WO2024210962A1 - Priority ordering of hybrid automatic repeat request feedback communications - Google Patents

Abstract

Wireless communications systems, apparatuses, and methods are provided. A method of wireless communication performed by a first sidelink user equipment (UE) includes receiving, from a plurality of sidelink UEs, a plurality of sidelink communications and transmitting, to one or more of the plurality of sidelink UEs based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications, wherein the priority order is based on priorities associated with the plurality of sidelink communications and priorities associated with HARQ feedback opportunities.

Description

PRIORITY ORDERING OF HYBRID AUTOMATIC REPEAT REQUEST FEEDBACK COMMUNICATIONS

CROSS-REFERENCE TO A RELATED APPLICATION

[0001] The present application claims priority to and the benefit of Greek Patent Application No. 20230100280, filed April 3, 2023, the disclosure of which is referenced herein in its entirety as if fully set forth below and for all applicable purposes.

TECHNICAL FIELD

[0002] This application relates to wireless communication systems, and more particularly, to priority ordering of hybrid automatic repeat request (HARQ) feedback communications in unlicensed spectrum.

INTRODUCTION

[0003] Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). A wireless multiple-access communications system may include a number of base stations (BSs), each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipment (UE).

[0004] To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies are advancing from the LTE technology to a next generation new radio (NR) technology. For example, NR is designed to provide a lower latency, a higher bandwidth or throughput, and a higher reliability than LTE. NR is designed to operate over a wide array of spectrum bands, for example, from low- frequency bands below about 1 gigahertz (GHz) and mid-frequency bands from about 1 GHz to about 6 GHz, to high-frequency bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrums to dynamically support high-bandwidth services. Spectrum sharing can extend the benefit of NR technologies to operating entities that may not have access to a licensed spectrum. [0005] NR may support various deployment scenarios to benefit from the various spectrums in different frequency ranges, licensed and/or unlicensed, and/or coexistence of the LTE and NR technologies. For example, NR can be deployed in a standalone NR mode over a licensed and/or an unlicensed band or in a dual connectivity mode with various combinations of NR and LTE over licensed and/or unlicensed bands.

[0006] In a wireless communication network, a BS may communicate with a UE in an uplink direction and a downlink direction. Sidelink was introduced in LTE to allow a UE to send data to another UE (e.g., from one vehicle to another vehicle) without tunneling through the BS and/or an associated core network. The LTE sidelink technology has been extended to provision for device-to-device (D2D) communications, vehicle-to-every thing (V2X) communications, and/or cellular vehicle- to-everything (C- V2X) communications. Similarly, NR may be extended to support sidelink communications, D2D communications, V2X communications, and/or C-V2X over licensed frequency bands and/or unlicensed frequency bands (e.g., shared frequency bands).

BRIEF SUMMARY OF SOME EXAMPLES

[0007] The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later.

[0008] In an aspect of the disclosure, a method of wireless communication performed by a first sidelink user equipment (UE), may include receiving, from a plurality of sidelink UEs, a plurality of sidelink communications; and transmitting, to one or more of the plurality of sidelink UEs based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications, wherein the priority order is based on: priorities associated with the plurality of sidelink communications; and priorities associated with HARQ feedback opportunities.

[0009] In an additional aspect of the disclosure, a method of wireless communication performed by a first sidelink user equipment (UE) may include receiving, from a first plurality of sidelink UEs, a first plurality of sidelink communications; transmitting, to a second plurality of sidelink UEs, a second plurality of sidelink communications; and communicating hybrid automatic repeat request (HARQ) feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications based on: priorities associated with the first plurality of sidelink communications; priorities associated with the second plurality of sidelink communications; priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications; and priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

[0010] In an additional aspect of the disclosure, a first sidelink user equipment (UE) may include a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to receive, from a plurality of sidelink UEs, a plurality of sidelink communications; and transmit, to one or more of the plurality of sidelink UEs based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications, wherein the priority order is based on: priorities associated with the plurality of sidelink communications; and priorities associated with HARQ feedback opportunities.

[0011] In an additional aspect of the disclosure, a first sidelink user equipment (UE) may include a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to receive, from a first plurality of sidelink UEs, a first plurality of sidelink communications; transmit, to a second plurality of sidelink UEs, a second plurality of sidelink communications; and communicate hybrid automatic repeat request (HARQ) feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications based on: priorities associated with the first plurality of sidelink communications; priorities associated with the second plurality of sidelink communications; priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications; and priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

[0012] Other aspects, features, and instances of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary instances of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain aspects and figures below, all instances of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more instances may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various instances of the invention discussed herein. In similar fashion, while exemplary aspects may be discussed below as device, system, or method instances it should be understood that such exemplary instances can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 illustrates a wireless communication network according to some aspects of the present disclosure.

[0014] FIG. 2 illustrates an example disaggregated base station architecture according to some aspects of the present disclosure.

[0015] FIG. 3 illustrates multiple PSFCH opportunities in a wireless communication network according to some aspects of the present disclosure.

[0016] FIGS. 4A-4D illustrate priority ordering for multiple PSFCH opportunities. [0017] FIG. 5 is a signal flow diagram for multiple PSFCH opportunities according to some aspects of the present disclosure.

[0018] FIG. 6 is a signal flow diagram for multiple PSFCH opportunities according to some aspects of the present disclosure.

[0019] FIG. 7 is a block diagram of an exemplary user equipment (UE) according to some aspects of the present disclosure.

[0020] FIG. 8 is a block diagram of an exemplary network unit according to some aspects of the present disclosure.

[0021] FIG. 9 is a flow diagram of a communication method according to some aspects of the present disclosure.

[0022] FIG. 10 is a flow diagram of a communication method according to some aspects of the present disclosure.

