Abstract: The disclosure provides channel measurement methods and communications apparatuses. One example method includes a terminal device that generates first indication information, and sends the first indication information to a network device. The first indication information indicates one or more component characteristics of a complete time-varying characteristic of a channel and a weighting coefficient of each component characteristic. The complete time-varying characteristic of the channel corresponds to a local time-varying characteristic of the channel. The local time-varying characteristic may be determined by the terminal device based on reference signals received for a plurality of times, and the complete time-varying characteristic may be determined based on the local time-varying characteristic.

Abstract: The present disclosure relates to precoding vector indicating and determining methods and communications apparatus. In one example method, a terminal device generates first indication information, and sends the first indication information to a network device. The first indication information is used to indicate one or more frequency domain vectors and one or more weighting coefficients, where the one or more frequency domain vectors include a frequency domain vector reported for each of R frequency domain unit groups, the one or more weighting coefficients include a weighting coefficient reported for each of the R frequency domain unit groups, and a frequency domain vector and a weighting coefficient that are reported for an rth frequency domain unit group in the R frequency domain unit groups are used to construct a precoding vector corresponding to one or more frequency domain units in the rth frequency domain unit group.

Abstract: A multilayered optical security device has a resonant waveguide grating (RWG) layer on an under layer having a hologram. The RWG layer has plural RWGs for generating one or more patterns. Each RWG has first and second RWG portions, with diffraction gratings of different grating periods, for light coupling-in and coupling-out, respectively. Using the RWGs minimizes interference to a holographic image generated by the under layer. This advantage is especially useful when the holographic image carries digital data such as in digital holographic encryption where an encrypted hologram is used in the under layer. The digital data may contain biometric information such as a fingerprint. In each RWG portion of an individual RWG, scattering elements in a grating are curved to thereby enhance an angular tolerance in azimuthal angle during observing the patterns by an observer while the individual RWG is still selective in elevation angle.

Abstract: This application provides example channel measurement methods and example communication apparatuses. One example method includes determining L weighting coefficients for determining channels of K moments based on channels of M moments, where L, M, and K are all positive integers. Information about the L weighting coefficients can then be sent.

Abstract: This application provides a method for indicating vectors used to construct a precoding vector and a communications apparatus. The method includes: generating a CSI report; and transmitting the CSI report to a network device. The CSI report is used to indicate a quantity of space-frequency vector pairs reported for R transport layers, and indication overheads of the quantity of space-frequency vector pairs are irrelevant to a quantity R of the transport layers. Through fixing of the indication overheads, the indication of the quantity of space-frequency vector pairs reported for the R transport layers may be designed in a first part of the CSI report, so that the network device decodes the first part based on a determined length. The network device may determine overheads of a second part based on information in the first part, to decode the second part and obtain information in the CSI report.

Abstract: A channel measurement method and a communications apparatus, the method including generating, by a terminal device, first indication information, where the first indication information indicates one or more component features of a time-varying feature, and further indicates a weighting coefficient of each component feature of the one or more component features, and the one or more component features and the weighting coefficient of each component feature represent the time-varying feature of a channel, and sending, by the terminal device, the first indication information to a network device.

Abstract: Polarization-independent focusing is advantageously achieved by a multifocal system having a polarization beam splitter (PBS) to split an unpolarized light beam into two orthogonally linearly-polarized (LP) light beams. The two LP light beams are reflected by mirrors to travel in opposite directions and enter into a variable-focusing module at two ends thereof, respectively. The module includes waveplates to convert the LP light beams into two circularly-polarized (CP) light beams at both ends of an optical assembly. The optical assembly is formed with a stack of birefringent optical elements including at least one geometric phase lens and one polarization selector that may be electrically modulated to select the optical power in focusing the two CP light beams. Followed by the waveplates converting two focused CP light beams to two focused LP light beams and upon mirror reflection, the beams are finally recombined by the PBS to form one focused light beam.

Abstract: 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 M1 of frequency domain vectors reported for the first-type transport layer satisfies: M 1 = ? p 1 × N 3 R ? , wherein p1 is a preconfigured coefficient for determining the maximum quantity of frequency domain vectors reported for the first-type transport layer, 1?p1>0, R is a preconfigured value, N3 is a length of a frequency domain vector, Z>2, and R, N3, and Z are all positive integers.

Abstract: Example communication methods and communications apparatus are described. One example method include: receiving downlink control information (DCI), where the DCI indicates N demodulation reference signal (DMRS) ports. The N DMRS ports correspond to each of M physical downlink shared channel (PDSCH) transmission units, at least two of the M PDSCH transmission units correspond to different transmission configuration indicator (TCI)-states, N is an integer greater than or equal to 1, and M are integers greater than or equal to 2. M PDSCHs are received based on the DCI.

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: A multilayered optical security device has a resonant waveguide grating (RWG) layer on an under layer having a hologram. The RWG layer has plural RWGs for generating one or more patterns. Each RWG has first and second RWG portions, with diffraction gratings of different grating periods, for light coupling-in and coupling-out, respectively. Using the RWGs minimizes interference to a holographic image generated by the under layer. This advantage is especially useful when the holographic image carries digital data such as in digital holographic encryption where an encrypted hologram is used in the under layer. The digital data may contain biometric information such as a fingerprint. In each RWG portion of an individual RWG, scattering elements in a grating are curved to thereby enhance an angular tolerance in azimuthal angle during observing the patterns by an observer while the individual RWG is still selective in elevation angle.

