Techniques for transmitting side link HARQ feedback

Abstract

Aspects of the present disclosure generally relate to wireless communications. In some aspects, a user equipment (UE) may determine a plurality of hybrid automatic repeat request (HARQ) feedback for a plurality of sidelink communications. The UE may identify at least a subset of HARQ feedback from the plurality of HARQ feedback based at least in part on the one or more parameters. The UE may transmit at least a subset of HARQ feedback on a sidelink in a HARQ feedback opportunity. Numerous other aspects are provided.

Description

[0001] This divisional application is a divisional application with a filing date of June 17, 2020, application number 202080059313.8, and invention name “Technology for sending sidelink HARQ feedback”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Patent Application No. 62 / 867,756, filed on June 27, 2019, entitled “TECHNIQUES FOR TRANSMITTING SIDELINK HARQ FEEDBACK,” and U.S. Non-Provisional Patent Application No. 16 / 902,928, filed on June 16, 2020, entitled “TECHNIQUES FOR TRANSMITTING SIDELINK HARQ FEEDBACK,” which are expressly incorporated herein by reference. Technical Field

[0004] Aspects of the present disclosure relate generally to wireless communications and to techniques for sending sidelink hybrid automatic repeat request (HARQ) feedback. Background Art

[0005] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

[0006] A wireless communication network may include multiple base stations (BS) that may support communication of multiple user equipments (UEs). User equipments (UEs) may communicate with base stations (BSs) via downlinks and uplinks. A downlink (or forward link) refers to a communication link from a BS to a UE, and an uplink (or reverse link) refers to a communication link from a UE to a BS. As will be described in more detail herein, a BS may be referred to as a Node B, gNB, access point (AP), radio head, transmit receive point (TRP), new radio (NR) BS, 5G Node B, etc.

[0007] The above-mentioned multiple access technologies have been adopted by various telecommunication standards to provide a common protocol that enables different user devices to communicate at municipal, national, regional and even global levels. New Radio (NR), also known as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). NR aims to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and using orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), better integrating with other open standards, and supporting beamforming, multiple input multiple output (MIMO) antenna technology and carrier aggregation. However, with the increasing demand for mobile broadband access, LTE and NR technologies need to be further improved. Preferably, these improvements should be applicable to other multiple access technologies and telecommunication standards that adopt these technologies. Summary of the invention

[0008] In some aspects, a wireless communication method performed by a user equipment (UE) may include determining multiple hybrid automatic repeat request (HARQ) feedbacks for multiple sidelink communications; identifying at least a subset of HARQ feedbacks from the multiple HARQ feedbacks based at least in part on one or more parameters; and sending at least the subset of HARQ feedbacks on a sidelink in a HARQ feedback opportunity.

[0009] In a first aspect, identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks comprises identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks based at least in part on at least one of: determining that the UE cannot send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, determining that the UE is not allowed to send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, detecting a conflict between two or more of the plurality of sidelink communications, or detecting a HARQ feedback conflict in a HARQ feedback opportunity. In a second aspect, either alone or in combination with the first aspect, each of the plurality of HARQ feedbacks comprises a NACK associated with a respective one of the plurality of sidelink communications.

[0010] In a third aspect, alone or in combination with one or more of the first and second aspects, the HARQ feedback in the multiple HARQ feedbacks includes a NACK or ACK associated with each of the multiple sidelink communications. In a fourth aspect, alone or in combination with one or more of the first to third aspects, the method further includes identifying the HARQ feedback opportunity from multiple periodic HARQ feedback opportunities based at least in part on the time domain resource locations of the multiple sidelink communications and the HARQ feedback delay parameters. In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the method further includes, for multiple HARQ feedbacks, identifying each subcarrier set in the HARQ feedback opportunity based at least in part on each subchannel of the sidelink associated with the multiple sidelink communications.

[0011] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, the one or more parameters include at least one of the following: a priority associated with a plurality of sidelink communications, a distance between a UE and one or more other UEs, one or more signal measurements associated with one or more UEs, a frequency domain location of a plurality of HARQ feedbacks, or a transmission mode associated with a plurality of sidelink communications. In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, the one or more parameters include a priority associated with a plurality of sidelink communications, a priority associated with a first sidelink communication in the plurality of sidelink communications being higher than a priority associated with a second sidelink communication in the plurality of sidelink communications, and identifying at least the HARQ feedback subset from the plurality of HARQ feedbacks includes identifying the first HARQ feedback based at least in part on determining that the priority associated with the first sidelink communication is higher than a priority associated with the second sidelink communication.

[0012] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, a priority associated with the first sidelink communication is indicated in sidelink control information (SCI) associated with the first sidelink communication. In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, one or more parameters include priorities associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, wherein the priority associated with the first sidelink communication in the multiple sidelink communications and the priority associated with the second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE in one or more other UEs is shorter than the distance between the UE and a second other UE in one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE.

[0013] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0014] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the one or more parameters include priorities associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater relative to a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

[0015] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0016] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the one or more parameters include priorities associated with a plurality of sidelink communications, and transmission modes associated with the plurality of sidelink communications, wherein the priority associated with a first sidelink communication in the plurality of sidelink communications and the priority associated with a second sidelink communication in the plurality of sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a determination that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority. In a sixteenth aspect, alone or in combination with one or more of the first to fifteenth aspects, the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication include at least one of a unicast transmission mode, a groupcast transmission mode, a multicast transmission mode, or a broadcast transmission mode.

[0017] In a seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, one or more parameters include priorities associated with multiple sidelink communications, and frequency domain locations of multiple HARQ feedbacks, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from the multiple HARQ feedbacks includes determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in the HARQ feedback opportunity based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in the HARQ feedback opportunity.

[0018] In an eighteenth aspect, alone or in combination with one or more of the first to seventeenth aspects, the one or more parameters include a transmission mode associated with a plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback from a plurality of HARQ feedbacks or a second HARQ feedback identified from a plurality of HARQ feedbacks based at least in part on a transmission mode associated with a first sidelink communication associated with a first HARQ feedback in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication associated with a second HARQ feedback in the plurality of sidelink communications.

[0019] In a nineteenth aspect, alone or in combination with one or more of the first to eighteenth aspects, one or more parameters include a transmission mode associated with a plurality of sidelink communications, and a priority associated with the plurality of sidelink communications, a transmission mode associated with a first sidelink communication in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication in the plurality of sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a determination that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode.

[0020] In the twentieth aspect, alone or in combination with one or more of the first to nineteenth aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE among the one or more other UEs is shorter relative to the distance between the UE and a second other UE among the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

[0021] In the twenty-first aspect, alone or in combination with one or more of the first to twentieth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the twenty-second aspect, alone or in combination with one or more of the first to twenty-first aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0022] In the twenty-third aspect, alone or in combination with one or more of the first to twenty-second aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater than a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater than the signal strength measurement associated with the second other UE.

[0023] In a twenty-fourth aspect, alone or in combination with one or more of the first to twenty-third aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a twenty-fifth aspect, alone or in combination with one or more of the first to twenty-fourth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0024] In aspect twenty-six, alone or in combination with one or more of aspects one to twenty-fifth, one or more parameters include priorities associated with a plurality of sidelink communications, and the respective priorities associated with each of the plurality of sidelink communications are indicated in a respective SCI associated with each of the plurality of sidelink communications. In aspect twenty-seven, alone or in combination with one or more of aspects one to twenty-six, one or more parameters include respective priorities associated with each of the plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks includes: for at least a subset of HARQ feedbacks, identifying a HARQ feedback associated with a first sidelink communication having the highest priority among the plurality of sidelink communications; and for at least a subset of HARQ feedbacks, identifying, in order of decreasing priority, HARQ feedbacks associated with one or more second sidelink communications among the plurality of sidelink communications until at least the subset of HARQ feedbacks fills the number of HARQ feedbacks that the UE can send in a HARQ feedback opportunity.

[0025] In some aspects, a UE for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to determine multiple HARQ feedbacks for multiple sidelink communications; identify at least a subset of HARQ feedbacks from the multiple HARQ feedbacks based at least in part on one or more parameters; and send at least the subset of HARQ feedbacks on the sidelink in a HARQ feedback opportunity.

[0026] In a first aspect, identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks comprises identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks based at least in part on at least one of: determining that the UE cannot send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, determining that the UE is not allowed to send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, detecting a conflict between two or more of the plurality of sidelink communications, or detecting a HARQ feedback conflict in a HARQ feedback opportunity. In a second aspect, either alone or in combination with the first aspect, each of the plurality of HARQ feedbacks comprises a NACK associated with a respective sidelink communication of the plurality of sidelink communications.

[0027] In a third aspect, alone or in combination with one or more of the first and second aspects, the HARQ feedback in the multiple HARQ feedbacks includes a NACK or ACK associated with each sidelink communication of the multiple sidelink communications. In a fourth aspect, alone or in combination with one or more of the first to third aspects, the one or more processors are further used to identify the HARQ feedback opportunity from multiple periodic HARQ feedback opportunities based at least in part on the time domain resource locations of the multiple sidelink communications and the HARQ feedback delay parameters. In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the one or more processors are further used to, for multiple HARQ feedbacks, identify each subcarrier set in the HARQ feedback opportunity based at least in part on each subchannel of the sidelink associated with the multiple sidelink communications.

[0028] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, the one or more parameters include at least one of the following: a priority associated with a plurality of sidelink communications, a distance between a UE and one or more other UEs, one or more signal measurements associated with one or more UEs, a frequency domain location of a plurality of HARQ feedbacks, or a transmission mode associated with a plurality of sidelink communications. In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, the one or more parameters include a priority associated with a plurality of sidelink communications, a priority associated with a first sidelink communication in the plurality of sidelink communications being higher than a priority associated with a second sidelink communication in the plurality of sidelink communications, and identifying at least the HARQ feedback subset from the plurality of HARQ feedbacks includes identifying the first HARQ feedback based at least in part on determining that the priority associated with the first sidelink communication is higher than a priority associated with the second sidelink communication.

[0029] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, a priority associated with the first sidelink communication is indicated in an SCI associated with the first sidelink communication. In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, one or more parameters include priorities associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, wherein the priority associated with the first sidelink communication in the multiple sidelink communications and the priority associated with the second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE in the one or more other UEs is shorter than the distance between the UE and a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE.

[0030] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0031] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the one or more parameters include priorities associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater relative to a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

[0032] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0033] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the one or more parameters include priorities associated with a plurality of sidelink communications, and transmission modes associated with the plurality of sidelink communications, wherein the priority associated with a first sidelink communication in the plurality of sidelink communications and the priority associated with a second sidelink communication in the plurality of sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a transmission mode associated with the first sidelink communication and a transmission mode associated with the second sidelink communication based at least in part on a determination that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority. In a sixteenth aspect, alone or in combination with one or more of the first to fifteenth aspects, the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication include at least one of a unicast transmission mode, a groupcast transmission mode, a multicast transmission mode, or a broadcast transmission mode.

[0034] In a seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, one or more parameters include priorities associated with multiple sidelink communications, and frequency domain locations of multiple HARQ feedbacks, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from the multiple HARQ feedbacks includes determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in a HARQ feedback opportunity based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in a HARQ feedback opportunity.

[0035] In an eighteenth aspect, alone or in combination with one or more of the first to seventeenth aspects, the one or more parameters include a transmission mode associated with a plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback from a plurality of HARQ feedbacks or identifying a second HARQ feedback from a plurality of HARQ feedbacks based at least in part on a transmission mode associated with a first sidelink communication associated with a first HARQ feedback in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication associated with a second HARQ feedback in the plurality of sidelink communications.

[0036] In a nineteenth aspect, alone or in combination with one or more of the first to eighteenth aspects, one or more parameters include a transmission mode associated with a plurality of sidelink communications and a priority associated with the plurality of sidelink communications, a transmission mode associated with a first sidelink communication in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication in the plurality of sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a determination that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode.

[0037] In the twentieth aspect, alone or in combination with one or more of the first to nineteenth aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE in the one or more other UEs is shorter relative to the distance between the UE and a second other UE in the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

[0038] In the twenty-first aspect, alone or in combination with one or more of the first to twentieth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the twenty-second aspect, alone or in combination with one or more of the first to twenty-first aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0039] In the twenty-third aspect, alone or in combination with one or more of the first to twenty-second aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater than a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater than the signal strength measurement associated with the second other UE.