DETAILED DESCRIPTION

[0023] The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0024] This disclosure relates generally to wireless communications systems, also referred to as wireless communications networks. In various instances, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, 5^th Generation (5G) or new radio (NR) networks, as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably.

[0025] An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA), Institute of Electrical and Electronic Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and Global System for Mobile Communications (GSM) are part of universal mobile telecommunication system (UMTS). In particular, long term evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3^rd Generation Partnership Project” (3GPP), and cdma2000 is described in documents from an organization named “3^rd Generation Partnership Project 2” (3GPP2). These various radio technologies and standards are known or are being developed. For example, the 3^rd Generation Partnership Project (3 GPP) is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3 GPP long term evolution (LTE) is a 3GPP project which was aimed at improving the universal mobile telecommunications system (UMTS) mobile phone standard. The 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. The present disclosure is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond with shared access to wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces. [0026] In particular, 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. In order to achieve these goals, further enhancements to LTE and LTE-A are considered in addition to development of the new radio technology for 5G NR networks. The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (loTs) with an ultra-high density (e.g., -1M nodes/km2), ultra-low complexity (e.g., ~10s of bits/sec), ultra-low energy (e.g., -10+ years of battery life), and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., -99.9999% reliability), ultra-low latency (e.g., - 1 ms), and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., - 10 Tbps/km2), extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates), and deep awareness with advanced discovery and optimizations.

[0027] The 5G NR may be implemented to use optimized OFDM-based waveforms with scalable numerology and transmission time interval (TTI); having a common, flexible framework to efficiently multiplex services and features with a dynamic, low- latency time division duplex (TDD)/frequency division duplex (FDD) design; and with advanced wireless technologies, such as massive multiple input, multiple output (MIMO), robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz, for example over 5, 10, 20 MHz, and the like bandwidth (BW). For other various outdoor and small cell coverage deployments of TDD greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz BW. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160 MHz BW. Finally, for various deployments transmitting with mmWave components at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500MHz BW.

[0028] The scalable numerology of the 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TT1 may be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs to allow transmissions to start on symbol boundaries. 5G NR also contemplates a self-contained integrated subframe design with uplink/downlink scheduling information, data, and acknowledgement in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive uplink/downlink that may be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet the current traffic needs.

[0029] Various other aspects and features of the disclosure are further described below. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative and not limiting. Based on the teachings herein one of an ordinary level of skill in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. For example, a method may be implemented as part of a system, device, apparatus, and/or as instructions stored on a computer readable medium for execution on a processor or computer. Furthermore, an aspect may comprise at least one element of a claim.

[0030] The deployment of NR over an unlicensed spectrum is referred to as NR- unlicensed (NR-U). Federal Communications Commission (FCC) and European Telecommunications Standards Institute (ETSI) are working on regulating 6 GHz as a new unlicensed band for wireless communications. The addition of 6 GHz bands allows for hundreds of megahertz (MHz) of bandwidth (B W) available for unlicensed band communications. Additionally, NR-U can also be deployed over 2.4 GHz unlicensed bands, which are currently shared by various radio access technologies (RATs), such as IEEE 802.11 wireless local area network (WLAN) or WiFi and/or license assisted access (LAA). Sidelink communications may benefit from utilizing the additional bandwidth available in an unlicensed spectrum. However, channel access in a certain unlicensed spectrum may be regulated by authorities. For instance, some unlicensed bands may impose restrictions on the power spectral density (PSD) and/or minimum occupied channel bandwidth (OCB) for transmissions in the unlicensed bands. For example, the unlicensed national information infrastructure (UNII) radio band has a minimum OCB requirement of about at least 70 percent (%).

[0031] Some sidelink systems may operate over a 20 MHz bandwidth, e.g., for listen before talk (LBT) based channel accessing, in an unlicensed band. A BS may configure a sidelink resource pool over one or multiple 20 MHz LBT sub-bands for sidelink communications. A sidelink: resource pool is typically allocated with multiple frequency subchannels within a sidelink: band width part (SL-BWP) and a sidelink UE may select a sidelink resource (e.g., one or multiple subchannel) in frequency and one or multiple slots in time) from the sidelink resource pool for sidelink communication.

[0032] Deployment of communication systems, such as 5G new radio (NR) systems, may be arranged in multiple manners with various components or constituent parts. In a 5G NR system, or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element, or a network equipment, such as a base station (BS), or one or more units (or one or more components) performing base station functionality, may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB), evolved NB (eNB), NR BS, 5G NB, access point (AP), a transmit receive point (TRP), or a cell, etc.) may be implemented as an aggregated base station (also known as a standalone BS or a monolithic BS) or a disaggregated base station.

[0033] An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A disaggregated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (Rus)). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs may be implemented to communicate with one or more Rus. Each of the CU, DU and RU also can be implemented as virtual units, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0034] Base station-type operation or network design may consider aggregation characteristics of base station functionality. For example, disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Disaggregation may include distributing functionality across two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network design. The various units of the disaggregated base station, or disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit.

[0035] FIG. 1 illustrates a wireless communication network 100 according to some aspects of the present disclosure. The network 100 includes a number of base stations (BSs) 105 and other network entities. A BS 105 may be a station that communicates with UEs 115 and may also be referred to as an evolved node B (eNB), a next generation eNB (gNB), an access point, and the like. Each BS 105 may provide communication coverage for a particular geographic area. In 3 GPP, the term “cell” can refer to this particular geographic coverage area of a BS 105 and/or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0036] A BS 105 may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS or a home BS. In the example shown in FIG. 1, the BSs 105d and 105e may be regular macro BSs, while the BSs 105a-105c may be macro BSs enabled with one of three dimension (3D), full dimension (FD), or massive MIMO. The BSs 105a-105c may take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. The BS 105f may be a small cell BS which may be a home node or portable access point. A BS 105 may support one or multiple (e.g., two, three, four, and the like) cells. [0037] The network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time.

