# US 12,119,902 B2 · Transmission precoding matrix indication method and device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,119,902 B2 - Document ID: US12119902B2 - Status: Granted - Kind: B2 - Application number: 18/228,195 - Filed: 2023-07-31 - Published: 2023-11-23 - Granted: 2024-10-15 - Earliest claimed: 2017-05-05 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Haibao Ren; Yi Huang; Yuanjie Li - Web page: https://patentgrep.com/patent/US12119902B2 ## CPC - H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting - H04B 7/0478: {Special codebook structures directed to feedback optimisation} - H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection} - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract This application provides a transmission precoding matrix indication method and a device. The method includes: determining a bit quantity of a transmission precoding matrix indicator field corresponding to a subband scheduled for uplink based on downlink control information received from a network device, where the bit quantity of the transmission precoding matrix indicator field corresponding to the subband is related to a quantity of subbands corresponding to the resource scheduled for uplink; and further, determining an uplink transmission precoding matrix corresponding to the subband based on the bit quantity of the transmission precoding matrix indicator field corresponding to the subband and the uplink transmission layer quantity. A transmission precoding matrix indicator field can be effectively used, and control channel resource utilization is improved. ## Claims ### Claim 1 A communications method, comprising: sending downlink control information to a terminal device, wherein the downlink control information comprises an indicator field which is used to indicate an index of an uplink transmission precoding matrix, wherein a bit quantity of the indicator field is related to a quantity of precoding matrices comprised in a codebook subset; and sending, to the terminal device, a configuration message that is used to indicate the codebook subset which the indexed uplink transmission precoding matrix belongs to. ### Claim 2 (depends on 1) The method according to claim 1, further comprising: determining the codebook subset. ### Claim 3 (depends on 2) The method according to claim 2, wherein the configuration message is carried in higher layer signaling. ### Claim 4 (depends on 2) The method according to claim 2, wherein the configuration message comprises at least one bit, and the bit is used to indicate whether at least one transmission precoding matrix corresponding to the bit in a codebook belongs to the codebook subset, and if a value of the bit is equal to a preset value, the at least one transmission precoding matrix corresponding to the bit in the codebook belongs to the codebook subset. ### Claim 5 A communications method, comprising: receiving downlink control information from a network device, wherein the downlink control information comprises an indicator field which is used to indicate an index of an uplink transmission precoding matrix, wherein a bit quantity of the indicator field is related to a quantity of precoding matrices comprised in a codebook subset, and receiving, from the network device, a configuration message that is used to indicate the codebook subset which the indexed uplink transmission precoding matrix belongs to. ### Claim 6 (depends on 5) The method according to claim 5, wherein the configuration message is carried in higher layer signaling. ### Claim 7 (depends on 5) The method according to claim 5, wherein the configuration message comprises at least one bit, and the bit is used to indicate whether at least one transmission precoding matrix corresponding to the bit in the codebook belongs to the codebook subset, and if a value of the bit is equal to a preset value, the at least one transmission precoding matrix corresponding to the bit in the codebook belongs to the codebook subset. ### Claim 8 (depends on 5) The method according to claim 5, further comprising: determining the index of the uplink transmission precoding matrix based on the indicator field. ### Claim 9 A communications apparatus, comprising a processor, wherein the processor is configured to execute instructions stored in a memory to cause the apparatus to send downlink control information to a terminal device, wherein the downlink control information comprises an indicator field which is used to indicate an index of an uplink transmission precoding matrix, wherein a bit quantity of the indicator field is related to a quantity of precoding matrices comprised in a codebook subset; and send, to the terminal device, a configuration message that is used to indicate the codebook subset which the indexed uplink transmission precoding matrix belongs to. ### Claim 10 (depends on 9) The apparatus according to claim 9, wherein the processor is configured to execute further instructions stored in a memory to cause the apparatus to perform the following: determining the codebook subset. ### Claim 11 (depends on 10) The apparatus according to claim 10, wherein the configuration message is carried in higher layer signaling. ### Claim 12 (depends on 10) The apparatus according to claim 10, wherein the configuration message comprises at least one bit, the bit is used to indicate whether at least one transmission precoding matrix corresponding to the bit in a codebook belongs to the codebook subset, and if a value of the bit is equal to a preset value, the at least one transmission precoding matrix corresponding to the bit in the codebook belongs to the codebook subset. ### Claim 13 A communications apparatus, comprising a processor, wherein the processor is configured to execute instructions stored in a memory to cause the apparatus to receive downlink control information from a network device, wherein the downlink control information comprises an indicator field which is used to indicate an index of an uplink transmission precoding matrix, wherein a bit quantity of the indicator field is related to a quantity of precoding matrices comprised in a codebook subset; and receive, from the network device, a configuration message that is used to indicate the codebook subset which the indexed uplink transmission precoding matrix belongs to. ### Claim 14 (depends on 13) The apparatus according to claim 13, wherein the configuration message is carried in higher layer signaling. ### Claim 15 (depends on 13) The apparatus according to claim 13, wherein the configuration message comprises at least one bit, and the bit is used to indicate whether at least one transmission precoding matrix corresponding to the bit in a codebook belongs to the codebook subset, and if a value of the bit is equal to a preset value, the at least one transmission precoding matrix corresponding to the bit in the codebook belongs to the codebook subset. ### Claim 16 (depends on 13) The apparatus according to claim 13, wherein the processor is configured to execute further instructions stored in a memory to cause the apparatus to determine the index of the uplink transmission precoding matrix based on the indicator field. ### Claim 17 (depends on 13) The apparatus according to claim 13, wherein the apparatus is a chip or a circuit for a terminal device, or, the apparatus is the terminal device.