[0040] In a twenty-fourth aspect, alone or in combination with one or more of the first to twenty-third aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a twenty-fifth aspect, alone or in combination with one or more of the first to twenty-fourth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0041] In aspect twenty-six, alone or in combination with one or more of aspects one to twenty-fifth, one or more parameters include priorities associated with a plurality of sidelink communications, and the respective priorities associated with each of the plurality of sidelink communications are indicated in a respective SCI associated with each of the plurality of sidelink communications. In aspect twenty-seven, alone or in combination with one or more of aspects one to twenty-six, one or more parameters include respective priorities associated with each of the plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks includes: for at least the subset of HARQ feedbacks, identifying a first sidelink communication having the highest priority among the plurality of sidelink communications; and for at least the subset of HARQ feedbacks, identifying, in order of decreasing priority, HARQ feedbacks associated with one or more second sidelink communications among the plurality of sidelink communications until at least the subset of HARQ feedbacks fills the number of HARQ feedbacks that the UE can send in a HARQ feedback opportunity.

[0042] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of a UE, the one or more instructions may cause the one or more processors to determine multiple HARQ feedbacks for multiple sidelink communications; identify at least a subset of HARQ feedbacks from the multiple HARQ feedbacks based at least in part on one or more parameters; and send at least the subset of HARQ feedbacks on the sidelink in a HARQ feedback opportunity.

[0043] In a first aspect, identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks comprises identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks based at least in part on at least one of: determining that the UE cannot send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, determining that the UE is not allowed to send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, detecting a conflict between two or more of the plurality of sidelink communications, or detecting a HARQ feedback conflict in a HARQ feedback opportunity. In a second aspect, either alone or in combination with the first aspect, each of the plurality of HARQ feedbacks comprises a NACK associated with a respective one of the plurality of sidelink communications.

[0044] In a third aspect, alone or in combination with one or more of the first and second aspects, the HARQ feedback in the multiple HARQ feedbacks includes a NACK or ACK associated with each of the multiple sidelink communications. In a fourth aspect, alone or in combination with one or more of the first to third aspects, when executed by one or more processors, the one or more instructions cause the one or more processors to identify the HARQ feedback opportunity from multiple periodic HARQ feedback opportunities based at least in part on the time domain resource locations of the multiple sidelink communications and the HARQ feedback delay parameters. In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, when executed by one or more processors, the one or more instructions cause the one or more processors to, for multiple HARQ feedbacks, identify each subcarrier set in the HARQ feedback opportunity based at least in part on each subchannel of the sidelink associated with the multiple sidelink communications.

[0045] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, the one or more parameters include at least one of the following: a priority associated with a plurality of sidelink communications, a distance between a UE and one or more other UEs, one or more signal measurements associated with one or more UEs, a frequency domain location of a plurality of HARQ feedbacks, or a transmission mode associated with a plurality of sidelink communications. In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, the one or more parameters include a priority associated with a plurality of sidelink communications, a priority associated with a first sidelink communication in the plurality of sidelink communications being higher than a priority associated with a second sidelink communication in the plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks from the plurality of HARQ feedbacks includes identifying the first HARQ feedback based at least in part on determining that the priority associated with the first sidelink communication is higher than a priority associated with the second sidelink communication.

[0046] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, a priority associated with the first sidelink communication is indicated in an SCI associated with the first sidelink communication. In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, one or more parameters include priorities associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, wherein the priority associated with the first sidelink communication in the multiple sidelink communications and the priority associated with the second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE in the one or more other UEs is shorter than the distance between the UE and a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE.

[0047] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0048] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the one or more parameters include priorities associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater relative to a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

[0049] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0050] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the one or more parameters include priorities associated with a plurality of sidelink communications, and transmission modes associated with the plurality of sidelink communications, wherein the priority associated with a first sidelink communication in the plurality of sidelink communications and the priority associated with a second sidelink communication in the plurality of sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a transmission mode associated with the first sidelink communication and a transmission mode associated with the second sidelink communication based at least in part on a determination that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority. In a sixteenth aspect, alone or in combination with one or more of the first to fifteenth aspects, the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication include at least one of a unicast transmission mode, a groupcast transmission mode, a multicast transmission mode, or a broadcast transmission mode.

[0051] In the seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, one or more parameters include priorities associated with multiple sidelink communications, and frequency domain locations of multiple HARQ feedbacks, the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from the multiple HARQ feedbacks includes, at least in part based on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in the HARQ feedback opportunity and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in the HARQ feedback opportunity.

[0052] In an eighteenth aspect, alone or in combination with one or more of the first to seventeenth aspects, the one or more parameters include a transmission mode associated with a plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback from a plurality of HARQ feedbacks or identifying a second HARQ feedback from a plurality of HARQ feedbacks based at least in part on a transmission mode associated with a first sidelink communication associated with a first HARQ feedback in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication associated with a second HARQ feedback in the plurality of sidelink communications.

[0053] In a nineteenth aspect, alone or in combination with one or more of the first to eighteenth aspects, one or more parameters include a transmission mode associated with a plurality of sidelink communications, and a priority associated with the plurality of sidelink communications, a transmission mode associated with a first sidelink communication in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication in the plurality of sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a determination that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode.

[0054] In the twentieth aspect, alone or in combination with one or more of the first to nineteenth aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE among the one or more other UEs is shorter relative to the distance between the UE and a second other UE among the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

[0055] In a twenty-first aspect, alone or in combination with one or more of the first to twentieth aspects, determining whether a distance between the UE and a first other UE is shorter than a distance between the UE and a second other UE includes determining that the distance between the UE and the first other UE is shorter than a distance between the UE and the second other UE, and identifying a first HARQ feedback or a second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than a distance between the UE and the second other UE. In a twenty-second aspect, alone or in combination with one or more of the first to twenty-first aspects, determining whether a distance between the UE and the first other UE is shorter than a distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than a distance between the UE and the second other UE, and identifying a first HARQ feedback or a second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than a distance between the UE and the second other UE.

[0056] In the twenty-third aspect, alone or in combination with one or more of the first to twenty-second aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater than a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater than the signal strength measurement associated with the second other UE.

[0057] In a twenty-fourth aspect, alone or in combination with one or more of the first to twenty-third aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a twenty-fifth aspect, alone or in combination with one or more of the first to twenty-fourth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0058] In aspect twenty-six, alone or in combination with one or more of aspects one to twenty-fifth, one or more parameters include priorities associated with a plurality of sidelink communications, and the respective priorities associated with each of the plurality of sidelink communications are indicated in a respective SCI associated with each of the plurality of sidelink communications. In aspect twenty-seven, alone or in combination with one or more of aspects one to twenty-six, one or more parameters include respective priorities associated with each of the plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks includes: for at least the subset of HARQ feedbacks, identifying a first sidelink communication having the highest priority among the plurality of sidelink communications; and for at least the subset of HARQ feedbacks, identifying, in order of decreasing priority, HARQ feedbacks associated with one or more second sidelink communications among the plurality of sidelink communications until at least the subset of HARQ feedbacks fills the number of HARQ feedbacks that the UE can send in a HARQ feedback opportunity.

[0059] In some aspects, an apparatus for wireless communication may include components for determining multiple HARQ feedbacks for multiple sidelink communications; components for identifying at least a subset of HARQ feedbacks from the multiple HARQ feedbacks based at least in part on one or more parameters; and components for sending at least the subset of HARQ feedbacks on a sidelink in a HARQ feedback opportunity.

[0060] In a first aspect, identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks comprises identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks based at least in part on at least one of: determining that the UE cannot send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, determining that the UE is not allowed to send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, detecting a conflict between two or more of the plurality of sidelink communications, or detecting a HARQ feedback conflict in a HARQ feedback opportunity. In a second aspect, either alone or in combination with the first aspect, each of the plurality of HARQ feedbacks comprises a NACK associated with a respective one of the plurality of sidelink communications.

[0061] In a third aspect, alone or in combination with one or more of the first and second aspects, the HARQ feedback in the multiple HARQ feedbacks includes a NACK or ACK associated with each of the multiple sidelink communications. In a fourth aspect, alone or in combination with one or more of the first to third aspects, the apparatus includes a component for identifying a HARQ feedback opportunity from a plurality of periodic HARQ feedback opportunities based at least in part on time domain resource locations of the multiple sidelink communications and a HARQ feedback delay parameter. In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the apparatus includes a component for identifying, for multiple HARQ feedbacks, each subcarrier set in the HARQ feedback opportunity based at least in part on each subchannel of the sidelink associated with the multiple sidelink communications.

[0062] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, the one or more parameters include at least one of the following: a priority associated with a plurality of sidelink communications, a distance between a UE and one or more other UEs, one or more signal measurements associated with one or more UEs, a frequency domain location of a plurality of HARQ feedbacks, or a transmission mode associated with a plurality of sidelink communications. In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, the one or more parameters include a priority associated with a plurality of sidelink communications, a priority associated with a first sidelink communication in the plurality of sidelink communications being higher than a priority associated with a second sidelink communication in the plurality of sidelink communications, and identifying at least the HARQ feedback subset from the plurality of HARQ feedbacks includes identifying the first HARQ feedback based at least in part on determining that the priority associated with the first sidelink communication is higher than a priority associated with the second sidelink communication.

[0063] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, a priority associated with the first sidelink communication is indicated in an SCI associated with the first sidelink communication. In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, one or more parameters include priorities associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, wherein the priority associated with the first sidelink communication in the multiple sidelink communications and the priority associated with the second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE in the one or more other UEs is shorter than the distance between the UE and a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE.

[0064] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0065] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the one or more parameters include priorities associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater relative to a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

[0066] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0067] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the one or more parameters include priorities associated with a plurality of sidelink communications, and transmission modes associated with the plurality of sidelink communications, wherein the priority associated with a first sidelink communication in the plurality of sidelink communications and the priority associated with a second sidelink communication in the plurality of sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a determination that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority. In a sixteenth aspect, alone or in combination with one or more of the first to fifteenth aspects, the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication include at least one of a unicast transmission mode, a groupcast transmission mode, a multicast transmission mode, or a broadcast transmission mode.

[0068] In a seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, one or more parameters include priorities associated with multiple sidelink communications, and frequency domain locations of multiple HARQ feedbacks, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from the multiple HARQ feedbacks includes determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in the HARQ feedback opportunity based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in the HARQ feedback opportunity.

[0069] In an eighteenth aspect, alone or in combination with one or more of the first to seventeenth aspects, the one or more parameters include a transmission mode associated with a plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback from a plurality of HARQ feedbacks or identifying a second HARQ feedback from a plurality of HARQ feedbacks based at least in part on a transmission mode associated with a first sidelink communication associated with a first HARQ feedback in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication associated with a second HARQ feedback in the plurality of sidelink communications.

[0070] In a nineteenth aspect, alone or in combination with one or more of the first to eighteenth aspects, one or more parameters include a transmission mode associated with a plurality of sidelink communications, and a priority associated with the plurality of sidelink communications, a transmission mode associated with a first sidelink communication in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication in the plurality of sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a determination that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode.

[0071] In the twentieth aspect, alone or in combination with one or more of the first to nineteenth aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE among the one or more other UEs is shorter relative to the distance between the UE and a second other UE among the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

[0072] In the twenty-first aspect, alone or in combination with one or more of the first to twentieth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the twenty-second aspect, alone or in combination with one or more of the first to twenty-first aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0073] In the twenty-third aspect, alone or in combination with one or more of the first to twenty-second aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater than a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater than the signal strength measurement associated with the second other UE.

