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: This application relates to the field of communications technologies and provides a quasi co-location indication method and an apparatus, so that a terminal learns of a quasi co-location relationship between a plurality of antenna ports of a first reference signal resource. The method includes: A terminal receives quasi-co-location indication information, where the quasi-co-location indication information is used to indicate M antenna port groups corresponding to a first reference signal resource, each of the M antenna port groups includes one or more CDM groups of the first reference signal resource, the CDM group includes a plurality of antenna ports, and any two antenna ports in a same antenna port group are in a quasi-co-location relationship. Then, the terminal determines a quasi-co-location relationship between a plurality of antenna ports of the first reference signal resource based on the quasi-co-location indication information.

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: Methods, systems, and apparatus for downlink control information (DCI) detection are provided. In one aspect, a DCI detection method includes: receiving a configuration parameter that is used to configure at least one or more groups of candidate resources, each of the one or more groups of candidate resources carrying one piece of DCI, and in response to determining that one corresponding piece of DCI is blindly detected from one of the one or more groups of candidate resources, stopping the blind detection on the one of the one or more groups of candidate resources.

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: Example methods and apparatus for configuring a transmit port of a downlink reference signal are described. One example method includes indicating configurations corresponding to a plurality of transmit ports to a terminal device by a network device by using first indication information. Each transmit port may be associated with one piece of delay information, transmit ports associated with same delay information correspond to a same configuration, and at least two transmit ports associated with different delay information correspond to different configurations. The terminal device may receive, based on a configuration corresponding to each transmit port, downlink reference signals sent by the plurality of transmit ports.

Abstract: This disclosure provides an information transmission method and a communications device. The method includes: when determining that higher layer signaling is not configured with a scrambling identifier, scrambling or descrambling, by a communications device, data by using a second initial scrambling value, where the scrambling identifier is used by the communications device to determine a first initial scrambling value used for data scrambling or descrambling, and the second initial scrambling value is related to at least one or two of a cell identifier, a radio network temporary identifier, and a reserved bit. Therefore, in the embodiments of this disclosure, when determining that the higher layer is not configured with the scrambling identifier, the communications device scrambles or descrambles the data by using the second initial scrambling value. This resolves a problem in the prior art that a terminal device cannot determine an initial scrambling value used for data scrambling.

Abstract: This application provides a resource indication method, a terminal device, and a network device. The method includes: receiving, by the terminal device, the first indication information, and determining time domain positions of demodulation reference signals (DMRSs) based on the mapping type of the physical shared channel and with reference to a position index of the last symbol occupied by the physical shared channel or a quantity of symbols occupied by the physical shared channel in the resource unit, where the position index of the last symbol occupied by the physical shared channel in the resource unit corresponds to the first type, and the quantity of symbols occupied by the physical shared channel in the resource unit corresponds to the second type.

Abstract: Example channel measurement methods and a communication apparatus are described. One example method include receiving a precoded reference signal and indication information by a terminal device, where the indication information is used to indicate a relative delay between a first delay and a second delay, and the first delay and the second delay are determined through uplink channel measurement. The terminal device performs channel measurement based on the precoded reference signal and the indication information.

Abstract: This application provides one or more resource indication methods, terminal devices, and network devices. An example method includes: receiving, by the terminal device, the first indication information, and determining time domain positions of a demodulation reference signal (DMRS) based on the mapping type of the physical shared channel and with reference to a position index of the last symbol occupied by the physical shared channel or a quantity of symbols occupied by the physical shared channel in the resource unit. The position index of the last symbol occupied by the physical shared channel in the resource unit corresponds to the first type, and the quantity of symbols occupied by the physical shared channel in the resource unit corresponds to the second type.

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: 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: Embodiments of this application disclose a method and an apparatus for transmitting a DMRS, and relate to the field of communications technologies. The method and the apparatus are applicable to an NR system. The method for transmitting a DMRS may include: determining a time-frequency resource used to carry a DMRS; and then sending the DMRS by using the time-frequency resource.

Abstract: This application provides a channel measurement method and a communications apparatus. The method includes: A terminal device generates first indication information and sends the first indication information to a network device, where the first indication information is determined based on received precoded reference signals of P ports and is used to indicate Q ports in the P ports; the P ports correspond to P angle-delay pairs; each angle-delay pair includes one angle vector and one delay vector; the precoded reference signal of each of the P ports is obtained by precoding a reference signal based on one angle vector and one delay vector; and the Q ports correspond to Q angle-delay pairs in the P angle-delay pairs.

Abstract: Embodiments of this application disclose a method and an apparatus for transmitting a DMRS, and relate to the field of communications technologies. The method and the apparatus are applicable to an NR system. The method for transmitting a DMRS may include: determining a time-frequency resource used to carry a DMRS; and then sending the DMRS by using the time-frequency resource.

Abstract: This application provides a data transmission method and a device. The method includes: obtaining, by a transmit end device, a modulation symbol sequence in multiple time-frequency resource element groups, wherein a size of the time-frequency resource element group is agreed on in a protocol, or determined based on a transmission parameter; performing, by the transmit end device, interleaving processing on the modulation symbol sequence using the time-frequency resource element group as an interleaving unit, to obtain an order in which the modulation symbol sequence is mapped onto the multiple time-frequency resource element groups, wherein multiple consecutive modulation symbol groups in the modulation symbol sequence are mapped onto at least two of the multiple time-frequency resource element groups; and sending, by the transmit end device, the modulation symbol sequence in the order in which the modulation symbol sequence is mapped onto the multiple time-frequency resource element groups.

Abstract: This application provides a Demodulation Reference Signal (DMRS) transmission method and a communications device. The method includes: determining, by a communications device, a current mode of a resource scheduling unit, where the current mode is a frequency hopping mode or an aggregation mode, and performing, by the communications device, DMRS mapping or demapping by using a DMRS pattern corresponding to the current mode, where a location of a symbol occupied by a DMRS in the DMRS pattern corresponding to the current mode is different from a location of a symbol occupied by a DMRS in a preset DMRS pattern. In embodiments of this application, a location of a symbol occupied by a DMRS can be flexibly selected depending on different modes. Therefore, requirements of the different modes can be satisfied in the embodiments of this application, thereby improving network performance.

Abstract: An apparatus and method are provided for a quantity and size of subbands in a channel state information (CSI) reporting band for flexibility and reduced complexity of terminal addressing. The method includes: determining a channel state information subband size based on a bandwidth part (BWP), determining a quantity of channel state information subbands included in a channel state information reporting band based on (i) a carrier bandwidth (CC bandwidth), (ii) the BWP bandwidth or (iii) a channel state information reference signal (CSI-RS) bandwidth and the channel state information subband size. The method further includes determining an actual quantity of resource blocks included in a starting subband and an actual quantity of resource blocks in an ending subband in the channel state information subband.