This application provides a precoding matrix indicating and determining method and a communications apparatus. The method includes: generating, by a terminal device, first indication information, and sending the first indication information to a network device, where the first indication information indicates a spatial domain vector, a frequency domain vector, and a weighting coefficient that are used to construct a precoding matrix. When a value of a rank Z is greater than 2, Z transport layers include at least one first-type transport layer, and a maximum quantity M.sub.1 of frequency domain vectors reported for the first-type transport layer satisfies:

[00001]$M_1=.Math.p_1\times \frac{N_3}{R}.Math.,$

wherein p.sub.1 is a preconfigured coefficient for determining the maximum quantity of frequency domain vectors reported for the first-type transport layer, 1≥p.sub.1>0, R is a preconfigured value, N.sub.3 is a length of a frequency domain vector, Z>2, and R, N.sub.3, and Z are all positive integers.

In an exemplary embodiment, a network node can receive signals from user devices in a wireless communication network. The network node can combine the signals received at each receive antenna of the network node based on vectors from a pre-defined set of vectors. The network node can also process the combined signals to obtain an estimate of the signals.

A UE determines a PMI, by performing at least the following: determining an intermediate set of vectors from a FD codebook; forming a subset of the intermediate set of vectors; mapping the subset of vectors to a combinatorial indicator; and forming the PMI at least from the combinatorial indicator. The UE sends the PMI toward a wireless network. A base station receives the PMI from the UE. The PMI includes a combinatorial indicator that maps to a subset of vectors from the FD codebook. The base station determines, using at least the received PMI, information from at least the FD codebook to apply to data for transmission toward the UE.

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.

Certain aspects of the present disclosure provide techniques for determining channel state information (CSI) reference signal (CSI-RS) resources and ports occupation for finer precoding matrix indication (PMI) granularity.

A method is provided for managing a downlink transmission in a Multi User-Multiple Input Multiple Output (MU-MIMO) system. The MU-MIMO system includes a base station and a set of remote radio units connected to the base station. The method includes: obtaining large scale fading data related to a large scale fading over uplink transmission associated with a user equipment (UE); generating a UE-specific channel vector by using the large scale fading data; and scheduling a downlink transmission by using the UE-specific channel vector.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a wireless communication device may select a set of terminals of a Butler matrix to use for transmitting or receiving one or more communications via one or more streams associated with one or more beams; and transmit or receive, using hybrid beamforming, the one or more streams via a set of antenna elements coupled to the Butler matrix. Numerous other aspects are provided.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first wireless communication device may select a lens, of a set of candidate lenses, and a butler matrix, of a set of candidate butler matrixes, to communicate a signal with a second wireless communication device, wherein the lens is spaced, from the butler matrix, at a distance that is at least a far field length of the lens for a frequency associated with the signal. The first wireless communication device may communicate, with the second wireless communication device, the signal via a beam of the butler matrix and the lens. Numerous other aspects are provided.

A wireless communication method for a terminal, a terminal, and a wireless communication system receive one or more Channel State Information Reference Signals (CSI-RSs). Further, quantization of combination coefficients of the one or more CSI-RSs corresponding to one or more spatial beams Discrete Fourier Transform (DFT) basis vector amplitudes is performed.

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.