[0074] In a twenty-fourth aspect, alone or in combination with one or more of the first to twenty-third aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a twenty-fifth aspect, alone or in combination with one or more of the first to twenty-fourth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0075] In aspect twenty-six, alone or in combination with one or more of aspects one to twenty-fifth, one or more parameters include priorities associated with a plurality of sidelink communications, and the respective priorities associated with each of the plurality of sidelink communications are indicated in a respective SCI associated with each of the plurality of sidelink communications. In aspect twenty-seven, alone or in combination with one or more of aspects one to twenty-six, one or more parameters include respective priorities associated with each of the plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks includes: for at least the subset of HARQ feedbacks, identifying a first sidelink communication having the highest priority among the plurality of sidelink communications; and for at least the subset of HARQ feedbacks, identifying, in order of decreasing priority, HARQ feedbacks associated with one or more second sidelink communications among the plurality of sidelink communications until at least the subset of HARQ feedbacks fills the number of HARQ feedbacks that the UE can send in a HARQ feedback opportunity.

[0076] Aspects generally include methods, apparatus, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and / or processing systems as generally described herein with reference to and illustrated by the accompanying drawings, descriptions, and appendices.

[0077] The features and technical advantages of the examples according to the present disclosure have been outlined quite extensively above so that the following detailed description may be better understood. Other features and advantages will be described below. The disclosed concepts and specific examples may be easily used as a basis for modifying or designing other structures for achieving the same purpose of the present disclosure. Such equivalent structures do not depart from the scope of the appended claims. The features of the concepts disclosed herein, their organization and methods of operation, and associated advantages will be better understood from the following description when considered in conjunction with the accompanying drawings. Each of the accompanying drawings is provided for the purpose of illustration and description and not as a definition of the limitations of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] In order to enable a detailed understanding of the above features of the present disclosure, a more specific description briefly summarized above may be made by reference to various aspects, some of which are shown in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of the present disclosure and should not be considered to limit its scope, as the description may admit of other equally valid aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0079] Figure 1 is a block diagram conceptually illustrating an example of a wireless communication network in accordance with aspects of the present disclosure.

[0080] Figure 2 is a block diagram conceptually illustrating an example of a base station in communication with a user equipment (UE) in a wireless communication network in accordance with aspects of the present disclosure.

[0081] Figure 3A is a block diagram conceptually illustrating an example of a frame structure in a wireless communication network according to aspects of the present disclosure.

[0082] Figure 3B is a block diagram conceptually illustrating an example synchronous communication hierarchy in a wireless communication network in accordance with aspects of the present disclosure.

[0083] Figure 4A-4F is a diagram illustrating one or more examples of transmitting sidelink hybrid automatic repeat request (HARQ) feedback according to aspects of the present disclosure.

[0084] Figure 5 is a diagram illustrating example processes performed, for example, by a UE according to aspects of the present disclosure.

[0085] Figure 6 is a conceptual data flow diagram illustrating the data flow between different modules / components / assemblies in an example apparatus according to aspects of the present disclosure. DETAILED DESCRIPTION

[0086] Various aspects of the present disclosure are described more fully below with reference to the accompanying drawings. However, the present disclosure can be embodied in many different forms and should not be construed as being limited to any specific structure or function presented throughout the present disclosure. On the contrary, these aspects are provided so that the present disclosure will be thorough and complete, and the scope of the present disclosure will be fully conveyed to those skilled in the art. Based on the teachings herein, it should be understood by those skilled in the art that the scope of the present disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of any other aspect of the present disclosure or implemented in combination with any other aspect of the present disclosure. For example, any number of aspects set forth herein can be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such a device or method that uses other structures, functions, or structures and functions outside or outside the various aspects of the present disclosure described herein. It should be understood that any aspect of the disclosure disclosed herein can be embodied by one or more elements of the claims.

[0087] Several aspects of telecommunication systems will now be presented with reference to various devices and techniques. These devices and techniques will be described in the detailed description below and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms and / or the like (collectively referred to as "elements"). These elements may be implemented using hardware, software, or a combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and design constraints imposed on the overall system.

[0088] It should be noted that although aspects may be described herein using terminology generally associated with 3G and / or 4G wireless technologies, aspects of the present disclosure may be applied to other generation-based communication systems, such as 5G and higher, including NR technologies.

[0089] Figure 1 is a diagram showing a wireless network 100 in which aspects of the present disclosure may be implemented. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. The wireless network 100 may include a plurality of BSs 110 (shown as BS110a, BS110b, BS110c, and BS110d) and other network entities. A BS is an entity that communicates with a user equipment (UE) and may also be referred to as a base station, NR BS, Node B, gNB, 5G node B (NB), access point, transmit receive point (TRP), etc. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to the coverage area of ​​a BS and / or BS subsystem serving that coverage area, depending on the context in which the term is used.

[0090] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs through service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs through service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown, BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "Node B", "5G NB", and "cell" may be used interchangeably herein.

[0091] In some aspects, the cell is not necessarily stationary, and the geographic area of ​​the cell may move according to the location of the mobile BS. In some aspects, the BSs may be interconnected with each other and / or to one or more other BSs or network nodes (not shown) in the access wireless network 100 through various types of backhaul interfaces (e.g., direct physical connections, virtual networks, etc.) using any suitable transport network.

[0092] The wireless network 100 may also include a relay station. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., a BS or a UE) and send transmissions of data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown, a relay station 110d may communicate with the macro BS 110a and the UE 120d to facilitate communication between the BS 110a and the UE 120d. A relay station may also be referred to as a relay BS, a relay base station, a relay, or the like.

[0093] The wireless network 100 may be a heterogeneous network including different types of BSs, such as a macro BS, a pico BS, a femto BS, a relay BS, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmit power level (e.g., 0.1 to 2 watts).

[0094] A network controller 130 may be coupled to a set of BSs and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with each other directly or indirectly, for example, via a wireless or wired backhaul.

[0095] UE 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. A UE may communicate with one or more BSs in the wireless network 100, may communicate directly with another UE (e.g., UE 120a and UE 120e, such as UE 120a) via a side link, etc. Figure 1 ) communication. UE may also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. A UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, a biometric sensor / device, a wearable device (smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device or a satellite radio), a vehicle component or sensor, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium.

[0096] Some UEs may be considered as machine type communication (MTC) or evolved or enhanced machine type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which may communicate with a base station, another device (e.g., a remote device), or some other entity. For example, a wireless node may provide a connection to or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered as Internet of Things (IoT) devices, and / or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered as customer premises equipment (CPE). UE 120 may be included in a housing that houses components of UE 120 (e.g., processor components, memory components, etc.).

[0097] Generally, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific RAT and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, frequency channel, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0098] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly (e.g., without using base station 110 as an intermediary to communicate with each other) using one or more sidelink channels. For example, UE 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocol (e.g., which may include vehicle-to-vehicle (V2V) protocol, vehicle-to-infrastructure (V2I) protocol, etc.), mesh network, etc. In this case, UE 120 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein as being performed by base station 110.

[0099] As shown above, provide Figure 1 As an example. Other examples may be related to Figure 1 Different than described.

[0100] Figure 2 A block diagram of a design 200 of a base station 110 and a UE 120 is shown, which may be Figure 1 Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T≥1 and R≥1.

[0101] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS selected for the UE, and provide data symbols for all UEs. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI), etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS)) and synchronization signals (e.g., primary synchronization signals (PSS) and secondary synchronization signals (SSS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, if applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a to 232t may be transmitted via T antennas 234a to 234t, respectively. According to various aspects described in more detail below, position coding may be used to generate synchronization signals to convey additional information.

[0102] At the UE 120, antennas 252a to 252r may receive downlink signals from the base station 110 and / or other base stations and may provide received signals to demodulators (DEMODs) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., with OFDM) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE 120 to a data sink 260, and provide decoded control information and system information to a controller / processor 280. The channel processor may determine reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), channel quality indicator (CQI), etc. In some aspects, one or more components of UE 120 may be included in a housing.

[0103] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.). The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 (if applicable), further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to the base station 110. At the base station 110, uplink signals from the UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by MIMO detector 236 (if applicable), and further processed by a receive processor 238 to obtain decoded data and control information transmitted by the UE 120. The receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to the controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292.

[0104] The controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component(s) of the base station 110 may perform one or more techniques associated with sending sidelink hybrid automatic repeat request (HARQ) feedback, as described in more detail elsewhere herein. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component of the can perform or direct e.g. Figure 5 The operations of the process 500 and / or other processes as described herein. The memories 242 and 282 may store data and program codes for the base station 110 and the UE 120, respectively. In some aspects, the memory 242 and / or the memory 282 may include a non-transitory computer-readable medium storing one or more instructions for wireless communication. For example, when executed by one or more processors of the base station 110 and / or the UE 120, the one or more instructions may perform or direct, for example, Figure 5 The operations of the process 500 and / or other processes as described herein. The scheduler 246 can schedule UEs to transmit data on the downlink and / or uplink.

[0105] In some aspects, the UE 120 may include means for determining a plurality of HARQ feedbacks for a plurality of sidelink communications, means for identifying at least a subset of HARQ feedbacks from the plurality of HARQ feedbacks based at least in part on one or more parameters, means for sending at least the subset of HARQ feedbacks on the sidelink in a HARQ feedback opportunity, etc. In some aspects, such means may include combining Figure 2 One or more components of UE 120 are depicted, such as controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, etc.

[0106] As mentioned above, providing Figure 2 As an example. Other examples may be related to Figure 2 Different than described.

[0107] Figure 3A An example frame structure 300 for frequency division duplex (FDD) in a telecommunication system (e.g., NR) is shown. The transmission timeline for each of the downlink and uplink may be divided into units of radio frames (sometimes referred to as frames). Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be divided into a set of Z (Z ≥ 1) subframes (e.g., with indices from 0 to Z-1). Each subframe may have a predetermined duration (e.g., 1 ms) and may include a set of time slots (e.g., Figure 3A 2m time slots per subframe are shown in FIG, where m is a parameter set for transmission, such as 0, 1, 2, 3, 4, etc.). Each time slot may include a set of L symbol periods. For example, each time slot may include fourteen symbol periods (e.g., Figure 3A ), seven symbol periods, or another number of symbol periods. In the case where a subframe includes two slots (e.g., when m=1), the subframe may include 2L symbol periods, where the 2L symbol periods in each subframe may be assigned indices from 0 to 2L–1. In some aspects, the scheduling unit for FDD may be frame-based, subframe-based, slot-based, symbol-based, etc.

[0108] Although some techniques are described herein in conjunction with frames, subframes, time slots, etc., these techniques may be equally applicable to other types of wireless communication structures that may be referred to using terms other than "frames," "subframes," "time slots," etc. in 5G NR. In some aspects, a periodic time-limited communication unit defined by a wireless communication standard and / or protocol may be referred to as a wireless communication structure. Additionally or alternatively, a wireless communication structure may be used in conjunction with Figure 3A The configurations of different wireless communication structures are shown in .

[0109] In some aspects, a UE (e.g., UE 120a, UE 120e, etc.) may send one or more sidelink communications on a sidelink to another UE (e.g., UE 120a, UE 120e, etc.). The UE may send the one or more sidelink communications in one or more time slots included in the frame structure 300, in one or more subcarriers or subchannels included in the frame structure 300, etc. In some aspects, another UE may receive the one or more sidelink communications, may generate HARQ feedback for the one or more sidelink communications, may incorporate the HARQ feedback into one or more HARQ feedback communications, and may send one or more HARQ feedback communications on the sidelink to the UE in a reporting period or HARQ opportunity in the frame structure 300 configured for the sidelink.

[0110] In some telecommunications (e.g., NR), a base station may send synchronization signals. For example, a base station may send a primary synchronization signal (PSS), a secondary synchronization signal (SSS), etc. on the downlink for each cell supported by the base station. The PSS and SSS may be used by the UE for cell search and acquisition. For example, the PSS may be used by the UE to determine symbol timing, and the SSS may be used by the UE to determine the physical cell identifier and frame timing associated with the base station. The base station may also send a physical broadcast channel (PBCH). The PBCH may carry some system information, such as system information that supports initial access of the UE.

[0111] In some aspects, a base station may transmit a PSS, SSS, and / or PBCH according to a synchronization communication hierarchy (e.g., a synchronization signal (SS) hierarchy) including a plurality of synchronization communications (e.g., SS blocks), as described below in conjunction with Figure 3B described.