[0038] The UEs 115 are dispersed throughout the wireless network 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like. A UE 115 may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. In one aspect, a UE 115 may be a device that includes a Universal Integrated Circuit Card (UICC). In another aspect, a UE may be a device that does not include a UICC. In some aspects, the UEs 115 that do not include UICCs may also be referred to as loT devices or internet of everything (loE) devices. The UEs 115a-l 15d are examples of mobile smart phone- type devices accessing network 100. A UE 115 may also be a machine specifically configured for connected communication, including machine type communication (MTC), enhanced MTC (eMTC), narrowband loT (NB-IoT) and the like. The UEs 115e- 115h are examples of various machines configured for communication that access the network 100. The UEs 115i-l 15k are examples of vehicles equipped with wireless communication devices configured for communication that access the network 100. A UE 115 may be able to communicate with any type of the BSs, whether macro BS, small cell, or the like. In FIG. 1, a lightning bolt (e.g., communication links) indicates wireless transmissions between a UE 115 and a serving BS 105, which is a BS designated to serve the UE 115 on the downlink (DL) and/or uplink (UL), desired transmission between BSs 105, backhaul transmissions between BSs, or sidelink transmissions between UEs 115.

[0039] In operation, the BSs 105a-105c may serve the UEs 115a and 115b using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. The macro BS 105d may perform backhaul communications with the BSs 105a- 105c, as well as small cell, the BS 105f. The macro BS 105d may also transmits multicast services which are subscribed to and received by the UEs 115c and 115d. Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

[0040] The BSs 105 may also communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs 105 (e.g., which may be an example of an evolved NodeB (eNB) or an access node controller (ANC)) may interface with the core network 130 through backhaul links (e.g., SI, S2, etc.) and may perform radio configuration and scheduling for communication with the UEs 115. In various examples, the BSs 105 may communicate, either directly or indirectly (e.g., through core network), with each other over backhaul links (e.g., XI, X2, etc.), which may be wired or wireless communication links.

[0041] The network 100 may also support mission critical communications with ultrareliable and redundant links for mission critical devices, such as the UE 115e, which may be a vehicle (e.g., a car, a truck, a bus, an autonomous vehicle, an aircraft, a boat, etc.). Redundant communication links with the UE 115e may include links from the macro BSs 105d and 105e, as well as links from the small cell BS 105f. Other machine type devices, such as the UE 115f (e.g., a thermometer), the UE 115g (e.g., smart meter), and UE 115h (e.g., wearable device) may communicate through the network 100 either directly with BSs, such as the small cell BS 105f, and the macro BS 105e, or in multi-hop configurations by communicating with another user device which relays its information to the network, such as the UE 115f communicating temperature measurement information to the smart meter, the UE 115g, which is then reported to the network through the small cell BS 105f. In some aspects, the UE 115h may harvest energy from an ambient environment associated with the UE 115h. The network 100 may also provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such as vehicle-to-vehicle (V2V), vehicle-to-everything (V2X), cellular-vehicle-to-everything (C-V2X) communications between a UE 115i, 115j , or 115k and other UEs 115, and/or vehicle-to-infrastructure (V2I) communications between a UE 115i, 115j, or 115k and a BS 105.

[0042] In some implementations, the network 100 utilizes OFDM-based waveforms for communications. An OFDM-based system may partition the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, bins, or the like. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system BW. The system BW may also be partitioned into subbands. In other instances, the subcarrier spacing and/or the duration of TTIs may be scalable.

[0043] In some instances, the BSs 105 can assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RB)) for downlink (DL) and uplink (UL) transmissions in the network 100. DL refers to the transmission direction from a BS 105 to a UE 115, whereas UL refers to the transmission direction from a UE 115 to a BS 105. The communication can be in the form of radio frames. A radio frame may be divided into a plurality of subframes, for example, about 10. Each subframe can be divided into slots, for example, about 2. Each slot may be further divided into minislots. In a FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In a TDD mode, UL and DL transmissions occur at different time periods using the same frequency band. For example, a subset of the subframes (e.g., DL subframes) in a radio frame may be used for DL transmissions and another subset of the subframes (e.g., UL subframes) in the radio frame may be used for UL transmissions.

[0044] The DL subframes and the UL subframes can be further divided into several regions. For example, each DL or UL subframe may have pre-defined regions for transmissions of reference signals, control information, and data. Reference signals are predetermined signals that facilitate the communications between the BSs 105 and the UEs 115. For example, a reference signal can have a particular pilot pattern or structure, where pilot tones may span across an operational BW or frequency band, each positioned at a pre-defined time and a pre-defined frequency. For example, a BS 105 may transmit cell specific reference signals (CRSs) and/or channel state information - reference signals (CSI-RSs) to enable a UE 115 to estimate a DL channel. Similarly, a UE 115 may transmit sounding reference signals (SRSs) to enable a BS 105 to estimate a UL channel. Control information may include resource assignments and protocol controls. Data may include protocol data and/or operational data. In some instances, the BSs 105 and the UEs 115 may communicate using self-contained subframes. A self- contained subframe may include a portion for DL communication and a portion for UL communication. A self-contained subframe can be DL-centric or UL-centric. A DL- centric subframe may include a longer duration for DL communication than for UL communication. A UL-centric subframe may include a longer duration for UL communication than for UL communication.

[0045] In some instances, the network 100 may be an NR network deployed over a licensed spectrum. The BSs 105 can transmit synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)) in the network 100 to facilitate synchronization. The BSs 105 can broadcast system information associated with the network 100 (e.g., including a master information block (MIB), remaining minimum system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some instances, the BSs 105 may broadcast the PSS, the SSS, and/or the MIB in the form of synchronization signal blocks (SSBs) over a physical broadcast channel (PBCH) and may broadcast the RMSI and/or the OSI over a physical downlink shared channel (PDSCH).

