of the differential value of the CSI quantity will have fewer bits than the raw value; for example, for L1-RSRP, the raw value has 7 bits while the differential value has 4 bits. In another example, a dependent value of a CSI quantity is a flag indicating that the CSI quantity value is located in a reference CSI report.

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may monitor a first control channel in a first frequency band. The UE may determine that a bandwidth capability of the UE supports communicating on the first frequency band and at least a second frequency band. The UE may perform a channel measurement procedure on the first frequency band and the second frequency band concurrently. The UE may transmit a channel feedback message including information associated with the channel measurement procedure.

Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) may transmit feedback to a base station indicating phase values for sub-bands in a bandwidth part (BWP). The base station may use the phase feedback to perform precoding on a set of beams. To support a reduced payload overhead for the feedback, the UE may implement differential phase feedback. For example, the UE may divide the BWP into a number of sub-band groups and may generate, for each sub-band group of each beam, a first set of bits indicating an absolute phase value for a first sub-band of the sub-band group. The UE may additionally generate a second set of bits indicating differential phase values for the other sub-bands of each sub-band group. The UE may report the first and second sets of bits for the beams to the base station for precoding.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a set of reference signals from a base station and may determine a first set of channel state parameters. The UE may determine one or more preprocessed decoder parameters based on a downlink channel decoder of the UE and may perform one or more signal processing operations to determine one or more adjustment values for the first set of channel state parameters. The UE may transmit an indication of a the one or more adjustment values to the base station. In some implementations, the UE may transmit an indication of the one or more preprocessed decoder parameters to the base station and the base station may perform the one or more signal processing operations to determine the one or more adjustment values.

A method comprises: configuring multiple reporting modes for multi-level based transmitter (TX) beam index reporting for a particular beam/antenna panel group from a plurality of beam/antenna groups, wherein the multiple reporting modes includes at least one of a full reporting mode configuration for the particular beam/antenna panel group, a full reporting mode configuration common for the plurality of beam/antenna panel groups, a differential reporting mode, and a partial reporting mode, selecting a reporting mode from the multiple reporting modes, and sending a report based on the selected reporting mode.

A method for predicting channel state information is described. The method includes determining whether or not geodesic prediction is to be performed and transmitting the determination of whether or not geodesic prediction is to be performed in a first part of uplink control signaling. In response to determining that geodesic prediction is not to be performed, the method includes transmitting a current channel estimate in a second part of uplink control signaling, and in response to determining that geodesic prediction is to be performed, the method includes transmitting either a determined current value of a tangent vector, or a determined step size parameter, or both the determined current value of the tangent vector and the determined step size parameter in the second part of uplink control signaling. Channel state information is predicted based on information provided in the first and second parts of uplink control signaling.

Example channel information determining methods and apparatus are provided. One example method includes: after determining first channel information between a terminal device and a network device based on a downlink reference signal from the network device, the terminal device may determine feedback information based on the first channel information, and send the feedback information to the network device. The feedback information includes difference information between second channel information and third channel information, the second channel information is channel information that is in the first channel information and that corresponds to P antennas in M antennas of the terminal device, and the third channel information is channel information that is in the first channel information and that corresponds to M-P antennas in the M antennas.

A method for channel smoothing with transmit beamforming includes transmitting, by a first device, a non-data-packet (NDP) frame to a second device. The method also includes receiving, by the second device, the NDP frame and transmitting a compressed report to the first device. The method further includes receiving, by the first device, the compressed report and deriving a first beamforming matrix from the compressed report. A second beamforming matrix is generated employing a processing known to the second device, and a data frame is transmitted to the second device using the second beamforming matrix.

The generation of a channel state information report is provided. The generation includes transmitting reference signals to a user equipment, and receiving a reported set of quantized weighting coefficients, each of the weighting coefficients corresponding to a respective beam index and a respective tap index, where a set of beams based on the received reference signals is selected, where each of the beams corresponds to a discrete Fourier transform vector, and where each of the beams has a corresponding beam index. The tap index corresponds to a member of a Fourier basis set, where at least two subsets of the reported set of weighting coefficients are quantized according to separate quantization procedures.