[0112] Figure 3B is a block diagram conceptually illustrating an example SS hierarchy as an example of a synchronous communication hierarchy. Figure 3B As shown, the SS hierarchy may include an SS burst set, which may include a plurality of SS bursts (identified as SS burst 0 to SS burst B-1, where B is the maximum number of repetitions of the SS burst that may be sent by the base station). As further shown, each SS burst may include one or more SS blocks (identified as SS block 0 to SS block (b max_SS -1), where b max_SS -1 is the maximum number of SS blocks that can be carried by an SS burst). In some aspects, different SS blocks may be beamformed differently. A set of SS bursts may be sent by a wireless node periodically, for example, once every X milliseconds, such as Figure 3B In some aspects, the SS burst set may have a fixed or dynamic length. Figure 3B Shown in Y milliseconds.

[0113] Figure 3B The SS burst set shown is an example of a synchronous communication set, and other synchronous communication sets may be used in conjunction with the techniques described herein. Figure 3B The SS blocks shown are examples of synchronous communications, and other synchronous communications may be used in conjunction with the techniques described herein.

[0114] In some aspects, an SS block includes resources that carry PSS, SSS, PBCH, and / or other synchronization signals (e.g., a third synchronization signal (TSS)) and / or synchronization channels. In some aspects, multiple SS blocks are included in an SS burst, and the PSS, SSS, and / or PBCH may be the same on each SS block of the SS burst. In some aspects, a single SS block may be included in an SS burst. In some aspects, the length of the SS block may be at least four symbol periods, where each symbol carries one or more of the PSS (e.g., occupying one symbol), the SSS (e.g., occupying one symbol), and / or the PBCH (e.g., occupying two symbols).

[0115] In some aspects, the symbols of the SS blocks are consecutive, such as Figure 3B As shown. In some aspects, the symbols of the SS blocks are non-contiguous. Similarly, in some aspects, one or more SS blocks of an SS burst may be sent in continuous radio resources (e.g., continuous symbol periods) during one or more time slots. Additionally or alternatively, one or more SS blocks of an SS burst may be sent in non-contiguous radio resources.

[0116] In some aspects, an SS burst may have a burst period, whereby the base station transmits an SS block of the SS burst according to the burst period. In other words, the SS block may be repeated during each SS burst. In some aspects, an SS burst set may have a burst set period, whereby the base station transmits an SS burst of the SS burst set according to a fixed burst set period. In other words, the SS burst may be repeated during each SS burst set.

[0117] The base station may send system information, such as system information blocks (SIBs), on a physical downlink shared channel (PDSCH) in certain time slots. The base station may send control information / data on a physical downlink control channel (PDCCH) in C symbol periods of a time slot, where B may be configured for each time slot. The base station may send traffic data and / or other data on the PDSCH in the remaining symbol periods of each time slot.

[0118] As shown above, provide Figure 3A and 3B As an example. Other examples can be related to Figure 3A and 3B Different than described.

[0119] In some cases, two or more slave entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relay, V2X communications, Internet of Everything (IoE) communications, IoT communications, mission-critical meshing, and / or various other suitable applications. Communications sent from one slave entity (e.g., UE1) to another slave entity (e.g., UE2) without being relayed by a scheduling entity (e.g., UE or BS) may be referred to as sidelink communications, even if the scheduling entity may be used for scheduling and / or control purposes. In some examples, sidelink communications may be sent using licensed spectrum, unlicensed spectrum (e.g., Industrial, Scientific, and Medical (ISM) radio bands, such as 5 GHZ, which are reserved for purposes other than cellular communications such as Wi-Fi).

[0120] In some cases, a UE may provide feedback to another UE associated with a sidelink communication received from another UE on a sidelink between the UE and the other UE. The feedback may include, for example, HARQ feedback (e.g., an acknowledgment (ACK) or negative acknowledgment (NACK) of the sidelink communication). The UE may send HARQ feedback in one or more HARQ feedback communications on the sidelink. In some cases, the frame structure of the sidelink may include a HARQ feedback opportunity that can be used to send one or more HARQ feedback communications. Unlike a cellular communication link with a BS in which a UE can provide HARQ feedback to a single BS, in a HARQ feedback opportunity, a UE may be allowed to provide HARQ feedback to multiple UEs on a sidelink. However, if the amount of HARQ feedback provided by the scheduling UE is greater than the amount of HARQ feedback that the UE can and / or is allowed to send in the HARQ feedback opportunity, the UE may not be able to determine which HARQ feedback to send in the HARQ feedback opportunity.

[0121] Some aspects described herein provide techniques and apparatus for sending sidelink HARQ feedback. In some aspects, a UE may receive multiple sidelink communications on a sidelink. If the UE determines that the UE is unable and / or is not allowed to send HARQ feedback for all sidelink communications in a HARQ feedback opportunity, the UE may use the techniques described herein to identify a subset of HARQ feedback to be sent in a HARQ feedback opportunity. In this way, the UE may multiplex HARQ feedback in a HARQ feedback opportunity, may identify a subset of HARQ feedback to be multiplexed in a HARQ feedback opportunity, and so on.

[0122] Figure 4A-4F 4 is a diagram illustrating one or more examples 400 of transmitting sidelink HARQ feedback according to aspects of the present disclosure. Figure 4A-4FAs shown, example 400 may include multiple UEs (e.g., UE 120), such as UE1 and UE2. However, in some aspects, a larger number of UEs may be included in example 400. UE1 and UE2 may be included in a wireless network (e.g., wireless network 100) and may communicate via a sidelink. In some aspects, the sidelink may be configured with a frame structure, such as Figure 3A The frame structure 300 and / or the other side link frame structure.

[0123] like Figure 4A As shown, and by reference numeral 402, UE1 and UE2 may communicate via a sidelink by sending and / or receiving sidelink communications via a sidelink. For example, UE1 may receive multiple sidelink communications on the sidelink from one or more UEs including UE2. In some aspects, UE1 may receive multiple sidelink communications on the sidelink from multiple UEs including UE2. In this case, each of the multiple UEs may send one or more of the multiple sidelink communications to UE1.

[0124] In some aspects, multiple sidelink communications may be sent on one or more channels or subchannels of the sidelink. In this case, each sidelink communication may be sent in one or more time domain resources (e.g., across one or more time slots, across one or more symbols, etc.) and / or in one or more frequency domain resources (e.g., in a subchannel of the frequency bandwidth of the sidelink). In some aspects, a subchannel may include multiple subcarriers of the frequency bandwidth sidelink, one or more resource blocks of the frequency bandwidth of the sidelink, etc.

[0125] like Figure 4A As further shown in the figure, and by reference numeral 404, UE1 can determine multiple HARQ feedbacks for multiple sidelink communications. The HARQ feedback for the sidelink communication may include ACK or NACK. ACK can indicate to the transmitter of the sidelink communication (e.g., UE2 or another UE) that the sidelink communication is successfully received and decoded. NACK can indicate to the transmitter of the sidelink communication (e.g., UE2 or another UE) that the sidelink communication is not successfully received and / or decoded. In some aspects, if UE1 is able to decode the control information of the sidelink communication (e.g., sidelink control information (SCI)) and the corresponding data of the sidelink communication, UE1 can determine that the HARQ feedback is ACK. In some aspects, if UE1 cannot decode the control information of the sidelink communication (e.g., SCI), the corresponding data of the sidelink communication, or both the control information and the corresponding data, UE1 can determine that the HARQ feedback is NACK.

[0126] In some aspects, UE1 and UE2 may communicate using an ACK / NACK HARQ feedback configuration, wherein a receiver UE (e.g., UE1 or UE2) will send an ACK based at least in part on successfully receiving and decoding sidelink communications from a transmitter UE (e.g., UE1 or UE2), and will send a NACK for sidelink communications that the receiver UE cannot decode. In some aspects, UE1 and UE2 may communicate using a NACK-only HARQ feedback configuration, wherein a transmitter UE (e.g., UE1 or UE2) does not send HARQ feedback for successfully received and decoded sidelink communications, and only sends a NACK for sidelink communications that the receiver UE cannot decode.

[0127] In some aspects, UE1 may be configured to provide HARQ feedback to UE2 based at least in part on whether the distance between UE1 and UE2 satisfies a distance threshold, and / or whether a signal strength measurement associated with UE2 satisfies a signal strength threshold. For example, UE1 may be configured to provide HARQ feedback to UE2 based at least in part on determining whether the distance between UE1 and UE2 satisfies a distance threshold or does not satisfy the distance threshold. UE1 may determine the distance based at least in part on round trip time (RTT) and / or another type of distance measurement, may receive a distance indication from UE2 and / or another entity, may receive a location indication of UE2, and may determine the distance based at least in part on the location of UE2 and the location of UE1, etc. As another example, UE1 may be configured to provide HARQ feedback to UE2 based at least in part on determining whether a signal strength measurement satisfies a signal strength threshold or does not satisfy a signal strength threshold. UE1 may perform one or more signal strength measurements, such as RSRP measurements, RSSI measurements, etc.

[0128] like Figure 4A As further shown in and by reference numeral 406, UE1 may identify a HARQ feedback opportunity and one or more subcarrier sets in the HARQ feedback opportunity for HARQ feedback associated with one or more sidelink communications. Figure 4B and Figure 4C An example configuration of HARQ feedback opportunities is shown. Other examples of configurations for HARQ feedback opportunities may be used.

[0129] like Figure 4BAs shown in the example configuration in , the HARQ feedback opportunity may include a time domain duration (e.g., one or more symbols) and multiple frequency domain resources (e.g., multiple subcarriers) reserved for HARQ feedback on the sidelink. In some aspects, the frame structure of the sidelink may include multiple HARQ feedback opportunities. Multiple HARQ feedback opportunities may be periodic (e.g., may occur at specific time intervals), may be configured at specific time domain locations, etc. In some aspects, the HARQ feedback opportunity may be a multi-slot HARQ feedback opportunity, because the HARQ feedback opportunity may be used to aggregate HARQ feedback of sidelink communications sent in multiple subchannels and multiple time slots that occurred before the HARQ feedback opportunity. In this way, UE1 can use the HARQ feedback opportunity to FDM and send HARQ feedback within multiple time slots and multiple subchannels.

[0130] The plurality of time slots corresponding to the HARQ feedback opportunities may be referred to as a transmission period of the HARQ feedback opportunities. HARQ feedback for sidelink communications sent during the transmission period may be sent in the HARQ feedback opportunities associated with the transmission period. Figure 4B In the example shown, the transmission period for the example HARQ feedback opportunity can span 2 time slots and 10 subchannels. In this example, the transmission period for the example HARQ feedback opportunity can include 20 time-frequency resources (e.g., subchannel / time slot 0 to subchannel / time slot 19) in which the sidelink communication can be sent.

[0131] In some aspects, UE1 may identify a HARQ feedback opportunity for sending HARQ feedback for sidelink communication based at least in part on a time domain resource location of the sidelink communication (e.g., a time slot in which the sidelink communication is received, a last time slot or an end time slot of a multi-slot sidelink communication, etc.). For example, UE1 may determine that a time domain resource location of the sidelink communication (e.g., a time slot in which the sidelink communication is received, a first time slot or a start time slot of a multi-slot sidelink communication, a last time slot or an end time slot of a multi-slot sidelink communication, etc.) is mapped to a specific HARQ feedback opportunity (e.g., included in a transmission period associated with the HARQ feedback opportunity). As another example, UE1 may determine the HARQ feedback opportunity based at least in part on a HARQ feedback processing capability of the UE (e.g., the amount of time it takes UE1 to determine and send HARQ feedback for the sidelink communication). As another example, UE1 may determine the HARQ feedback timing based at least in part on a HARQ feedback delay parameter configured for the wireless network (e.g., a system-wide delay between receiving the sidelink communication and sending the HARQ feedback for the sidelink communication). Thus, UE1 may determine the HARQ feedback timing as the next HARQ feedback timing that occurs in the time domain relative to when the sidelink communication is received, or may determine the HARQ feedback timing as the HARQ feedback timing that occurs m time slots after the time slot in which the sidelink communication is received.