[0046] In some instances, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a PSS from a BS 105. The PSS may enable synchronization of period timing and may indicate a physical layer identity value. The UE 115 may then receive an SSS. The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The SSS may also enable detection of a duplexing mode and a cyclic prefix length. The PSS and the SSS may be located in a central portion of a carrier or any suitable frequencies within the carrier.

[0047] After receiving the PSS and SSS, the UE 115 may receive a MIB. The MIB may include system information for initial network access and scheduling information for RMSI and/or OSI. After decoding the MIB, the UE 115 may receive RMSI and/or OSI. The RMSI and/or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), power control, SRS, and cell barring.

[0048] After obtaining the MIB, the RMSI and/or the OSI, the UE 115 can perform a random access procedure to establish a connection with the BS 105. For the random access procedure, the UE 115 may transmit a random access preamble and the BS 105 may respond with a random access response. Upon receiving the random access response, the UE 115 may transmit a connection request to the BS 105 and the BS 105 may respond with a connection response (e.g., contention resolution message). [0049] After establishing a connection, the UE 115 and the BS 105 can enter a normal operation stage, where operational data may be exchanged. For example, the BS 105 may schedule the UE 115 for UL and/or DL communications. The BS 105 may transmit UL and/or DL scheduling grants to the UE 115 via a PDCCH. The BS 105 may transmit a DL communication signal to the UE 115 via a PDSCH according to a DL scheduling grant. The UE 115 may transmit a UL communication signal to the BS 105 via a PUSCH and/or PUCCH according to a UL scheduling grant.

[0050] The network 100 may be designed to enable a wide range of use cases. While in some examples a network 100 may utilize monolithic base stations, there are a number of other architectures which may be used to perform aspects of the present disclosure. For example, a BS 105 may be separated into a remote radio head (RRH) and baseband unit (BBU). BBUs may be centralized into a BBU pool and connected to RRHs through low-latency and high-bandwidth transport links, such as optical transport links. BBU pools may be cloud-based resources. In some aspects, baseband processing is performed on virtualized servers running in data centers rather than being co-located with a BS 105. In another example, based station functionality may be split between a remote unit (RU), distributed unit (DU), and a central unit (CU). An RU generally performs low physical layer functions while a DU performs higher layer functions, which may include higher physical layer functions. A CU performs the higher RAN functions, such as radio resource control (RRC).

[0051] For simplicity of discussion, the present disclosure refers to methods of the present disclosure being performed by base stations, or more generally network entities, while the functionality may be performed by a variety of architectures other than a monolithic base station. In addition to disaggregated base stations, aspects of the present disclosure may also be performed by a centralized unit (CU), a distributed unit (DU), a radio unit (RU), a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC), a NonReal Time (Non-RT) RIC, integrated access and backhaul (IAB) node, a relay node, a sidelink node, etc.

[0052] In some aspects, the UE 115j may receive, from a plurality of sidelink UEs 115, a plurality of sidelink communications. The UE 115j may transmit, to one or more of the plurality of sidelink UEs 115 based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications. In some aspects, the priority order may be based on priorities associated with the plurality of sidelink communications and priorities associated with HARQ feedback opportunities.

[0053] In some aspects, the UE 115j may receive, from a first plurality of sidelink UEs 115, a first plurality of sidelink communications. The UE 115j may transmit, to a second plurality of sidelink UEs 115, a second plurality of sidelink communications and communicate hybrid automatic repeat request (HARQ) feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications. The UE 115j may communicate the HARQ feedback based on priorities associated with the first plurality of sidelink communications, priorities associated with the second plurality of sidelink communications, priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications, and priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

[0054] FIG. 2 shows a diagram illustrating an example disaggregated base station 200 architecture. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that can communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 225 via an E2 link, or a Non-Real Time (Non-RT) RIC 215 associated with a Service Management and Orchestration (SMO) Framework 205, or both). A CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an Fl interface. The DUs 230 may communicate with one or more radio units (Rus) 240 via respective fronthaul links. The Rus 240 may communicate with respective UEs 115 via one or more radio frequency (RF) access links. In some implementations, the UE 115 may be simultaneously served by multiple Rus 240.

[0055] Each of the units, i.e., the CUs 210, the DUs 230, the RUs 240, as well as the Near-RT RICs 225, the Non-RT RICs 215 and the SMO Framework 205, may include one or more interfaces or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communication interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units. Additionally, the units can include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver), configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.

[0056] In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (i.e., Central Unit - User Plane (CU-UP)), control plane functionality (i.e., Central Unit - Control Plane (CU-CP)), or a combination thereof. In some implementations, the CU 210 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the El interface when implemented in an O-RAN configuration. The CU 210 can be implemented to communicate with the DU 230, as necessary, for network control and signaling.

[0057] The DU 230 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more Rus 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the 3^rd Generation Partnership Project (3GPP). In some aspects, the DU 230 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 230, or with the control functions hosted by the CU 210. [0058] Lower-layer functionality can be implemented by one or more RUs 240. In some deployments, an RU 240, controlled by a DU 230, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like), or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU(s) 240 can be implemented to handle over the air (OTA) communication with one or more UEs 115. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU(s) 240 can be controlled by the corresponding DU 230. In some scenarios, this configuration can enable the DU(s) 230 and the CU 210 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

[0059] The SMO Framework 205 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non- virtualized network elements, the SMO Framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an 01 interface). For virtualized network elements, the SMO Framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an 02 interface). Such virtualized network elements can include, but are not limited to, CUs 210, DUs 230, Rus 240 and Near-RT RICs 225. In some implementations, the SMO Framework 205 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 211, via an 01 interface. Additionally, in some implementations, the SMO Framework 205 can communicate directly with one or more Rus 240 via an 01 interface. The SMO Framework 205 also may include a Non-RT RIC 215 configured to support functionality of the SMO Framework 205.