Abstract: This application provides a communication processing method and apparatus. The method includes: receiving M groups of first parameters and N groups of second parameters that are sent by a network device, where the first parameter is a downlink parameter, the second parameter is a CRS rate matching parameter, M is a positive integer greater than or equal to 2, and N is a positive integer greater than or equal to 1, where there is an association relationship between P groups of first parameters in the M groups of first parameters and the N groups of second parameters, P is less than or equal to M, and P is a positive integer. Terminal devices may determine a punctured time-frequency resource on a PDSCH based on CRS rate matching parameters determined by the terminal devices, to obtain downlink data.

Abstract: This application provides a method for reporting a terminal device capability and a communications apparatus. The method includes: The terminal device generates first indication information and sends the first indication information to a network device. The first indication information is used to indicate one or more frequency domain parameters and one or more of the following capability parameters associated with each frequency domain parameter: a port quantity, a spatial domain parameter, a reference signal resource quantity, and a total port quantity. The frequency domain parameter is used to indicate a maximum quantity of frequency domain units that can be supported by the terminal device. The frequency domain unit is a frequency domain unit based on which the terminal device feeds back a PMI. Each capability parameter group may be used to indicate one combination of a plurality of parameters that can be supported by the terminal device.

Abstract: Embodiments of this application disclose a channel estimation method and apparatus, and relate to the field of communications technologies, to help reduce indication overheads. The method may include: 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: Embodiments of this application provide a downlink control information transmission method, an apparatus, and a system, so that after receiving one piece of DCI, the terminal device learns whether blind detection of DCI needs to be continued. The method includes: A terminal device receives first DCI, where the first DCI includes first indication information, and the first indication information is used to indicate a first antenna port. The terminal device assumes, based on the first antenna port and antenna port configuration information, whether second DCI exists. The configuration information may include an index of a CDM group to which each of a plurality of antenna ports belongs and a maximum quantity of CDM groups that is supported by the terminal device; or the configuration information may include one or more antenna port groups, and each of the one or more antenna port groups includes one or more antenna ports.

Abstract: Embodiments of this application provide a communication method and a communications apparatus. The method includes: determining a plurality of frequency domain units on which reporting of a PMI is based in reporting bandwidth. The plurality of frequency domain units include one or more first frequency domain units and third frequency domain units obtained by dividing one or more second frequency domain units. A granularity of the first frequency domain unit is less than a preconfigured first granularity, a granularity of the second frequency domain unit is a first granularity, and a granularity of the third frequency domain unit is a predetermined second granularity. The first granularity is a granularity preconfigured for reporting a CQI, a second granularity is a granularity predetermined for reporting the PMI, and the second granularity is less than the first granularity.

Abstract: This disclosure provides a method for determining a transport block size (TBS) of a transport block and a communications apparatus. The method includes: A communications apparatus determines a data block size corresponding to each of n code words, where the n code words correspond to a same transport block, and n is an integer greater than 1; and then, the communications apparatus determines a TBS of the transport block based on a data block size of one or more of the n code words.

Abstract: A search space blind detection method and a communication apparatus. The method includes: a terminal receives indication information that corresponds to a first search space set and that is sent by a network device, where the indication information is used to indicate one or more search space groups, one search space group includes at least two search spaces having an association relationship, and at least one search space in one search space group belongs to the first search space set; and then, the terminal determines, based on the indication information, a quantity of blind detection times corresponding to the first search space set. The quantity of blind detection times corresponding to the first search space set is determined by considering an association relationship between a plurality of search spaces.

Abstract: This application provides a multi-downlink control information based transmission technology, in which a terminal reports information about a capability of the terminal to support multi-DCI transmission, or a network device sends indication information of types or a quantity of multi-DCI based transmissions to a terminal, and the network device performs resource scheduling on the terminal on this basis, thereby helping improve resource scheduling efficiency and reduce processing complexity of the terminal. In addition, this application also provides a corresponding solution for a scenario in which a CA/DC based transmission scenario coexists with multi-DCI based transmission, thereby helping the terminal share a multi-DCI based transmission capability and a CA/DC based transmission capability, and improve a processing capability of the terminal.

Abstract: A precoding matrix indicating and determining method, including determining a precoding matrix indicator (PMI) having R groups of space-frequency information corresponding to R transmission layers, where the R groups of space-frequency information are used to determine a precoding matrix of each subband, and an rth group of space-frequency information in the R groups indicates P×L space domain vectors corresponding to an rth transmission layer in the R transmission layers, K frequency domain vectors corresponding to the rth transmission layer, and P×L×K coefficients corresponding to the rth transmission layer, where each of the P×L×K coefficients indicates a linear superposition coefficient of a vector operation result of a P×L space domain vectors and one of the K frequency domain vectors, R is a quantity of transmission layers, P is a quantity of polarization directions, and R, r, P, L, and K are all positive integers, and sending the PMI.