[0132] like Figure 4B As further shown in, multiple frequency domain resources in the HARQ feedback opportunity can be divided into multiple subcarrier sets. As an example, the HARQ feedback opportunity may include a first subcarrier set 0, a second subcarrier set 1, and so on. Multiple subcarrier sets can be frequency-division multiplexed at the HARQ feedback opportunity. Each subcarrier set may include a corresponding plurality of subcarriers. In some aspects, multiple subcarriers included in a subcarrier set in the HARQ feedback opportunity may be exclusive to the subcarrier set. In this case, in the HARQ feedback opportunity, the subcarriers included in the multiple subcarriers are not included in another subcarrier set. In addition, Figure 4B In the example configuration shown, the plurality of subcarriers in the subcarrier set may be non-contiguous subcarriers that are spaced apart at the HARQ feedback occasions to form a frequency comb. The plurality of subcarriers in the subcarrier set may be spaced apart unevenly across the frequency bandwidth of the HARQ feedback occasions (e.g., some subcarriers in the subcarrier set may be spaced apart by a different number of subcarriers relative to other subcarriers in the subcarrier set), the plurality of subcarriers in the subcarrier set may be spaced apart evenly across the frequency bandwidth of the HARQ feedback occasions, or a combination thereof.

[0133] In some aspects, each subcarrier set in the HARQ feedback opportunity may be associated with a time-frequency resource in a transmission period associated with the HARQ feedback opportunity. UE1 may receive a HARQ configuration (e.g., from UE2, from another UE, from a BS in a wireless network, etc.) identifying a mapping between subcarrier sets and time-frequency resources, and may perform hard encoding and decoding with the HARQ configuration (e.g., the HARQ configuration may be stored on UE1 before UE1 is deployed in the wireless network), etc. Therefore, UE1 may identify a subcarrier set for sending HARQ feedback for sidelink communication in a HARQ feedback opportunity based at least in part on the time domain resources (e.g., time slots) and frequency domain resources (e.g., subchannels) of the received sidelink communication.

[0134] As an example above, subchannel / time slot 0 may be associated with subcarrier set 0, subchannel / time slot 1 may be associated with subcarrier set 1, subchannel / time slot 2 may be associated with subcarrier set 2, subchannel / time slot 3 may be associated with subcarrier set 3, etc. In some aspects, the time-frequency resources in a transmission period may be allocated as column-major sets of subcarriers (e.g., as Figure 4B In some aspects, the time-frequency resources in a transmission period may be allocated as row-based subcarrier sets, wherein all time-frequency resources in a subchannel in a transmission period are mapped to subcarrier sets before proceeding to the next subchannel to map the time-frequency resources to the subcarrier sets.

[0135] In some aspects, UE1 may identify a subcarrier set for sending HARQ feedback for sidelink communications based at least in part on the time-frequency resources in which the sidelink communications are received. In this case, the HARQ feedback for each sidelink communication may be associated with a corresponding subcarrier set. For example, UE1 may identify subcarrier set 0 for HARQ feedback for sidelink communications received in subchannel / time slot 0, may identify subcarrier set 1 for HARQ feedback for sidelink communications received in subchannel / time slot 1, may identify subcarrier set 2 for HARQ feedback for sidelink communications received in subchannel / time slot 2, and so on. Therefore, UE1 may identify a corresponding subcarrier set for sending HARQ feedback for one or more sidelink communications in a HARQ feedback opportunity based at least in part on the time-frequency resources in which the one or more sidelink communications are received.

[0136] In some aspects, the transmission of the sidelink communication may span multiple time slots. In this case, the sidelink communication may be referred to as a multi-slot sidelink communication. UE1 may determine a set of subcarriers for HARQ feedback for the multi-slot sidelink communication, which may be determined at least in part based on a first time slot or a starting time slot of the multi-slot sidelink communication, or may be determined at least in part based on a last time slot or an ending time slot of the multi-slot sidelink communication.

[0137] like Figure 4C As shown in the example configuration in , the multiple subcarriers in the subcarrier set may be adjacent subcarriers. For example, the multiple subcarriers included in the subcarrier set 0 may form a group of continuous and / or consecutive subcarriers, the multiple subcarriers included in the subcarrier set 1 may form another group of continuous and / or consecutive subcarriers, and so on. The groups of consecutive subcarriers may be non-overlapping, so that any subcarrier in the HARQ feedback opportunity is included in only one subcarrier set.

[0138] like Figure 4D As shown, and by reference numeral 408, UE1 may identify at least a subset of the multiple HARQ feedbacks. UE1 may identify a subset of HARQ feedbacks due to various reasons. For example, if UE1 is scheduled to provide multiple HARQ feedbacks in a HARQ feedback opportunity, UE1 may determine that UE1 cannot send all of the multiple HARQ feedbacks in the HARQ feedback opportunity (e.g., based at least in part on the HARQ processing capability of UE1). Therefore, UE1 may identify a subset of HARQ feedbacks that UE1 may be able to send in a HARQ feedback opportunity.

[0139] As another example, if UE1 is scheduled to provide multiple HARQ feedbacks in a HARQ feedback opportunity, UE1 may determine that UE1 is not allowed to send all of the multiple HARQ feedbacks in the HARQ feedback opportunity (e.g., based at least in part on a parameter that specifies a maximum number of HARQ feedbacks that may be configured by the BS and / or another component in the wireless network). Accordingly, UE1 may identify a subset of HARQ feedbacks that UE1 may be allowed to send in the HARQ feedback opportunity.

[0140] As another example, UE1 may detect a conflict between two or more sidelink communications and / or a HARQ feedback conflict associated with two or more sidelink communications. In this case, UE1 may receive two other sidelink communications from multiple UEs in the same time domain resources and frequency domain resources (e.g., this may be referred to as a conflict). Since time domain resources and frequency domain resources may be mapped to a subcarrier set in a HARQ feedback opportunity, and since UE1 may be allowed to provide HARQ feedback to only one sidelink communication in the subcarrier set, two or more sidelink communications may result in a HARQ feedback conflict. Therefore, UE1 may determine whether to discard or drop one or more of the sidelink communications so that the HARQ feedback for the remaining sidelink communications is included in the HARQ feedback subset.

[0141] In some aspects, UE1 may identify a HARQ feedback subset of a plurality of HARQ feedbacks based at least in part on one or more parameters for identifying the HARQ feedback subset. In some aspects, the one or more parameters may be included in the HARQ configuration described above, in another configuration received at UE1 and / or hardcoded for UE1, etc. UE1 may determine which HARQ feedback of the plurality of HARQ feedbacks to include in the HARQ feedback subset for transmission in the HARQ feedback opportunity based at least in part on the one or more parameters.

[0142] In some aspects, the one or more parameters may include parameters for priorities associated with multiple sidelink communications, parameters for the distance between UE1 and a UE sending multiple sidelink communications (e.g., UE2 and / or other UEs), parameters for one or more signal measurements associated with the UE sending multiple sidelink communications, parameters for frequency domain locations of multiple HARQ feedbacks, parameters for a transmission mode associated with multiple sidelink communications, and the like.

[0143] In some aspects, UE1 may use various techniques to identify a subset of HARQ feedback based at least in part on a corresponding priority associated with each of a plurality of sidelink communications. In some aspects, the priority may include a channel priority or another type of priority associated with a plurality of sidelink communications. For example, UE1 may determine that the priority associated with a first sidelink communication is higher than the priority associated with a second sidelink communication, and may identify or select HARQ feedback for the first sidelink communication to be included in the subset of HARQ feedback. As another example, a parameter for a priority associated with a plurality of sidelink communications may indicate that UE1 will start with the HARQ feedback of the sidelink communication with the highest priority, and will identify or select HARQ feedback associated with sidelink communications with gradually decreasing priorities until the subset of HARQ feedback fills the number of HARQ feedbacks that UE1 is able to and / or allowed to be sent in the HARQ feedback opportunity. As another example, a parameter for a priority associated with a plurality of sidelink communications may indicate that UE1 will identify or select HARQ feedback associated with a sidelink communication with a priority that satisfies a priority threshold.

[0144] In some aspects, UE1 may determine a priority of a sidelink communication among a plurality of sidelink communications based at least in part on an SCI associated with the sidelink communication. For example, the SCI may be included in a control portion associated with a data portion of the sidelink communication, and the SCI may include a field or value indicating or specifying a priority of the sidelink communication.

[0145] In some aspects, UE1 may identify a subset of HARQ feedback based at least in part on respective distances between UE1 and UEs that transmit multiple sidelink communications. For example, UE1 may determine that a distance between UE1 and a first UE that transmits a first sidelink communication is greater than a distance between UE1 and a second UE that transmits a second sidelink communication, and may identify or select HARQ feedback for the first sidelink communication to be included in the HARQ feedback subset based at least in part on the distance between UE1 and the first UE being greater than a distance between UE1 and the second UE. As another example, UE1 may determine that a distance between UE1 and a first UE that transmits a first sidelink communication is shorter than a distance between UE1 and a second UE that transmits a second sidelink communication, and may identify or select HARQ feedback for the first sidelink communication to be included in the HARQ feedback subset based at least in part on the distance between UE1 and the first UE being shorter than a distance between UE1 and the second UE.

[0146] As another example, a parameter of the distance between UE1 and a UE that sends multiple sidelink communications may indicate that UE1 will start with the HARQ feedback of the sidelink communication associated with the UE farthest from UE1, and will identify or select the HARQ feedback associated with the sidelink communication associated with the UE whose distance from UE1 gradually decreases until the HARQ feedback subset fills the number of HARQ feedback that UE1 is able and / or allowed to send in the HARQ feedback opportunity. As another example, a parameter of the distance between UE1 and a UE that sends multiple sidelink communications may indicate that UE1 will start with the HARQ feedback of the sidelink communication associated with the UE closest to UE1, and will identify or select the HARQ feedback associated with the sidelink communication associated with the UE whose distance from UE1 gradually increases until the HARQ feedback subset fills the number of HARQ feedback that UE1 is able and / or allowed to send in the HARQ feedback opportunity.

[0147] As another example, a parameter of the distance between UE1 and the UE that sends the multiple sidelink communications may indicate that UE1 is to identify or select HARQ feedback associated with sidelink communications associated with UEs whose distances from UE1 satisfy a distance threshold or do not satisfy a distance threshold. In some aspects, UE1 may determine the distance between UE1 and the UE that sends the multiple sidelink communications based at least in part on a corresponding RTT and / or another type of distance measurement associated with the UE.

[0148] In some aspects, UE1 may identify a subset of HARQ feedback based at least in part on individual signal measurements (e.g., signal strength, RSRP, RSSI, RSRP, CQI, etc.) associated with UEs that transmit multiple sidelink communications. For example, UE1 may determine that a first signal measurement associated with a first UE that transmits a first sidelink communication is larger relative to a second signal measurement associated with a second UE that transmits a second sidelink communication, and may identify or select HARQ feedback for the first sidelink communication to be included in the HARQ feedback subset based at least in part on the first signal measurement being larger relative to the second signal measurement. As another example, UE1 may determine that a first signal measurement associated with a first UE that transmits a first sidelink communication is smaller relative to a second signal measurement associated with a second UE that transmits a second sidelink communication, and may identify or select HARQ feedback for the first sidelink communication to be included in the HARQ feedback subset based at least in part on the first signal measurement being smaller relative to the second signal measurement.

[0149] As another example, parameters for one or more signal measurements associated with a UE that transmits multiple sidelink communications may indicate that UE1 will start with HARQ feedback for sidelink communications associated with the UE having the largest signal measurement, and will identify or select HARQ feedback associated with sidelink communications associated with UEs whose signal measurements gradually decrease until the HARQ feedback subset fills the number of HARQ feedback that UE1 is able and / or allowed to send in a HARQ feedback opportunity. As another example, parameters for one or more signal measurements associated with a UE that transmits multiple sidelink communications may indicate that UE1 will start with HARQ feedback for sidelink communications associated with the UE having the lowest (e.g., weakest) signal measurement, and will identify or select HARQ feedback associated with sidelink communications associated with UEs whose signal measurements gradually increase until the HARQ feedback subset fills the number of HARQ feedback that UE1 is able and / or allowed to send in a HARQ feedback opportunity.

[0150] As another example, parameters for one or more signal measurements associated with a UE sending multiple sidelink communications may indicate that UE1 will identify or select HARQ feedback associated with sidelink communications associated with a UE having signal measurements that satisfy a signal measurement threshold or that do not satisfy a signal measurement threshold.