[0060] The Non-RT RIC 215 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 225. The Non-RT RIC 215 may be coupled to or communicate with (such as via an Al interface) the Near-RT RIC 225. The Near-RT RIC 225 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 210, one or more DUs 230, or both, as well as an O-eNB, with the Near-RT RIC 225.

[0061] In some implementations, to generate AI/ML models to be deployed in the Near- RT RIC 225, the Non-RT RIC 215 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 225 and may be received at the SMO Framework 205 or the Non-RT RIC 215 from non-network data sources or from network functions. In some examples, the Non-RT RIC 215 or the Near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 215 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 205 (such as reconfiguration via 01) or via creation of RAN management policies (such as Al policies).

[0062] In some aspects, a first UE 115 may receive, from a plurality of sidelink UEs 115, a plurality of sidelink communications. The first UE 115 may transmit, to one or more of the plurality of sidelink UEs 115 based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications. In some aspects, the priority order may be based on priorities associated with the plurality of sidelink communications and priorities associated with HARQ feedback opportunities.

[0063] In some aspects, a first UE 115 may receive, from a first plurality of sidelink UEs 115, a first plurality of sidelink communications. The first UE 115 may transmit, to a second plurality of sidelink UEs 115, a second plurality of sidelink communications and communicate hybrid automatic repeat request (HARQ) feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications. The first UE 115 may communicate the HARQ feedback based on priorities associated with the first plurality of sidelink communications, priorities associated with the second plurality of sidelink communications, priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications, and priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

[0064] FIG. 3 illustrates a wireless communication network 300 according to some aspects of the present disclosure. FIG. 3 illustrates an example of a wireless communications network 300 that supports techniques for configuring multiple PSFCH opportunities for sidelink feedback in accordance with various aspects of the present disclosure. The wireless communications network 300 illustrates communication between a UE 115a and a UE 115b, which may be examples of corresponding devices described herein, including UEs 115 as described with reference to FIGS. 1 and 2. In some aspects, the UE 115a and the UE 115b may communicate within a geographic coverage area and communicate with each other via a communication link 305 and a communication link 310 operating in sidelink mode. In some implementations, the UE 115b may receive a configuration of multiple PSFCH opportunities 325 over multiple LBT sub-bands 330 and symbols corresponding to a PSSCH 315.

[0065] The wireless communications network 300, which may be an example of an NR system supporting NR sidelink communication, such as V2X communication, may support the transmission of feedback (such as HARQ feedback) over a PSFCH 320 for higher reliability for both unicast and groupcast transmissions. For example, the UE 115a or the UE 115b, or both, may transmit a HARQ response (such as an ACK or a NACK) over a PSFCH opportunity 325 responsive to sidelink communication between the UE 115a and the UE 115b, and the PSFCH may be arranged or otherwise configured as a global resource pool with pre-determined (e.g., pre-configured) mappings or assignments. In other words, in some cases, there may be multiple PSFCH opportunities 325 for one PSSCH. Such examples in which there may be a multiple PSFCH opportunities 325 for one PSSCH may include examples of unicast HARQ response (such that one UE 115 receives a data transmission and transmits feedback via PSFCH responsive to the data transmission and examples of groupcast HARQ response option 2 (such that multiple UEs 115 receive a data transmission and each transmit or refrain from transmitting a PSFCH 320 responsive to the data transmission).

[0066] In some aspects, one or more PSFCH opportunities 325 are mapped or assigned to one PSSCH 315 and in which the UE 115a transmits a data transmission to the UE 115b over a PSSCH 315, the UE 115b may determine the PSFCH opportunities 325 that are mapped or assigned to the PSSCH 315 over which the UE 115a transmits the data transmission, and the UE 115b may transmit ACK/NACK feedback responsive to the data transmission over one or more PSFCH opportunities 325 accordingly. In some cases, such a mapping or assignment may be pre-configured for each PSSCH 315 resource over which a UE 115 may transmit.

[0067] In some aspects, each PSSCH 315 may be mapped to multiple PSFCH opportunities 325, and each different PSFCH opportunity 325 may correspond to a different set of physical resource blocks (PRBs) in a symbol period, such as a PSFCH symbol period. In some cases, each set of PRBs in the PSFCH symbol period may include a configurable quantity of PRBs.

[0068] In some aspects, the UE 115a and the UE 115b may communicate over an unlicensed radio frequency spectrum band. In such cases in which the UE 115a and the UE 115b communicate over an unlicensed radio frequency spectrum band, the LIE 115a and the UE 115b may perform LBT (e.g., an LBT procedure or a channel access procedure) prior to transmitting to support coexistence with other radio access technologies (RATs). In some aspects, the UE 115b may perform an LBT prior to transmitting the ACK/NACK feedback (e.g., a HARQ response) over one or more PSFCH opportunities 325. In some cases, however, the PSFCH opportunity 325 may be occupied or otherwise unavailable such that the LBT for the PSFCH opportunity 325 may fail. As such, the UE 115b may be unable to gain channel access for the PSFCH opportunity 325 and may be unable to transmit the ACK/NACK to the UE 115a over the PSFCH opportunity 325. The UE 115a, failing to receive the ACK/NACK feedback from the UE 115b over the PSFCH opportunity 325 corresponding to (e.g., mapped or assigned to) the PSSCH 315 carrying the data transmission, may determine or otherwise assume that the UE 115b failed to successfully receive the data transmission. The UE 115a may accordingly re-transmit the data transmission to the UE 115b over a second PSSCH 315, which may be unnecessary in cases in which the UE 115b successfully received the initial data transmission and experienced an LBT failure when attempting to transmit the associated ACK/NACK feedback.

