Abstract: Embodiments of this application disclose a channel estimation method and apparatus, and relate to the field of communications technologies. One example method include: generating and sending indication information, where the indication information is used to indicate L space-frequency basis vectors for constructing an M×N-dimensional space-frequency vector; the space-frequency vector includes M N-dimensional precoding vectors, each precoding vector is used in one of M frequency bands, and the space-frequency vector is generated by performing a weighted combination on L space-frequency component vectors; each of the L space-frequency component vectors is a vector including M×N elements that are in one of the L space-frequency basis vectors, and each of the L space-frequency basis vectors is an Nf×N-dimensional vector; the space-frequency basis vector is a three-dimensional oversampled (DFT) vector; and L?2, Nf?M?1, N?2, and L, M, N, and Nf are all integers.

Abstract: This application provides an information transmission method, an apparatus, and a device, which are applicable to the communication field, and are used to feed back information obtained based on channel information of different network devices, so as to improve performance gains and reduce performance loss.

Abstract: This application provides a communication method. In an embodiment a communication method includes receiving first downlink control information (DCI) from a network device, wherein the first DCI is for activating a training process, and wherein the training process is for training a model corresponding to target information.

Abstract: A channel measurement method and a communication apparatus are provided. The method includes: generating channel information, where the channel information indicates one or more receive beam vectors and one or more weighting coefficients, each of the one or more weighting coefficients corresponds to one receive beam vector, the one or more receive beam vectors and the one or more weighting coefficients corresponding to the one or more receive beam vectors are used to determine a channel of at least one frequency domain unit between a terminal device and a network device, the one or more receive beam vectors are selected from a receive beam vector set, and the receive beam vector set is determined based on a predefined base vector set; and sending the channel information.

Abstract: This disclosure discloses an information indication method and an apparatus, to resolve a problem that indication precision of an uplink precoding matrix is low. The method includes: receiving a downlink reference signal sent by a network device on a first transmission resource; performing channel estimation based on the downlink reference signal, to obtain a downlink equivalent channel corresponding to the first transmission resource; and determining, based on the downlink equivalent channel, to-be-indicated information corresponding to a terminal device, where the to-be-indicated information indicates an uplink precoding matrix used when a first terminal device sends uplink data on the first transmission resource. The downlink equivalent channel is obtained by performing channel estimation based on the downlink reference signal.

Abstract: This application discloses a method for sending a demodulation reference signal, a method for receiving a demodulation reference signal, and a communication apparatus. The method for sending a demodulation reference signal includes: A network device generates a first signal and sends the first signal on a first time-frequency resource, where the first signal is formed by superimposing M DMRS port signals, and delay segmentation locations corresponding to at least two of the M DMRS port signals are different. Because the first signal is formed by superposing the M DMRS port signals, that is, the network device sends a plurality of DMRS port signals on a same time-frequency resource, reference signal overheads can be reduced. The network device sends more DMRS port signals on the same time-frequency resource. In this way, the network device can send more streams without increasing pilot overheads.

Abstract: Example channel measurement methods and communications apparatus are described. One example method includes receiving a precoded reference signal by a terminal device, where the precoded reference signal is obtained by precoding a reference signal based on K angle vectors and L delay vectors. First indication information is generated and sent, where the first indication information is used to indicate P weighting coefficients corresponding to P angle-delay pairs. The P weighting coefficients are determined by using the precoded reference signal. The P angle-delay pairs and the P weighting coefficients corresponding to the P angle-delay pairs are used to determine a precoding matrix. Each angle-delay pair includes one of the K angle vectors and one of the L delay vectors. The K angle vectors and the L delay vectors are determined based on uplink channel measurement.

Abstract: This application provides a data transmission method, so that data transmission reliability can be improved. The method includes: receiving, by the terminal device, a plurality of reference signals used for channel measurement; and sending, by the terminal device, a plurality of pieces of first indication information based on the at least one reference signal and a transmission scheme on which CSI feedback is based, where the plurality of pieces of first indication information are used to indicate x target precoding matrices, at least one of the plurality of pieces of first indication information is used to indicate one target precoding matrix, and the x target precoding matrices are determined based on the plurality of precoding matrices, where x is a quantity of target precoding matrices that need to be fed back, and x is an integer greater than 1.

Abstract: This disclosure provides methods and apparatuses for generating precoding vectors. One method includes: receiving a channel state information (CSI) report, wherein the CSI report indicates a quantity of space-frequency vector pairs to be reported for a quantity of R transport layers, wherein a size of an overhead for indicating the quantity of the space-frequency vector pairs is same when the quantity of R is greater than or equal to 2, wherein each of the space-frequency vector pairs comprises one spatial domain vector and one frequency domain vector, and wherein for each of the R transport layers, one or more frequency domain units associated with the transport layer correspond to one or more precoding vectors, and determining the quantity of space-frequency vector pairs according to the CSI report.

