# US 10,374,684 B2 · Transport block retransmission method and base station > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,374,684 B2 - Document ID: US10374684B2 - Status: Granted - Kind: B2 - Application number: 16/194,088 - Filed: 2018-11-16 - Published: 2019-03-21 - Granted: 2019-08-06 - Earliest claimed: 2016-05-17 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Longke He - Web page: https://patentgrep.com/patent/US10374684B2 ## CPC - H04B 7/0697: {using spatial multiplexing} - H04B 7/0413: MIMO systems - H04L 1/0057: {Block codes (H04L1/0061, H04L1/0064 take precedence)} - H04L 1/1819: {with retransmission of additional or different redundancy} - H04L 1/1867: Arrangements specially adapted for the transmitter end - H04W 28/06: Optimizing {the usage of the radio link}, e.g. header compression, information sizing {, discarding information (system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365)} - H04W 76/28: Discontinuous transmission [DTX]; Discontinuous reception [DRX] - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A transport block retransmission method and a base station are described. In the method, for first m retransmissions of a transmission block (TB), a closed-loop spatial multiplexing transmit manner for initial transmission of the TB is maintained. The method may also include, for last N-m retransmissions of the TB, a transmit manner is changed into an open-loop transmit manner when a transmission mode remains unchanged. Retransmission of the TB in the open-loop transmit manner can improve reliability of data transmission, reduce a quantity of retransmissions of the TB, reduce a residual block error rate and a voice packet loss rate, and ensure that a closed-loop gain can be effectively obtained. ## Claims ### Claim 1 A transport block retransmission method, comprising: transmitting, by a base station in an initial transmission, a transport block (TB) to user equipment (UE) using closed-loop spatial multiplexing; when transmission of the TB fails, retransmitting, by the base station, the TB using the closed-loop spatial multiplexing for a first m retransmissions of the TB, wherein m is an integer greater than or equal to 0; and for a last N-m retransmissions of the TB, retransmitting, by the base station, the TB using open-loop spatial multiplexing having a transmission mode (TM) to which the closed-loop spatial multiplexing belongs, wherein N is a maximum quantity of retransmissions of the TB and N is an integer greater than or equal to 1. ### Claim 2 (depends on 1) The method according to claim 1, wherein when the TM is TM4, the closed-loop spatial multiplexing and the open-loop spatial multiplexing are supported in a downlink control information (DCI) format 2. ### Claim 3 (depends on 2) The method according to claim 2, wherein the method further comprises: determining, by the base station, that the initial transmission of the TB uses discontinuous transmission (DTX) and a reason for the first m retransmissions is DTX; and retransmitting, by the base station, the TB using the closed-loop spatial multiplexing for the last N-m retransmissions of the TB. ### Claim 4 (depends on 1) The method according to claim 1, wherein when the TM is TM5, the closed-loop spatial multiplexing is supported in a downlink control information (DCI) format 1D, and the open-loop spatial multiplexing is supported in a DCI format 1A. ### Claim 5 (depends on 1) The method according to claim 1, wherein when the TM is TM6, the closed-loop spatial multiplexing is supported in a downlink control information (DCI) format 1B, and the open-loop spatial multiplexing is supported in a DCI format 1A. ### Claim 6 (depends on 1) The method according to claim 1, wherein when the TM is TM8, the closed-loop spatial multiplexing and the open-loop spatial multiplexing are supported in a downlink control information (DCI) format 2B. ### Claim 7 (depends on 1) The method according to claim 1, wherein when the TM is TM9, the closed-loop spatial multiplexing and the open-loop spatial multiplexing are supported in a downlink control information (DCI) format 2C. ### Claim 8 (depends on 1) The method according to claim 1, wherein when the TM is TM10, the closed-loop spatial multiplexing and the open-loop spatial multiplexing are supported in a downlink control information (DCI) format 2D. ### Claim 9 (depends on 1) The method according to claim 1, wherein a value of m is 2. ### Claim 10 A base station, comprising: a processor configured to control a transceiver to transmit a transport block (TB) to user equipment (UE) using closed-loop spatial multiplexing; and the processor is further configured to: when initial transmission of the TB fails, control the transceiver to retransmit the TB using the closed-loop spatial multiplexing for a first m retransmissions of the TB, wherein m is an integer greater than or equal to 0, and for a last N-m retransmissions of the TB, control the transceiver to retransmit the TB using open-loop spatial multiplexing having a transmission mode (TM) to which the closed-loop spatial multiplexing belongs, wherein N is a maximum quantity of retransmissions of the TB and N is an integer greater than or equal to 1. ### Claim 11 (depends on 10) The base station according to claim 10, wherein when the TM is TM4, the closed-loop spatial multiplexing and the open-loop spatial multiplexing are supported in a downlink control information (DCI) format 2. ### Claim 12 (depends on 11) The base station according to claim 11, wherein the processor is further configured to: determine that the initial transmission of the TB uses discontinuous transmission (DTX) and a reason for the first m retransmissions is DTX; and retransmit the TB using the closed-loop spatial multiplexing for the last N-m retransmissions of the TB. ### Claim 13 (depends on 10) The base station according to claim 10, wherein when the TM is TM5, the closed-loop spatial multiplexing is supported in a downlink control information (DCI) format 1D, and the open-loop spatial multiplexing is supported in a DCI format 1A. ### Claim 14 (depends on 10) The base station according to claim 10, wherein when the TM is TM6, the closed-loop spatial multiplexing is supported in a downlink control information (DCI) format 1B, and the open-loop spatial multiplexing is supported in a DCI format 1A. ### Claim 15 (depends on 10) The base station according to claim 10, wherein when the TM is TM8, the closed-loop spatial multiplexing and the open-loop spatial multiplexing are supported in a downlink control information (DCI) format 2B. ### Claim 16 (depends on 10) The base station according to claim 10, wherein when the TM is TM9, the closed-loop spatial multiplexing and the open-loop spatial multiplexing are transmit manners supported in a downlink control information (DCI) format 2C. ### Claim 17 (depends on 10) The base station according to claim 10, wherein when the TM is TM10, the closed-loop spatial multiplexing and the open-loop spatial multiplexing are supported in a downlink control information (DCI) format 2D. ### Claim 18 (depends on 10) The base station according to claim 10, wherein a value of m is 2.