[0151] In some aspects, UE1 may use various techniques to identify a HARQ feedback subset based at least in part on individual transmission modes associated with multiple sidelink communications. For example, a parameter for a transmission mode associated with multiple sidelink communications may specify or indicate that UE1 will identify or select HARQ feedback associated with a sidelink communication sent in a specific transmission mode or in a transmission mode in one or more specific transmission modes. The transmission mode may include a unicast transmission mode, a groupcast transmission mode, a multicast transmission mode, a broadcast transmission mode, and the like. As another example, a parameter for a transmission mode associated with multiple sidelink communications may specify or indicate a hierarchy of transmission modes (e.g., unicast>groupcast>multicast>broadcast, and / or another hierarchy), and UE1 may identify or select HARQ feedback associated with the sidelink communication by traversing the hierarchy downward until the HARQ feedback subset fills the number of HARQ feedbacks that UE1 is able and / or allowed to send in the HARQ feedback opportunity.

[0152] In some aspects, UE1 may use various techniques to identify a subset of HARQ feedbacks based at least in part on the frequency domain locations (e.g., subcarriers, subcarrier sets, etc.) of multiple HARQ feedbacks in a HARQ feedback opportunity. For example, a parameter for the frequency domain locations of multiple HARQ feedbacks may specify or indicate that UE1 is to identify or select HARQ feedbacks such that subsets of HARQ feedbacks are grouped together in a HARQ feedback opportunity, and / or such that the subsets of HARQ feedbacks result in a minimum number of HARQ feedback clusters or groups in a HARQ feedback opportunity.

[0153] Figure 4E An example of parameters for frequency domain locations of multiple HARQ feedbacks is shown. Figure 4E As shown, UE1 has identified or selected HARQ feedback to be sent in subcarrier set 1 and subcarrier set 3 in the HARQ feedback opportunity. As described above, the parameters for the frequency domain positions of multiple HARQ feedbacks can indicate that UE1 will identify or select HARQ feedback so that HARQ feedback subsets are grouped together in the HARQ feedback opportunity, and / or so that the HARQ feedback subsets result in the minimum number of HARQ feedback clusters or groups in the HARQ feedback opportunity. Therefore, for the parameters for the frequency domain positions of multiple HARQ feedbacks, UE1 can determine that the HARQ feedback to be sent in subcarrier set 2 is the highest priority because subcarrier set 1 to subcarrier set 3 are continuous and / or consecutive and result in a single HARQ feedback group or cluster in the HARQ feedback opportunity. UE1 may determine that the HARQ feedback to be sent in subcarrier set 4 is the second highest priority because subcarriers 3 and 4 are consecutive and / or contiguous and result in two HARQ feedback groups or clusters in the HARQ feedback opportunity (e.g., subcarrier set 1 is one group or cluster, and subcarrier set 3 and subcarrier set 4 are another group or cluster). UE1 may determine that the HARQ feedback to be sent in subcarrier set 5 and the HARQ feedback to be sent in subcarrier set 6 have the same priority and are the lowest priority because subcarrier set 5 and subcarrier set 6 result in three HARQ feedback groups or clusters in the HARQ feedback opportunity.

[0154] In some aspects, the UE1 may identify the HARQ feedback subset based at least in part on the above single parameter, or based on a parameter combination of the above one or more parameters. In various aspects where the UE1 identifies the HARQ feedback subset based at least in part on a parameter combination of one or more parameters, the HARQ configuration (and / or another configuration) may indicate a hierarchy for applying the one or more parameters.

[0155] For example, the hierarchy may indicate that UE1 first applies a priority parameter associated with multiple sidelink communications and secondly applies a parameter of a distance between UE1 and the UE that sends the multiple sidelink communications. In this case, if UE1 applies the parameter of a priority associated with multiple sidelink communications and determines that the HARQ feedback subset is still not suitable for the number of HARQ feedbacks that UE1 is able and / or allowed to send in the HARQ feedback opportunity, UE1 may apply the parameter of a distance between UE1 and the UE that sends the multiple sidelink communications to identify or select HARQ feedback between sidelink communications of the same priority.

[0156] As another example, the hierarchy may indicate that UE1 first applies parameters of priorities associated with multiple sidelink communications and secondly applies parameters of one or more signal measurements associated with the UE sending the multiple sidelink communications. In this case, if UE1 applies parameters of priorities associated with multiple sidelink communications and determines that the HARQ feedback subset is still not suitable for the number of HARQ feedbacks that UE1 is able and / or allowed to send in the HARQ feedback opportunity, UE1 may apply parameters of one or more signal measurements associated with the UE sending the multiple sidelink communications to identify or select HARQ feedback between sidelink communications of the same priority.

[0157] As another example, the hierarchy may instruct UE1 to first apply parameters of priorities associated with multiple sidelink communications and secondly apply parameters of transmission modes associated with multiple sidelink communications. In this case, if UE1 applies parameters of priorities associated with multiple sidelink communications and determines that the HARQ feedback subset is still not suitable for the number of HARQ feedbacks that UE1 is able and / or allowed to send in the HARQ feedback opportunity, UE1 may apply parameters of the transmission mode associated with multiple sidelink communications to identify or select HARQ feedback between sidelink communications of the same priority.

[0158] As another example, the hierarchy may instruct UE1 to first apply a parameter of a priority associated with multiple sidelink communications and secondly apply a parameter of a frequency domain location of multiple HARQ feedbacks. In this case, if UE1 applies a parameter of a priority associated with multiple sidelink communications and determines that the subset of HARQ feedbacks is still not suitable for the number of HARQ feedbacks that UE1 is able and / or allowed to send in a HARQ feedback opportunity, UE1 may apply a parameter of a frequency domain location of multiple HARQ feedbacks to identify or select HARQ feedbacks between sidelink communications of the same priority.

[0159] As another example, the hierarchy may instruct UE1 to first apply parameters of a transmission mode associated with multiple sidelink communications and secondly apply parameters of a priority associated with the multiple sidelink communications. In this case, if UE1 applies parameters of a transmission mode associated with multiple sidelink communications and determines that a subset of HARQ feedback is still not suitable for the number of HARQ feedbacks that UE1 is able and / or allowed to send in a HARQ feedback opportunity, UE1 may apply parameters of a priority associated with multiple sidelink communications to identify or select HARQ feedback between sidelink communications of the same transmission mode. A similar hierarchy is described in which parameters of a transmission mode associated with multiple sidelink communications are first applied and, after applying the parameters of the transmission mode associated with multiple sidelink communications, one or more of parameters of a priority associated with multiple sidelink communications, parameters of one or more signal measurements associated with the UE sending the multiple sidelink communications, or parameters of a distance between UE1 and the UE sending the multiple sidelink communications are applied.

[0160] The hierarchical structures for applying one or more parameters described above are examples, and other examples of hierarchical structures for applying one or more parameters (and / or other parameters) may be used to identify or select a HARQ feedback subset from multiple HARQ feedbacks.

[0161] like Figure 4F As shown, and by reference numeral 410, UE1 may send at least a HARQ feedback subset on a sidelink using one or more subcarrier sets of HARQ feedback opportunities associated with a sidelink communication corresponding to the HARQ feedback subset. For example, UE1 may send HARQ feedback for a first sidelink communication in a first subcarrier set identified for a first sidelink communication, may send HARQ feedback for a second sidelink communication in a second subcarrier set identified for a second sidelink communication, and so on. The UE may send a HARQ feedback subset in one or more HARQ feedback communications to UE2 and / or other UEs that send sidelink communications corresponding to the HARQ feedback subset. In some aspects, UE1 may send HARQ feedback communications on a feedback channel such as a physical sidelink feedback channel (PSFCH) and / or another type of channel. In some aspects, the transmission of HARQ feedback for a sidelink communication may be considered to be a feedback channel separate from HARQ feedback for other sidelink communications. In some aspects, the collective transmission of HARQ feedback for one or more sidelink communications may be considered to be a feedback channel.

[0162] In this way, UE1 can receive multiple sidelink communications on the sidelink from one or more other UEs (e.g., UE2 and / or other UEs). If UE1 determines that UE1 is unable and / or not allowed to send HARQ feedback for all sidelink communications in the HARQ feedback opportunity, UE1 can use the techniques described herein to identify a subset of HARQ feedback to be sent in the HARQ feedback opportunity. In this way, UE1 can multiplex HARQ feedback in the HARQ feedback opportunity, can identify a subset of HARQ feedback to be multiplexed in the HARQ feedback opportunity, and so on.

[0163] As mentioned above, providing Figure 4A-4F As one or more examples. Other examples can be related to Figure 4A-4F Different than described.

[0164] Figure 5 is a diagram illustrating an example process 500, performed, for example, by a UE, in accordance with aspects of the present disclosure. Example process 500 is an example of a UE (eg, UE 120) performing operations associated with techniques for sending sidelink HARQ feedback.

[0165] like Figure 5 As shown, in some aspects, process 500 may include determining multiple HARQ feedbacks for multiple sidelink communications (block 510). For example, the UE (e.g., using receive processor 258, transmit processor 264, controller / processor 280, memory 282, etc.) may determine multiple HARQ feedbacks for multiple sidelink communications, as described above.

[0166] like Figure 5 As further shown in FIG. 5 , in some aspects, process 500 may include identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks based at least in part on one or more parameters (block 520). For example, the UE (e.g., using receive processor 258, transmit processor 264, controller / processor 280, memory 282, etc.) may identify at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks based at least in part on one or more parameters, as described above.

[0167] like Figure 5 As further shown in FIG. 5 , in some aspects, process 500 may include sending at least a subset of the HARQ feedback on a sidelink in a HARQ feedback opportunity (block 530). For example, the UE (e.g., using receive processor 258, transmit processor 264, controller / processor 280, memory 282, etc.) may send at least a subset of the HARQ feedback on a sidelink in a HARQ feedback opportunity, as described above.

[0168] Process 500 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in conjunction with one or more other processes described elsewhere herein.

[0169] In a first aspect, identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks comprises identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks based at least in part on at least one of: determining that the UE cannot send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, determining that the UE is not allowed to send all of the plurality of HARQ feedbacks in a HARQ feedback opportunity, detecting a conflict between two or more of the plurality of sidelink communications, or detecting a HARQ feedback conflict in a HARQ feedback opportunity. In a second aspect, either alone or in combination with the first aspect, each of the plurality of HARQ feedbacks comprises a NACK associated with a respective one of the plurality of sidelink communications.

[0170] In a third aspect, either alone or in combination with one or more of the first and second aspects, the HARQ feedback of the multiple HARQ feedbacks includes a NACK or ACK associated with each of the multiple sidelink communications. In a fourth aspect, either alone or in combination with one or more of the first to third aspects, the process 500 further includes identifying a HARQ feedback opportunity from a plurality of periodic HARQ feedback opportunities based at least in part on the time domain resource locations of the multiple sidelink communications and the HARQ feedback delay parameter. In a fifth aspect, either alone or in combination with one or more of the first to fourth aspects, the process 500 further includes, for the multiple HARQ feedbacks, identifying each subcarrier set in the HARQ feedback opportunity based at least in part on each subchannel of the sidelink associated with the multiple sidelink communications.

[0171] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, the one or more parameters include at least one of the following: a priority associated with a plurality of sidelink communications, a distance between a UE and one or more other UEs, one or more signal measurements associated with one or more UEs, a frequency domain location of a plurality of HARQ feedbacks, or a transmission mode associated with a plurality of sidelink communications. In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, the one or more parameters include a priority associated with a plurality of sidelink communications, a priority associated with a first sidelink communication in the plurality of sidelink communications being higher than a priority associated with a second sidelink communication in the plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks from the plurality of HARQ feedbacks includes identifying the first HARQ feedback based at least in part on determining that the priority associated with the first sidelink communication is higher than a priority associated with the second sidelink communication.

[0172] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, a priority associated with the first sidelink communication is indicated in an SCI associated with the first sidelink communication. In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, one or more parameters include priorities associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, wherein the priority associated with the first sidelink communication in the multiple sidelink communications and the priority associated with the second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE in the one or more other UEs is shorter than the distance between the UE and a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE.