[0069] In some aspects, the UE 115b may receive a configuration of multiple PSFCH opportunities 325, such as a PSFCH opportunity 325a, a PSFCH opportunity 325b, and a PSFCH opportunity 325c, over multiple LBT sub-bands 330, such as over an LBT sub-band 330a and an LBT sub-band 330b. In other words, one PSSCH over which the UE 115a may transmit the data transmission to the UE 115b (and that requests HARQ response) may correspond to multiple PSFCH opportunities 325 over multiple LBT subbands 330 and/or multiple symbols.

[0070] For example, the UE 115a may transmit the data transmission over a PSSCH 315 that corresponds to multiple PSFCH opportunities 325 including the PSFCH opportunity 325a located in the LBT sub-band 330a and in a first PSFCH symbol, the PSFCH opportunity 325b located in the LBT sub-band 330b and in the first PSFCH symbol, and the PSFCH opportunity 325c located in the LBT sub-band 330b and in a second PSFCH symbol. As such, the UE 115b may perform an LBT procedure for one or more of the PSFCH opportunities 325 to determine which of the multiple PSFCH opportunities 325 are available (e.g., which of the multiple PSFCH opportunities 325 pass LBT). In some aspects, the UE 115b may determine that one or more of the multiple PSFCH opportunities 325 are available (e.g., pass LBT) and may transmit the ACK/NACK associated with the data transmission over at least one of the one or more PSFCH opportunities 325 that are available. However, due to limited number of PSFCH opportunities 325 (e.g., HARQ feedback opportunities) and the uncertainties of the UE 115 to gain the channel in an unlicensed (e.g., shared) frequency band, the UE 115 may transmit the HARQ feedback based on a priority order. In some aspects, the priority order may be based on priorities associated with the plurality of PSSCH 315 communications and/or priorities associated with PSFCH opportunities 325 (e.g., HARQ feedback opportunities).

[0071] FIGS. 4A-4D illustrate priority ordering for multiple PSFCH opportunities. In some aspects, a first sidelink UE (e.g., the UE 115 or the UE 700) may receive a plurality of sidelink communications from a plurality of sidelink UEs (e.g., the UEs 115 or the UEs 700). In this regard, the first sidelink UE may receive physical sidelink control channel (PSCCH) communications, physical sidelink shared channel (PSSCH) communications, or other suitable sidelink communications. The first sidelink UE may receive the plurality of sidelink communications over different time resources and/or different frequency resources. Each sidelink communication of the plurality of sidelink communications may have an associated priority level. The priority level associated with the PSSCH communication may be based on a latency requirement and/or a reliability requirement associated with the PSSCH communication. The first sidelink UE may receive an indicator of the priority level associated with the PSSCH communication from the transmitting sidelink UE of the plurality of sidelink UEs. [0072] In some aspects, the first sidelink UE may transmit hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications to one or more of the plurality of sidelink UEs. The first sidelink UE may transmit the HARQ feedback based on a priority order. In some aspects, the first sidelink UE may transmit a HARQ feedback indicator indicating whether the PSSCH communication (e.g., PSSCH communication carrying a transport block (TB)) was successfully received (e.g., successfully decoded). In this regard, the first sidelink UE may transmit the HARQ feedback (e.g., HARQ ACK/NACK) via a physical sidelink feedback channel (PFSCH). If the first sidelink UE decodes the TB successfully, the first sidelink UE may transmit a HARQ acknowledgement (ACK) to the UE that transmitted the TB to the first sidelink UE. Conversely, if the first sidelink UE fails to decode the TB successfully, the first sidelink UE may transmit a HARQ negativeacknowledgement (NACK) to the UE that transmitted the TB. The first sidelink UE may be scheduled with multiple HARQ feedback opportunities to transmit the HARQ feedback. Due to limited number of HARQ feedback opportunities and the uncertainties of the first sidelink UE to gain the channel in an unlicensed (e.g., shared) frequency band, the first sidelink UE may transmit the HARQ feedback based on a priority order. In some aspects, the priority orders indicated in FIGS. 4A-4D may be based on priorities associated with the plurality of sidelink communications and/or priorities associated with HARQ feedback opportunities.

[0073] In some aspects, the priorities associated with the plurality of sidelink communications may be represented as priority level values. In some aspects, a priority level value may include a channel access priority class (CAPC). A higher priority communication may be assigned a higher priority (e.g., a lower CAPC value). A CAPC may include integer values of 1, 2, 3, or 4. In some aspects, a lower priority level value may be associated with a sidelink communication having a higher priority than a sidelink communication associated with a higher priority level value. A CAPC of 1 may have the highest priority and a CAPC of 4 may have the lowest priority.

[0074] In some aspects, the priorities associated with HARQ feedback opportunities may be represented as HARQ feedback opportunity index values. The HARQ feedback opportunity index values may include any number of integer values corresponding to the HARQ feedback opportunities. For example, the first sidelink UE may have four HARQ feedback opportunities having index values of 1, 2, 3, or 4. In some aspects, the HARQ feedback opportunity index may indicate a time order. A lower HARQ feedback opportunity index value (e.g., index value 1) may be associated with a HARQ feedback opportunity earlier in time than a HARQ feedback opportunity associated with a higher HARQ feedback opportunity index value (e.g., index value 2, 3, or 4).

[0075] In some aspects, the first sidelink UE may transmit the HARQ feedback in a priority order based on the first sidelink UE having a limitation. In some aspects, the limitation may include a processing limitation and/or a memory limitation that limits the first sidelink UE in processing the HARQ feedback. In some aspects, the limitation may include a battery power limitation that limits the first sidelink UE in processing the HARQ feedback. In some aspects, the limitation may include a transmit power limitation that limits the maximum power level at which the first sidelink UE may transmit the HARQ feedback.

[0076] The first sidelink UE may transmit the HARQ feedback in PSFCH occasions. In some aspects, when the number (N_{scfl TxPSFCH}) of PSFCHs to be transmitted in a given PSFCH transmit occasion across different PSFCH opportunities and priority levels is less than the maximum number of PSFCHs the first sidelink UE is capable of transmitting (Nmax,ptfch), the first sidelink UE may transmit all N_Sch,Tx, PSFCH PSFCHs when transmit power is not limited.

