An information transmission method and apparatus. In the method, a terminal device generates a first codeword, where the first codeword is obtained based on a second codeword, a quantity of elements included in the second codeword is greater than a quantity of elements included in the first codeword, the second codeword is associated with a first coefficient set of a downlink channel, and the first coefficient set includes an element included in at least one row vector or column vector of a first coefficient matrix; and then the terminal device feeds back the first codeword to a network device. The terminal device can indicate a position and a numerical value of an element in the first coefficient set by reporting only the first codeword. This manner is simple. In addition, a codeword length of the first codeword is shorter than a codeword length of the second codeword.

A receiving device for use in a wireless OFDM communication system comprises two or more receive antennas for receiving OFDM signals received over a channel from a transmission device having two or more transmit antennas and applying transmit beamforming, and circuitry configured to perform channel estimation to estimate the channel, generate transmit beamforming information based on the channel estimation, the transmit beamforming information comprising beamforming information per subcarrier or time domain tap, determine a reduced set of transmit beamforming information from the transmit beamforming information, wherein the reduced set comprises beamforming information for a reduced set of subcarriers in the frequency domain or for a reduced set of taps in the time domain, wherein the subcarriers of the reduced set or the taps of the reduced set are determined based on an error criterion, and feed back the reduced set of transmit beamforming information to the transmission device.

Some embodiments of this disclosure provide a method for determining an index of an orthogonal basis vector and a device. The method includes: receiving position information, where the position information is associated with an orthogonal basis vector; and determining at least one first index set based on the position information, where the first index set represents a set of column indices of a plurality of orthogonal basis vectors in an orthogonal basis matrix.

A codebook subset restriction configuration can be received (410) from a network entity. A set of reference signals can be received (420) from the network entity. A set of frequency domain coefficients can be defined (430). The set of frequency domain coefficients can be an element of a discrete Fourier transform-compression codebook. The set of frequency domain coefficients can be generated (440) based on at least the restriction of the function of the amplitude restriction ratio of each beam in the set of restricted beams. At least one channel state information report containing the set of frequency domain coefficients can be transmitted (450).

Apparatuses, methods, and systems are disclosed for Type-II port-selection codebook generation. One apparatus includes a processor and a transceiver that receives a set of CSI-RS. The processor identifies a set of CSI-RS ports based on the set of CSI-RS. The processor selects a subset of CSI-RS ports from the identified set of CSI-RS ports based on a free selection of the respective CSI-RS ports from the identified CSI-RS ports. The processor generates, based on the set of CSI-RSs, at least one amplitude coefficient indicator and at least one phase coefficient indicator for each selected CSI-RS port generates a CSI report comprising a Type-II port-selection codebook corresponding to the generated coefficients and the subset of CSI-RS ports.

Facilitating sparsity adaptive feedback in the delay doppler domain in advanced networks (e.g., 4G, 5G, 6G, and beyond) is provided herein. Operations of a method can comprise determining, by a first device comprising a processor, a channel covariance matrix in a time-frequency domain based on a channel estimation associated with reference signals received from a second device. The method also can comprise decomposing, by the first device, the channel covariance matrix into a group of component matrices. Further, the method can comprise transforming, by the first device, respective matrices of the group of component matrices into respective covariance matrices in a delay doppler domain. The method also can comprise determining, by the first device, channel state information feedback in the delay doppler domain.

Methods, systems, and devices for wireless communications are described. A station (STA) may receive a null data packet (NDP) on a plurality of subcarriers, and the STA may generate a channel state information (CSI) matrix for each subcarrier of the plurality of subcarriers. After generating a CSI matrix for a subcarrier, such as at least one subcarrier, the STA may scale each value in the CSI matrix using a power-of-two value to minimize complexity. Specifically, instead of scaling each value in the CSI matrix to a value between zero and one using divisions (for example, which may be computationally expensive), the STA may use shifting to scale each value in the CSI matrix. The STA may then quantize the scaled values in the CSI matrix for reporting, and the STA may transmit the quantized, scaled values in the CSI matrix in a CSI report.

An approach is described that includes receiving a CSI report, where the CSI report includes a channel quality indicator (CQI), a rank indicator (RI), and a precoding matrix indicator (PMI). The approach further includes constructing a precoding matrix based on a linear combination of a plurality of mutually orthogonal digital Fourier transformation (DFT) spatial beams, and determining a number of bits for the PMI of the precoding matrix. The approach also includes determining a space frequency matrix based, at least in part, on the number of bits for the PMI and the precoding matrix, and compressing the space frequency matrix. Finally, the approach includes determining a compressed PMI based, at least in part, on the space frequency matrix.

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.

Apparatus and methods are provided to for a user equipment (UE) to report channel state information (CSI) to a base station. The UE sends UE capability signaling to a base station to indicate support of a codebook for high speed scenarios. The UE processes configuration information from the base station for CSI reporting using the codebook. The configuration information indicates measurement resources for one or more downlink (DL) channel. The UE measures a channel response and interference using the measurement resources, generates CSI feedback using the codebook for at least one ray from the base station to the UE, and reports the CSI feedback to the base station.