Abstract: A channel state information feedback method includes: a terminal receives first indication information from a network device, and the terminal sends channel state information to the network device. The first indication information is used to indicate a type of a right multiplication matrix in a first codebook, and the first codebook satisfies a formula (I). W is the first codebook, W1 is a port selection matrix, (II) is a linear superposition coefficient matrix, Wf is the right multiplication matrix, and (III) is a conjugate transpose of Wf, and is used by the terminal to determine the channel state information based on the first codebook. According to the method, when there are a plurality of codebooks, the codebook used by the terminal to obtain the CSI can be clearly indicated.

Abstract: This application describes a channel information feedback method and a communication apparatus. The method includes a terminal device that receives configuration information sent by a network device, where the configuration information is used to configure a feedback mode of channel information. The terminal device may feed back current channel information to the network device when the feedback mode configured by using the configuration information is a first mode. The terminal device may alternatively feeds back predicted channel information to the network device when the feedback mode configured by using the configuration information is a second mode. System performance is therefore improved by the method described in this application because channel information feedback requirements in different scenarios can be met.

Abstract: In accordance with an embodiment, a method includes obtaining Mv frequency domain components, where the Mv frequency domain components are a subset of N candidate frequency domain components, and Mv is a positive integer; and sending first indication information, where the first indication information indicates the Mv frequency domain components, the first indication information occupies ? log 2 ? ( N - 1 M v - 1 ) ? bits, and N is a positive integer greater than Mv.

Abstract: This application provides a communication method and an apparatus. A terminal device receives a first indication information from a network device, where the first indication information indicates a first parameter combination including at least two of the following: a first value of Mv, a first value of ?, and a first value of ?. The first parameter combination is for determining that a first coefficient matrix to be indicated by the terminal device includes a maximum of K0 non-zero elements, and K0 is determined based on the first values of Mv, ?, and ?. The terminal device sends a second information indication to the network device, where the second indication information indicates K2 non-zero elements in the first coefficient matrix, and K2 is less than or equal to K0.

Abstract: Embodiments of this application disclose an information feedback method and a related apparatus. A terminal device sends first information to a network apparatus, where the first information includes a total quantity of nonzero coefficients at all spatial layers of the terminal device, and the nonzero coefficients are used to constitute a weighting coefficient matrix in a codebook. The first information further includes first indication information, and the first indication information indicates whether second information sent by the terminal device to the network apparatus carries indication information of a location of a nonzero coefficient. In this way, a coding bit rate of the indication information sent by the terminal device to the network apparatus is reduced while correct data transmission is ensured.

Abstract: Embodiments of this application provides a channel information feedback method and a communication apparatus. In the method, first information and a strongest coefficient indicator (SCI) have a same priority in uplink control information (UCI) sent by a terminal device. The first information indicates a second frequency domain discrete Fourier transform (DFT) vector set selected by the terminal device, and the SCI indicates a space-frequency vector corresponding to a strongest coefficient in a first space-frequency vector set corresponding to the second frequency domain DFT vector set and channel state information reference signal (CSI-RS) ports selected by the terminal device. In other words, the SCI indicates the space-frequency vector that corresponds to the second frequency domain DFT vector set selected by the terminal device and that corresponds to the strongest coefficient.

Abstract: This application relates to the field of communication technologies, and provides an information transmission method and an apparatus. In this method, a radio access network device sends, to a terminal device, first indication information indicating first information and second information and second indication information indicating a first quantity of DFT vectors, the first information indicates a first quantity of to-be-selected ports, and the second information indicates a first compression factor. The radio access network device further sends a reference signal to the terminal device. The terminal device sends downlink channel state information to the radio access network device based on the first indication information, the second indication information, and the reference signal. The compression factor is a compression factor of a complex coefficient matrix. There is a correspondence between the compression factor and a quantity of transport layers.

Abstract: This application provides a channel information obtaining method and a related device. In the method, first indication information may be received, where the first indication information indicates one of a plurality of parameter configuration combinations of a reference signal, and the plurality of parameter configuration combinations are associated with a same codebook. A terminal device may feed back channel state information based on the indicated parameter configuration combination.

Abstract: Embodiments of this application provide an update method and a communications apparatus. The method includes: generating space domain vector update information, where the space domain vector update information is for updating a first group of space domain vectors to obtain a second group of space domain vectors, the space domain vector update information includes a plurality of groups of space domain vector coefficients, and each group of space domain vector coefficients is for performing weighted combination on the first group of space domain vectors, to obtain one space domain vector in the second group of space domain vectors; and sending the space domain vector update information.

Abstract: A method for indicating channel state information CSI measurement and a communication apparatus. A network device indicates, to a terminal device by using first indication information, one or more frequency domain units in a downlink reference signal resource that are used by the terminal device to obtain CSI. The terminal device determines, based on the first indication information, which frequency domain units in the downlink reference signal resource are used to obtain the CSI, and perform measurement in the frequency domain unit to obtain the CSI. The network device flexibly configures CSI measurement based on a system status, to control obtaining of the CSI. This helps the terminal device obtain the CSI more pertinently based on the indication in different cases.

Abstract: A channel state information feedback method includes: a terminal receives first indication information from a network device, and the terminal sends channel state information to the network device. The first indication information is used to indicate a type of a right multiplication matrix in a first codebook, and the first codebook satisfies a formula (I). W is the first codebook, W1 is a port selection matrix, (II) is a linear superposition coefficient matrix, Wf is the right multiplication matrix, and (III) is a conjugate transpose of Wf, and is used by the terminal to determine the channel state information based on the first codebook. According to the method, when there are a plurality of codebooks, the codebook used by the terminal to obtain the CSI can be clearly indicated.

Abstract: This application describes a channel information feedback method and a communication apparatus. The method includes a terminal device that receives configuration information sent by a network device, where the configuration information is used to configure a feedback mode of channel information. The terminal device may feed back current channel information to the network device when the feedback mode configured by using the configuration information is a first mode. The terminal device may alternatively feeds back predicted channel information to the network device when the feedback mode configured by using the configuration information is a second mode. System performance is therefore improved by the method described in this application because channel information feedback requirements in different scenarios can be met.