Abstract: Embodiments of this application provide a channel estimation method and apparatus, and relate to the field of communications technologies, to help reduce indication overheads. The method includes: generating and sending indication information, where the indication information is used to indicate M N-dimensional precoding vectors, each precoding vector is applied to one of M frequency bands, the M N-dimensional precoding vectors form a space-frequency matrix, and the space-frequency matrix is generated by performing weighted combination on a plurality of space-frequency component matrices, where the space-frequency matrix is an M×N-dimensional space-frequency vector or an X×Y space-frequency matrix, X and Y are one and the other of M and N, M?1, N?2, and both M and N are integers.

Abstract: A channel measurement method and a communications apparatus. The method includes: a terminal device receives precoded reference signals from a network device, where the precoded reference signals are obtained by precoding reference signals based on K angle vectors; and generates and sends first indication information, where the first indication information is used to indicate P weighting coefficients corresponding to P angle-delay pairs, the P weighting coefficients are determined based on the precoded reference signals, each of the P angle-delay pairs includes one angle vector and one delay vector corresponding to the angle vector, a delay vector corresponding to each angle vector is preconfigured, each angle vector and the delay vector corresponding to each angle vector are obtained through uplink channel measurement, and the P angle-delay pairs and the P weighting coefficients corresponding to the P angle-delay pairs are used to determine a precoding matrix.

Abstract: The application provides a beam training method and a communications apparatus. The method includes: generating, by a terminal device, capability indication information, where the capability indication information is used to indicate that the terminal device can support simultaneous beam training in a maximum of N frequency bands, and N is an integer greater than or equal to 1; and sending, by the terminal device, the capability indication information. In this way, the network device may select a plurality of frequency bands at a time based on a capability of the terminal device to simultaneously perform beam training. Therefore, in an embodiments of this application, when the quantity N, of frequency bands for simultaneous training, supported by the terminal device is greater than 1, beam training may be simultaneously performed between the network device and the terminal device in a plurality of frequency bands.

Abstract: This application discloses a channel estimation method and apparatus, and relates to the field of communications technologies, to help reduce indication overheads. The method may include: generating and sending indication information. The indication information is used to indicate K N-dimensional spatial-domain component vectors, L M-dimensional frequency-domain component vectors, and a weight matrix, to indicate to construct an M×N-dimensional spatial-frequency matrix, or an M×N or N×M spatial-frequency matrix.

Abstract: Embodiments of this application provide a measurement reporting method and apparatus, to improve poor data transmission performance caused by inaccurate channel state information feedback. The method includes: performing channel measurement based on a downlink reference signal from a network device, and reporting a measurement result to the network device. The measurement result indicates T resource elements and a superposition coefficient, and the resource element is determined based on at least one of the following base vectors: a time domain base vector and a receive side spatial domain base vector, and T is an integer greater than 0. In embodiments of this application, a channel feature of a channel in an angle domain can be more accurately indicated by using the receive side spatial domain base vector, and a time variant feature of the channel can be reflected by using the time domain base vector.

Abstract: Example channel measurement methods and communications apparatus are described. One example method includes receiving a precoded reference signal by a terminal device, where the precoded reference signal is obtained by precoding a reference signal based on K angle vectors and L delay vectors. First indication information is generated and sent, where the first indication information indicates P weighting coefficients corresponding to P angle-delay pairs. The P weighting coefficients are determined by using the precoded reference signal. The P angle-delay pairs and the P weighting coefficients corresponding to the P angle-delay pairs are used to determine a precoding matrix. Each angle-delay pair includes one of the K angle vectors and one of the L delay vectors. The K angle vectors and the L delay vectors are determined based on uplink channel measurement.

Abstract: A channel measurement method and a communications apparatus. The method includes: a terminal device receives precoded reference signals from a network device, where the precoded reference signals are obtained by precoding reference signals based on K angle vectors; and generates and sends first indication information, where the first indication information is used to indicate P weighting coefficients corresponding to P angle-delay pairs, the P weighting coefficients are determined based on the precoded reference signals, each of the P angle-delay pairs includes one angle vector and one delay vector corresponding to the angle vector, a delay vector corresponding to each angle vector is preconfigured, each angle vector and the delay vector corresponding to each angle vector are obtained through uplink channel measurement, and the P angle-delay pairs and the P weighting coefficients corresponding to the P angle-delay pairs are used to determine a precoding matrix.

Abstract: This application provides a methods and apparatuses for generating precoding vectors. One method comprises: generating a channel state information (CSI) report, wherein the CSI report indicates a quantity of space-frequency vector pairs to be reported for each of a quantity of R transport layers, wherein a size of an overhead for indicating the quantity of the space-frequency vector pairs is unrelated to the quantity of R, wherein each of the space-frequency vector pairs comprises one spatial domain vector and one frequency domain vector, wherein for each of the R transport layers, one or more frequency domain units associated with the transport layer correspond to one or more precoding vectors, and wherein each of the one or more precoding vectors is constructed by one or more space-frequency vector pairs to be reported for the corresponding transport layer in the R transport layers; and transmitting the CSI report.

Abstract: Embodiments of this application disclose terminal device capability transmission methods, apparatuses, and systems. In an implementation, a terminal device transmits capability information to a network device, the capability information indicates a maximum quantity of ports of reference signals for channel state information (CSI) measurement supported by a terminal device in a time-domain unit, wherein the time-domain unit is one slot, and the capability information is determined based on a capability of the terminal device.

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.