[0077] In some aspects, the lower bound X for the number of PSFCH transmissions may be determined by at least four options in which M(i,j) is the number of PSFCHs with priority level value i and the jth HARQ feedback opportunity in which there are potential L HARQ feedback opportunities and K priority values. For example, the priority order may be based on priorities associated with the plurality of sidelink communications and/or priorities associated with HARQ feedback opportunities. For example, when the HARQ feedback associated with the sidelink communications received by the first sidelink UE has the same priority level value (e.g., the same CAPC value), the priority order may be an ascending order of HARQ feedback opportunity index values.

[0078] A first option for the lower bound X may include X — i,j^

summing

over j associated with the lowest priority level value i first then j, in which

are the largest values satisfying PQ, PSFCH + 10 f° 7io(2^g) + ^aPSFCH ‘ PL + 101og₁₀ (X) < P_CMAX AS described with reference to FIG. 4A, the priority order may start at reference numeral 402a in which the highest priority in the priority order may be Mi.i. The priority order may follow the path indicated by the arrows in FIG. 4A. The priority order may follow the order Mi,i, Mi, 2. M2.1, M2, 2, Ms,i. M3.2, M4,I, M 2. Although the example of FIG. 4A shows four priority level values and two HARQ feedback opportunity index values, the present disclosure is not so limited and may include any number of priority level values and any number of HARQ feedback opportunity index values.

[0079] A second option for the lower bound X may include X = j over HARQ opportunities from the last

(e.g., highest HARQ feedback opportunity index value) to the first (e.g., lowest HARQ opportunity index value) associated with lowest priority level value i first then j, in which L_i, K') are the largest values satisfying PQ, PSFCH

+ ^aPSFCH ’

PL + 101og₁₀ (X) < P_CMAX ■ Iⁿ the second option, the later HARQ feedback opportunities for a given priority level value are higher in the priority order. As described with reference to FIG. 4B, the priority order may start at reference numeral 402b in which the highest priority in the priority order may be Mi.2. The priority order may follow the path indicated by the arrows in FIG. 4B. The priority order may follow the order Mi, 2, Mi,i, M2, 2, M2J, M3, 2, M34, M4,2, M44. Although the example of FIG. 4B shows four priority level values and two HARQ feedback opportunity index values, the present disclosure is not so limited and may include any number of priority level values and any number of HARQ feedback opportunity index values.

[0080] A third option for the lower bound X may include X =

summing

over priority value z associated with the earliest HARQ feedback opportunity first (e.g., lowest HARQ feedback opportunity index value) and thenj, in which (L, Kj') are the largest values satisfying PO,PSFCH +

+ < PSFCH '

PL + 101og₁₀ (X) < P_CMAX . In the third option, the later HARQ feedback opportunities are lower in the priority order. As described with reference to FIG. 4C, the priority order may start at reference numeral 402c in which the highest priority in the priority order may be Mi,i. The priority order may follow the path indicated by the arrows in FIG. 4C. The priority order may follow the order Mi,i, M24, M34, M4,I, Mi, 2, M2, 2, M3, 2, M4,2. Although the example of FIG. 4C shows four priority level values and two HARQ feedback opportunity index values, the present disclosure is not so limited and may include any number of priority level values and any number of HARQ feedback opportunity index values.

[0081] A fourth option for the lower bound X may include X — summing M_i:J- over priority value z associated with the

latest HARQ feedback opportunity first (e.g., highest HARQ feedback opportunity index value) and then j, in which (£', Kj) are the largest values satisfying PQ_IPSFCH + 10 log_w(2^(r) + a_PSFCH ■ PL + 101og₁₀(X) < P_CMAX where 1 < Kj < K and 1 < L' < L. In the fourth option, the later HARQ feedback opportunities are higher in the priority order for all of the priority level values. As described with reference to FIG. 4D, the priority order may start at reference numeral 402d in which the highest priority in the priority order may be Mi, 2. The priority order may follow the path indicated by the arrows in FIG. 4D. The priority order may follow the order M1.2. M2.2. Ms,2. M4.2. Mi.i, M24, M3,I. M4.1. Although the example of FIG. 4D shows four priority level values and two HARQ feedback opportunity index values, the present disclosure is not so limited and may include any number of priority level values and any number of HARQ feedback opportunity index values. [0082] In some aspects, when the number of intended HARQ feedback transmissions across all HARQ feedback opportunities and priority level values is greater than the maximum number the HARQ feedback transmissions the first sidelink UE supports (e.g., due to limitations associated with the first sidelink UE), the priority order may be used to limit (e.g., cap) the number of HARQ feedback transmissions. For example, the priority order may include at least one of a descending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values, an ascending order of the priority level values and then a descending order of the HARQ feedback opportunity index values, an ascending order of the priority level values and then an ascending order of the HARQ feedback opportunity index values, or an ascending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values.

[0083] FIG. 5 is a signaling diagram of a wireless communication method 500 according to some aspects of the present disclosure. Actions of the communication method 500 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a communication device or other suitable means for performing the actions. For example, a wireless communication device, such as the UE 115 or UE 700, may utilize one or more components, such as the processor 702, the memory 704, the HARQ priority order module 708, the transceiver 710, the modem 712, and the one or more antennas 716, to execute aspects of method 500. [0084] At action 502, the UE 115j may receive a sidelink communication A from the UE 115i. In this regard, the UE 115j may receive a physical sidelink control channel (PSCCH) communication, a physical sidelink shared channel (PSSCH) communication, or other suitable sidelink communication from UE 115j .

[0085] At action 504, the UE 115j may receive a sidelink communication B from the UE 115k. In this regard, the UE 115j may receive a physical sidelink control channel (PSCCH) communication, a physical sidelink shared channel (PSSCH) communication, or other suitable sidelink communication from UE 115k.

