# US 2023/0056714 A1 · Harq process for sidelink transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0056714 A1 - Document ID: US20230056714A1 - Status: Published application - Kind: A1 - Application number: 17/982,372 - Filed: 2022-11-07 - Published: 2023-02-23 - Earliest claimed: 2019-03-22 - Assignees: Lenovo (Singapore) Pte. Ltd. - Applicants: Lenovo (Singapore) Pte. Ltd. - Inventors: Joachim Loehr; Prateek Basu Mallick; Karthikeyan Ganesan; Ravi Kuchibhotla - Web page: https://patentgrep.com/patent/US20230056714A1 ## CPC - H04L 1/1819: {with retransmission of additional or different redundancy} - H04L 1/1822: involving configuration of automatic repeat request [ARQ] with parallel processes - H04L 1/1845: {Combining techniques, e.g. code combining} - H04L 1/1896: {ARQ related signaling} - H04W 4/40: for vehicles, e.g. vehicle-to-pedestrians [V2P] - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04L 2001/0092: {Error control systems characterised by the topology of the transmission link} - H04L 2001/0097: {Relays} - H04W 92/18: between terminal devices - 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 Apparatuses, methods, and systems are disclosed for sidelink HARQ operation. One apparatus includes a memory coupled to a processor, where the processor is configured to cause the second apparatus to receive a SL grant for a SL transmission using SL resources, the SL grant indicating a first HARQ process identified by a first HARQ process identifier, and to select a second SL HARQ process identified by a second SL HARQ process identifier for the SL transmission using the SL resources. The processor is configured to cause the second apparatus to transmit SCI containing the second SL HARQ process identifier and to perform the SL transmission using the SL resources. ## Claims ### Claim 1 An apparatus for wireless communication, the apparatus comprising: a processor; and a memory coupled to the processor, wherein the processor is configured to cause the apparatus to: receive a sidelink (“SL”) grant for a SL transmission using SL resources, the SL grant indicating a first hybrid automatic repeat request (“HARQ”) process identified by a first HARQ process identifier; select a second SL HARQ process identified by a second SL HARQ process identifier for the SL transmission using the SL resources, wherein the second SL HARQ process is selected independently from the first HARQ process in response to the SL grant indicating an SL initial transmission, and wherein the selection of the second SL HARQ process is based on the first HARQ process identifier in response to the SL grant indicating a SL retransmission; transmit SL control information (“SCI”) containing the second SL HARQ process identifier; and perform the SL transmission using the SL resources. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to cause the apparatus to transmit HARQ feedback for the first HARQ process, the HARQ feedback corresponding to the SL transmission using the SL resources. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the SL grant indicates a physical uplink control channel resource and/or HARQ feedback timing information, wherein transmitting the HARQ feedback for the first HARQ process is based on the SL grant. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the first HARQ process identifier received in the SL grant is different than the second SL HARQ process identifier signaled within the SCI. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein, to select the second SL HARQ process, the processor is configured to cause the apparatus to autonomously select a second SL HARQ process from a set of SL HARQ processes. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the set of SL HARQ processes is shared between unicast SL transmissions, groupcast SL transmission, and broadcast SL transmissions. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the selected second SL HARQ process is associated with a second SL HARQ process for which there is no pending SL HARQ retransmission. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to map the first HARQ process to the second SL HARQ process. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to associate the selected second SL HARQ process to the SL grant. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to associate the second SL HARQ Process identifier corresponding to the second SL HARQ process to the SL grant. ### Claim 11 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to select the second SL HARQ process being associated with the SL grant in response to the SL grant indicating a SL retransmission. ### Claim 12 (depends on 1) The apparatus of claim 1, wherein, to perform the SL transmission using the SL resources, the processor is configured to cause the apparatus to transmit the SCI containing the second SL HARQ process identifier for the second SL HARQ process, wherein the processor is further configured to cause the apparatus to receive SL HARQ feedback for the second SL HARQ process from at least one user equipment (“UE”). ### Claim 13 (depends on 12) The apparatus of claim 12, wherein, to perform the SL transmission using the SL resources, the processor is configured to cause the apparatus to perform an initial groupcast transmission, wherein the received SL HARQ feedback comprises a negative acknowledgement indication, and wherein the processor is configured to cause the apparatus to retransmit the SL transmission using unicast SL retransmission. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the unicast SL retransmission reuses the second HARQ process identifier. ### Claim 15 A method of a remote unit comprising: receiving a sidelink (“SL”) grant for a SL transmission using SL resources, the SL grant indicating a first hybrid automatic repeat request (“HARQ”) process identified by a first HARQ process identifier; selecting a second SL HARQ process identified by a second SL HARQ process identifier for the SL transmission using the SL resources, wherein the second SL HARQ process is selected independently from the first HARQ process in response to the SL grant indicating an initial SL transmission, wherein the selection of the second SL HARQ process based on the first HARQ process identifier in response to the SL grant indicating a SL retransmission; transmitting SL control information (“SCI”) containing the selected second SL HARQ process identifier; and performing the SL transmission using the SL resources. ### Claim 16 (depends on 15) The method of claim 15, further comprising associating the selected second SL HARQ process to the SL grant. ### Claim 17 (depends on 15) The method of claim 15, further comprising associating the second SL HARQ Process identifier corresponding to the second SL HARQ process to the SL grant. ### Claim 18 (depends on 15) The method of claim 15, wherein selecting the second SL HARQ process being associated with the SL grant occurs in response to the SL grant indicating a SL retransmission. ### Claim 19 (depends on 15) The method of claim 15, wherein performing the SL transmission using the SL resources comprises transmitting the SCI containing the second SL HARQ process identifier for the second SL HARQ process, the method further comprising receiving SL HARQ feedback for the second SL HARQ process from at least one user equipment (“UE”). ### Claim 20 (depends on 19) The method of claim 19, wherein the SCI further contains a new data indicator (“NDI”), wherein a receiving UE performs the soft-buffer management for the received SL transmission based on at least the second SL HARQ process identifier, the source Identifier (“ID”), and the NDI.