[0173] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0174] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the one or more parameters include priorities associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater relative to a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

[0175] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0176] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the one or more parameters include priorities associated with a plurality of sidelink communications, and transmission modes associated with the plurality of sidelink communications, wherein the priority associated with a first sidelink communication in the plurality of sidelink communications and the priority associated with a second sidelink communication in the plurality of sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a determination that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority. In a sixteenth aspect, alone or in combination with one or more of the first to fifteenth aspects, the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication include at least one of a unicast transmission mode, a groupcast transmission mode, a multicast transmission mode, or a broadcast transmission mode.

[0177] In a seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, one or more parameters include priorities associated with multiple sidelink communications, and frequency domain locations of multiple HARQ feedbacks, wherein the priority associated with a first sidelink communication in the multiple sidelink communications and the priority associated with a second sidelink communication in the multiple sidelink communications are the same priority, and identifying at least a subset of HARQ feedbacks from the multiple HARQ feedbacks includes determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in the HARQ feedback opportunity based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the first HARQ feedback or the second HARQ feedback minimizes the number of HARQ feedback clusters in the HARQ feedback opportunity.

[0178] In an eighteenth aspect, alone or in combination with one or more of the first to seventeenth aspects, the one or more parameters include a transmission mode associated with a plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback from a plurality of HARQ feedbacks or identifying a second HARQ feedback from a plurality of HARQ feedbacks based at least in part on a transmission mode associated with a first sidelink communication associated with a first HARQ feedback in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication associated with a second HARQ feedback in the plurality of sidelink communications.

[0179] In a nineteenth aspect, alone or in combination with one or more of the first to eighteenth aspects, one or more parameters include a transmission mode associated with a plurality of sidelink communications, and a priority associated with the plurality of sidelink communications, a transmission mode associated with a first sidelink communication in the plurality of sidelink communications and a transmission mode associated with a second sidelink communication in the plurality of sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from a plurality of HARQ feedbacks includes identifying a first HARQ feedback or a second HARQ feedback based at least in part on a determination that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode.

[0180] In the twentieth aspect, alone or in combination with one or more of the first to nineteenth aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and a distance between the UE and one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether the distance between the UE and a first other UE among the one or more other UEs is shorter relative to the distance between the UE and a second other UE among the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

[0181] In the twenty-first aspect, alone or in combination with one or more of the first to twentieth aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE. In the twenty-second aspect, alone or in combination with one or more of the first to twenty-first aspects, determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE.

[0182] In the twenty-third aspect, alone or in combination with one or more of the first to twenty-second aspects, the one or more parameters include a transmission mode associated with multiple sidelink communications, and one or more measurements associated with one or more other UEs, the transmission mode associated with a first sidelink communication in the multiple sidelink communications and the transmission mode associated with a second sidelink communication in the multiple sidelink communications are the same transmission mode, and identifying at least a subset of HARQ feedbacks from multiple HARQ feedbacks includes determining whether a signal strength measurement associated with a first other UE in the one or more other UEs is greater than a signal strength measurement associated with a second other UE in the one or more other UEs based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, and identifying the first HARQ feedback or the second HARQ feedback based at least in part on determining whether the signal strength measurement associated with the first other UE is greater than the signal strength measurement associated with the second other UE.

[0183] In a twenty-fourth aspect, alone or in combination with one or more of the first to twenty-third aspects, determining whether a signal strength measurement associated with a first other UE is greater relative to a signal strength measurement associated with a second other UE includes determining that the signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the first HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE. In a twenty-fifth aspect, alone or in combination with one or more of the first to twenty-fourth aspects, determining whether a signal strength measurement associated with the first other UE is greater relative to a signal strength measurement associated with the second other UE includes determining that the signal strength measurement associated with the first other UE is not greater relative to a signal strength measurement associated with the second other UE, and identifying the first HARQ feedback or the second HARQ feedback includes identifying the second HARQ feedback based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

[0184] In aspect twenty-six, alone or in combination with one or more of aspects one to twenty-fifth, one or more parameters include priorities associated with a plurality of sidelink communications, and the respective priorities associated with each of the plurality of sidelink communications are indicated in a respective SCI associated with each of the plurality of sidelink communications. In aspect twenty-seven, alone or in combination with one or more of aspects one to twenty-six, one or more parameters include respective priorities associated with each of the plurality of sidelink communications, and identifying at least a subset of HARQ feedbacks includes: for at least the subset of HARQ feedbacks, identifying a first sidelink communication having the highest priority among the plurality of sidelink communications; and for at least the subset of HARQ feedbacks, identifying, in order of decreasing priority, HARQ feedbacks associated with one or more second sidelink communications among the plurality of sidelink communications until at least the subset of HARQ feedbacks fills the number of HARQ feedbacks that the UE can send in a HARQ feedback opportunity.

[0185] although Figure 5 Example blocks of process 500 are shown, but in some aspects process 500 may include Figure 5 Those boxes depicted in the process 500 may be more boxes, fewer boxes, different blocks, or boxes in a different arrangement. Additionally or alternatively, two or more boxes of the process 500 may be performed in parallel.

[0186] Figure 66 is a conceptual data flow diagram 600 illustrating the data flow between different modules / components / components in an example apparatus 602. The apparatus 602 may be a UE (e.g., UE 120). In some aspects, the apparatus 602 includes a receiving component 604, a determining component 606, an identifying component 608, and a sending component 610.

[0187] The receiving component 604 can receive a plurality of sidelink communications 612 from one or more UEs 616 (e.g., UE 120). For example, the receiving component 604 can receive the sidelink communication 612 on a sidelink. In some aspects, the receiving component 604 can include an antenna (e.g., antenna 252), a receive processor (e.g., receive processor 258), a controller / processor (e.g., controller / processor 280), a transceiver, a receiver, etc.

[0188] The determining component 606 can determine HARQ feedback for the sidelink communication 612. For example, the determining component 606 can determine whether to send an ACK or a NACK for each sidelink communication 612. In some aspects, the determining component 606 can include a processor (e.g., the controller / processor 280, the receive processor 258, and / or the like).

[0189] The identification component 608 may identify at least a subset of HARQ feedbacks from the plurality of HARQ feedbacks based at least in part on one or more parameters. For example, the identification component 608 may identify at least a subset of HARQ feedbacks based at least in part on determining (and / or determining by another component of the device 602) that the device 602 cannot send all of the plurality of HARQ feedbacks in the HARQ feedback opportunity, determining that the device 602 is not allowed to send all of the plurality of HARQ feedbacks in the HARQ feedback opportunity, detecting a conflict between two or more sidelink communications 612, detecting a HARQ feedback conflict in a HARQ feedback opportunity, and the like. In some aspects, the one or more parameters may include, for example, a priority associated with each sidelink communication 612, a distance between the device 602 and the UE 616, one or more signal measurements associated with the UE 616, a frequency domain location of the plurality of HARQ feedbacks, a transmission mode associated with the sidelink communication 612, and the like. In some aspects, the identification component 608 may include a processor (e.g., the controller / processor 280, the receive processor 258, and / or the like).

[0190] Transmitting component 610 may transmit at least a subset of the HARQ feedback in a HARQ feedback opportunity and on a sidelink to at least one of UEs 616. For example, transmitting component 610 may transmit at least a subset of the HARQ feedback in one or more HARQ feedback communications 614. In some aspects, transmitting component 610 may include an antenna (e.g., antenna 252), a transmit processor (e.g., transmit processor 264), a controller / processor (e.g., controller / processor 280), a transceiver, a transmitter, etc.

[0191] The device 602 may include Figure 5 etc. The additional components of each box of the algorithm executed in the aforementioned process 500. Figure 5 Each block in the aforementioned process 500 of the present invention may be performed by a component, and the apparatus may include one or more of these components. These components may be one or more hardware components, specifically configured to execute a process / algorithm, the process / algorithm being implemented by a processor configured to execute the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0192] Figure 6 The number and arrangement of components shown in the figure are provided as examples. In practice, there may be additional components, fewer components, different components, or different components. Figure 6 Components with different arrangements of components shown. In addition, Figure 6 Two or more components shown in may be implemented in a single component, or Figure 6 The single component shown in can be implemented as multiple distributed components. Additionally or alternatively, Figure 6 The component collection (e.g., one or more components) shown may perform the operations described as being performed by Figure 6 Another component shown may be a collection of components that perform one or more functions.

[0193] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of these aspects.

[0194] Further disclosure is included in the appendices. The appendices are provided as examples only and are considered part of the specification. Definitions, illustrations, or other descriptions in the appendices do not supersede or override similar information included in the detailed description or drawings. Furthermore, definitions, illustrations, or other descriptions in the detailed description or drawings do not supersede or override similar information included in the appendices. Furthermore, the appendices are not intended to limit the possible aspects of the disclosure.

[0195] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, and / or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, and / or a combination of hardware and software.

[0196] As used herein, satisfying a threshold may refer to a value greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0197] It will be apparent that the systems and / or methods described herein may be implemented in various forms of hardware, firmware, and / or combinations of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit these aspects. Thus, the operation and behavior of the systems and / or methods are described herein without reference to specific software code—it should be understood that software and hardware may be designed to implement the systems and / or methods based, at least in part, on the description herein.

[0198] Even though specific combinations of features are recited in the claims and / or in the specification, these combinations are not intended to limit the disclosure of the various aspects. In fact, many of these features can be combined in ways that are not specifically recited in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of the various aspects includes each dependent claim in combination with each other claim in the claim set. A phrase referring to "at least one" in a list of items refers to any combination of these items, including single members. For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiples of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc or any other order of a, b, and c).

[0199] Unless explicitly stated, any element, act, or instruction used herein should not be construed as critical or essential. In addition, as used herein, the articles "a" and "an" are intended to include one or more items and can be used interchangeably with "one or more." In addition, as used herein, the terms "set" and "group" are intended to include one or more items (e.g., related items, unrelated items, combinations of related and unrelated items, etc.) and can be used interchangeably with "one or more." Figure 1 In the case of a single item, the phrase "only one" or similar language is used. In addition, as used herein, the terms "has," "have," "having," etc. are intended to be open-ended terms. In addition, unless expressly stated otherwise, the phrase "based on" means "based at least in part on."

Claims

1. A method of wireless communication performed by a user equipment (UE), comprising: determining a plurality of hybrid automatic repeat request (HARQ) feedbacks for a plurality of sidelink communications; identifying, for at least one subset of HARQ feedbacks from the plurality of HARQ feedbacks and based at least in part on one or more parameters, HARQ feedbacks associated with one or more sidelink communications of the plurality of sidelink communications, wherein the number of HARQ feedbacks is greater than one HARQ feedback; and The at least one HARQ feedback subset is sent on a sidelink in the HARQ feedback opportunity.

2. The method according to claim 1, wherein: The one or more parameters include at least one of the following: priorities associated with the plurality of sidelink communications, The distance between the UE and one or more other UEs, one or more signal measurements associated with the one or more UEs, The frequency domain positions of the multiple HARQ feedbacks, or A transmission mode associated with the plurality of sidelink communications.

3. The method according to claim 1, wherein: The one or more parameters include: priorities associated with the plurality of sidelink communications; wherein a priority associated with a first sidelink communication of the plurality of sidelink communications is higher than a priority associated with a second sidelink communication of the plurality of sidelink communications, wherein the first sidelink communication is associated with a first HARQ feedback of the plurality of HARQ feedbacks, and wherein the second sidelink communication is associated with a second HARQ feedback among the plurality of HARQ feedbacks; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: The first HARQ feedback is identified based at least in part on determining that the priority associated with the first sidelink communication is higher relative to the priority associated with the second sidelink communication.

4. The method according to claim 1, wherein: The one or more parameters include priorities associated with the plurality of sidelink communications; and wherein a respective priority level associated with each of the plurality of sidelink communications is indicated in respective sidelink control information (SCI) associated with each of the plurality of sidelink communications.

5. The method according to claim 1, wherein: The one or more parameters include a respective priority level associated with each of the plurality of sidelink communications; as well as The identifying of the at least one HARQ feedback subset includes: for the at least one HARQ feedback subset, identifying HARQ feedback associated with a first sidelink communication having a highest priority among the plurality of sidelink communications; and For the at least one HARQ feedback subset, HARQ feedback associated with one or more second sidelink communications among the multiple sidelink communications are identified in order of decreasing priority until the at least one HARQ feedback subset fills the number of HARQ feedbacks that the UE can send in the HARQ feedback opportunity.

6. The method according to claim 1, wherein: Identifying the HARQ feedback associated with one or more sidelink communications comprises: and identifying the HARQ feedback associated with one or more sidelink communications based at least in part on at least one of: determining that the UE is unable to send all of the plurality of HARQ feedbacks at the HARQ feedback timing, determining not to allow the UE to send all of the multiple HARQ feedbacks in the HARQ feedback opportunity, detecting a collision between two or more of the plurality of sidelink communications, or A HARQ feedback conflict in the HARQ feedback opportunity is detected.

7. The method according to claim 1, wherein: The HARQ feedback of the multiple HARQ feedbacks includes: A negative acknowledgement (NACK) or an acknowledgement (ACK) associated with a respective sidelink communication of the plurality of sidelink communications.

8. The method according to claim 1, further comprising: and identifying the HARQ feedback opportunity from a plurality of periodic HARQ feedback opportunities based at least in part on: time domain resource locations of the plurality of sidelink communications, and HARQ feedback delay parameter.

9. The method according to claim 8, further comprising: For the plurality of HARQ feedbacks, respective sets of subcarriers in the HARQ feedback opportunities are identified based at least in part on respective subchannels of the sidelink associated with the plurality of sidelink communications.

10. The method according to claim 1, wherein: The one or more parameters include: priorities associated with the plurality of sidelink communications, and The distance between the UE and one or more other UEs; wherein a priority associated with a first sidelink communication of the plurality of sidelink communications and a priority associated with a second sidelink communication of the plurality of sidelink communications are the same priority, wherein the first sidelink communication is associated with a first HARQ feedback of the plurality of HARQ feedbacks, and wherein the second sidelink communication is associated with a second HARQ feedback among the plurality of HARQ feedbacks; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: determining, based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, whether a distance between the UE and a first other UE of the one or more other UEs is shorter than a distance between the UE and a second other UE of the one or more other UEs; and The first HARQ feedback or the second HARQ feedback is identified based at least in part on determining whether the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

11. The method according to claim 10, wherein: Determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes: determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE; and The identifying the first HARQ feedback or the second HARQ feedback includes: The first HARQ feedback is identified based at least in part on determining that the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

12. The method according to claim 10, wherein: Determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes: determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE; and The identifying the first HARQ feedback or the second HARQ feedback includes: The second HARQ feedback is identified based at least in part on determining that the distance between the UE and the first other UE is not shorter relative to the distance between the UE and the second other UE.

13. The method according to claim 1, wherein: The one or more parameters include: priorities associated with the plurality of sidelink communications, and one or more measurements associated with one or more other UEs; wherein a priority associated with a first sidelink communication of the plurality of sidelink communications and a priority associated with a second sidelink communication of the plurality of sidelink communications are the same priority, wherein the first sidelink communication is associated with a first HARQ feedback of the plurality of HARQ feedbacks, and wherein the second sidelink communication is associated with a second HARQ feedback among the plurality of HARQ feedbacks; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: determining, based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority, whether a signal strength measurement associated with a first other UE of the one or more other UEs is greater relative to a signal strength measurement associated with a second other UE of the one or more other UEs; and The first HARQ feedback or the second HARQ feedback is identified based at least in part on determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

14. The method according to claim 13, wherein: Determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE includes: determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE; and The identifying the first HARQ feedback or the second HARQ feedback includes: The first HARQ feedback is identified based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

15. The method according to claim 13, wherein: Determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE includes: determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE; and The identifying the first HARQ feedback or the second HARQ feedback includes: The second HARQ feedback is identified based at least in part on determining that the signal strength measurement associated with the first other UE is not greater relative to the signal strength measurement associated with the second other UE.

16. The method according to claim 1, wherein: The one or more parameters include: priorities associated with the plurality of sidelink communications, and a transmission mode associated with the plurality of sidelink communications; wherein a priority associated with a first sidelink communication of the plurality of sidelink communications and a priority associated with a second sidelink communication of the plurality of sidelink communications are the same priority, wherein the first sidelink communication is associated with a first HARQ feedback of the plurality of HARQ feedbacks, and wherein the second sidelink communication is associated with a second HARQ feedback among the plurality of HARQ feedbacks; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: Identifying the first HARQ feedback or the second HARQ feedback based at least in part on a transmission mode associated with the first sidelink communication and a transmission mode associated with the second sidelink communication based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority.

17. The method according to claim 1, wherein: The one or more parameters include: priorities associated with the plurality of sidelink communications, and The frequency domain positions of the multiple HARQ feedbacks; wherein a priority associated with a first sidelink communication of the plurality of sidelink communications and a priority associated with a second sidelink communication of the plurality of sidelink communications are the same priority, wherein the first sidelink communication is associated with a first HARQ feedback of the plurality of HARQ feedbacks, and wherein the second sidelink communication is associated with a second HARQ feedback among the plurality of HARQ feedbacks; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: determining whether the first HARQ feedback or the second HARQ feedback minimizes a number of HARQ feedback clusters in the HARQ feedback opportunities based at least in part on determining that the priority associated with the first sidelink communication and the priority associated with the second sidelink communication are the same priority; and The first HARQ feedback or the second HARQ feedback is identified based at least in part on determining whether the first HARQ feedback or the second HARQ feedback minimizes a number of HARQ feedback clusters in the HARQ feedback opportunity.

18. The method according to claim 1, wherein: The one or more parameters include: transmission modes associated with the plurality of sidelink communications; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: and identifying a first HARQ feedback from the plurality of HARQ feedbacks or identifying a second HARQ feedback from the plurality of HARQ feedbacks based at least in part on: a transmission mode associated with a first sidelink communication of the plurality of sidelink communications associated with the first HARQ feedback, and A transmission mode associated with a second sidelink communication of the plurality of sidelink communications associated with the second HARQ feedback.

19. The method according to claim 1, wherein: The one or more parameters include: transmission modes associated with the plurality of sidelink communications, and priorities associated with the plurality of sidelink communications; wherein a transmission mode associated with a first sidelink communication of the plurality of sidelink communications and a transmission mode associated with a second sidelink communication of the plurality of sidelink communications are the same transmission mode, wherein the first sidelink communication is associated with a first HARQ feedback of the plurality of HARQ feedbacks, and wherein the second sidelink communication is associated with a second HARQ feedback among the plurality of HARQ feedbacks; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: Identifying the first HARQ feedback or the second HARQ feedback based at least in part on a priority associated with the first sidelink communication and a priority associated with the second sidelink communication based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode.

20. The method according to claim 1, wherein: The one or more parameters include: a transmission mode associated with the plurality of sidelink communications, and The distance between the UE and one or more other UEs; wherein a transmission mode associated with a first sidelink communication of the plurality of sidelink communications and a transmission mode associated with a second sidelink communication of the plurality of sidelink communications are the same transmission mode, wherein the first sidelink communication is associated with a first HARQ feedback of the plurality of HARQ feedbacks, and wherein the second sidelink communication is associated with a second HARQ feedback among the plurality of HARQ feedbacks; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: determining, based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, whether a distance between the UE and a first other UE of the one or more other UEs is shorter than a distance between the UE and a second other UE of the one or more other UEs; and The first HARQ feedback or the second HARQ feedback is identified based at least in part on determining whether the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

21. The method according to claim 20, wherein: Determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes: determining that the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE; and The identifying the first HARQ feedback or the second HARQ feedback includes: The first HARQ feedback is identified based at least in part on determining that the distance between the UE and the first other UE is shorter relative to the distance between the UE and the second other UE.

22. The method according to claim 20, wherein: Determining whether the distance between the UE and the first other UE is shorter than the distance between the UE and the second other UE includes: determining that the distance between the UE and the first other UE is not shorter than the distance between the UE and the second other UE; and The identifying the first HARQ feedback or the second HARQ feedback includes: The second HARQ feedback is identified based at least in part on determining that the distance between the UE and the first other UE is not shorter relative to the distance between the UE and the second other UE.

23. The method according to claim 1, wherein: The one or more parameters include: a transmission mode associated with the plurality of sidelink communications, and one or more measurements associated with one or more other UEs; wherein a transmission mode associated with a first sidelink communication of the plurality of sidelink communications and a transmission mode associated with a second sidelink communication of the plurality of sidelink communications are the same transmission mode, wherein the first sidelink communication is associated with a first HARQ feedback of the plurality of HARQ feedbacks, and wherein the second sidelink communication is associated with a second HARQ feedback among the plurality of HARQ feedbacks; and Wherein identifying the HARQ feedback associated with one or more sidelink communications comprises: determining, based at least in part on determining that the transmission mode associated with the first sidelink communication and the transmission mode associated with the second sidelink communication are the same transmission mode, whether a signal strength measurement associated with a first other UE of the one or more other UEs is greater relative to a signal strength measurement associated with a second other UE of the one or more other UEs; and The first HARQ feedback or the second HARQ feedback is identified based at least in part on determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

24. The method according to claim 23, wherein: Determining whether the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE includes: determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE; and The identifying the first HARQ feedback or the second HARQ feedback includes: The first HARQ feedback is identified based at least in part on determining that the signal strength measurement associated with the first other UE is greater relative to the signal strength measurement associated with the second other UE.

25. A user equipment (UE) for wireless communication, comprising: Memory; as well as one or more processors operatively coupled to the memory, configured to: determining a plurality of hybrid automatic repeat request (HARQ) feedbacks for a plurality of sidelink communications; identifying, for at least one subset of HARQ feedbacks from the plurality of HARQ feedbacks and based at least in part on one or more parameters, HARQ feedbacks associated with one or more sidelink communications of the plurality of sidelink communications, wherein the number of HARQ feedbacks is greater than one HARQ feedback; and The at least one HARQ feedback subset is sent on a sidelink in the HARQ feedback opportunity.

26. The UE according to claim 25, wherein: The one or more parameters include priorities associated with the plurality of sidelink communications.

27. The UE according to claim 25, wherein: A respective priority level associated with each of the plurality of sidelink communications is indicated in respective sidelink control information (SCI) associated with each of the plurality of sidelink communications.

28. The UE of claim 25, wherein the one or more processors, when identifying for the at least one HARQ feedback subset, are configured to: for the at least one HARQ feedback subset, identifying HARQ feedback associated with a first sidelink communication having a highest priority among the plurality of sidelink communications; and For the at least one HARQ feedback subset, HARQ feedback associated with one or more second sidelink communications among the one or more sidelink communications are identified in order of decreasing priority until the at least one HARQ feedback subset fills the number of HARQ feedbacks that the UE can send in the HARQ feedback opportunity.

29. A non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising: One or more instructions that, when executed by one or more processors of a user equipment (UE), cause the one or more processors to perform: determining a plurality of hybrid automatic repeat request (HARQ) feedbacks for a plurality of sidelink communications; identifying, for at least one subset of HARQ feedbacks from the plurality of HARQ feedbacks and based at least in part on one or more parameters, HARQ feedbacks associated with one or more sidelink communications of the plurality of sidelink communications, wherein the number of HARQ feedbacks is greater than one HARQ feedback; and The at least one HARQ feedback subset is sent on a sidelink in the HARQ feedback opportunity.

30. The non-transitory computer readable medium of claim 29, wherein: The one or more parameters include priorities associated with the plurality of sidelink communications.

31. An apparatus for wireless communication, comprising: means for determining a plurality of hybrid automatic repeat request (HARQ) feedbacks for a plurality of sidelink communications; means for identifying, for at least one subset of HARQ feedbacks from the plurality of HARQ feedbacks and based at least in part on one or more parameters, HARQ feedback associated with one or more sidelink communications of the plurality of sidelink communications, wherein the number of HARQ feedbacks is greater than one HARQ feedback; and Means for sending the at least one HARQ feedback subset on a sidelink in the HARQ feedback opportunity.

32. The device according to claim 31, wherein The one or more parameters include priorities associated with the plurality of sidelink communications.

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