[0086] At action 506, the UE 115j may receive a sidelink communication C from the UE 115i. In this regard, the UE 115j may receive a physical sidelink control channel (PSCCH) communication, a physical sidelink shared channel (PSSCH) communication, or other suitable sidelink communication from UE 115i.

[0087] At action 508, the UE 115j may receive a sidelink communication D from the UE 115k. In this regard, the UE 115j may receive a physical sidelink control channel (PSCCH) communication, a physical sidelink shared channel (PSSCH) communication, or other suitable sidelink communication from UE 115k.

[0088] The UE 115 j may receive the sidelink communications A, B, C, and D over different time resources and/or different frequency resources. Each sidelink communication A, B, C, and D may have an associated priority level. The priority level associated with the PSSCH communication may be based on a latency requirement and/or a reliability requirement associated with the PSSCH communication. The UE 115i may receive indicators of the priority levels associated with the PSSCH communications from the transmitting sidelink UEs 115j and 115k.

[0001] At action 510, the UE 115j may determine a HARQ feedback priority order for transmitting HARQ feedback (e.g., ACK/NACK) to the UEs 115j and 115k associated with the sidelink communications received at actions 502, 504, 506, and 508. Due to limited number of HARQ feedback opportunities and the uncertainties of the UE 115j to gain the channel in an unlicensed (e.g., shared) frequency band, the UE 115j may transmit the HARQ feedback based on a priority order. In some aspects, the priority order may be based on priorities associated with the sidelink communications A, B, C, and D and/or priorities associated with HARQ feedback opportunities.

[0002] In some aspects, the priorities associated with the sidelink communications A, B, C, and D may be represented as priority level values. In some aspects, a priority level value may include a channel access priority class (CAPC). A higher priority communication may be assigned a higher priority (e.g., a lower CAPC value). A CAPC may include integer values of 1, 2, 3, or 4. In some aspects, a lower priority level value may be associated with a sidelink communication having a higher priority than a sidelink communication associated with a higher priority level value. A CAPC of 1 may have the highest priority and a CAPC of 4 may have the lowest priority.

[0003] In some aspects, the priorities associated with HARQ feedback opportunities may be represented as HARQ feedback opportunity index values. The HARQ feedback opportunity index values may include any number of integer values corresponding to the HARQ feedback opportunities. For example, the UE 115j may have four HARQ feedback opportunities having index values of 1, 2, 3, or 4. In some aspects, the HARQ feedback opportunity index may indicate a time order. A lower HARQ feedback opportunity index value (e.g., index value 1) may be associated with a HARQ feedback opportunity earlier in time than a HARQ feedback opportunity associated with a higher HARQ feedback opportunity index value (e.g., index value 2, 3, or 4). [0004] In some aspects, the UE 115j may transmit the HARQ feedback in a priority order based on the UE 115j having a limitation. In some aspects, the limitation may include a processing limitation and/or a memory limitation that limits the UE 115j in processing the HARQ feedback. In some aspects, the limitation may include a battery power limitation that limits the UE 115j in processing the HARQ feedback. In some aspects, the limitation may include a transmit power limitation that limits the maximum power level at which the UE 115j may transmit the HARQ feedback.

[0005] The UE 115j may select a priority order from a number of options as described with reference to FIG. 4. In the Example, of FIG. 5, the UE may select the third option. In the third option, the later HARQ feedback opportunities are lower in the priority order and the priority level values are ordered in an ascending order.

[0006] At action 512, the UE 115j may transmit HARQ feedback for sidelink communications B and D to the UE 115k. The UE 115j may transmit HARQ feedback for sidelink communications B and D to the UE 115k based on the priority level values for sidelink communications B and D being lower than priority level values for sidelink communications A and C. A lower priority level value (e.g., CAPC index) may correspond to a higher priority sidelink communication.

[0007] At action 514, the UE 115j may transmit HARQ feedback for sidelink communications A and C to the UE 115i. The UE 115j may transmit HARQ feedback for sidelink communications A and C to the UE 115i based on the priority level values for sidelink communications A and C being higher than priority level values for sidelink communications B and D. A higher priority level value (e.g., CAPC index) may correspond to a lower priority sidelink communication.

[0089] FIG. 6 is a signaling diagram of a wireless communication method 600 according to some aspects of the present disclosure. Actions of the communication method 600 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a communication device or other suitable means for performing the actions. For example, a wireless communication device, such as the UE 115 or UE 700, may utilize one or more components, such as the processor 702, the memory 704, the HARQ priority order module 708, the transceiver 710, the modem 712, and the one or more antennas 716, to execute aspects of method 600. [0090] At action 602, the UE 115j may receive a sidelink communication A from the UE 115i. In this regard, the UE 115j may receive a physical sidelink control channel (PSCCH) communication, a physical sidelink shared channel (PSSCH) communication, or other suitable sidelink communication from UE 115j .

[0091] At action 604, the UE 115j may transmit a sidelink communication B to the UE 115k. In this regard, the UE 115j may transmit a physical sidelink control channel (PSCCH) communication, a physical sidelink shared channel (PSSCH) communication, or other suitable sidelink communication to the UE 115k.

[0092] At action 606, the UE 115j may receive a sidelink communication C from the UE 115i. In this regard, the UE 115j may receive a physical sidelink control channel (PSCCH) communication, a physical sidelink shared channel (PSSCH) communication, or other suitable sidelink communication to the UE 115i.

[0093] At action 608, the UE 115j may transmit a sidelink communication D to the UE 115k. In this regard, the UE 115j may transmit a physical sidelink control channel (PSCCH) communication, a physical sidelink shared channel (PSSCH) communication, or other suitable sidelink communication from UE 115k.

[0094] The UE 115j may receive the sidelink communications A, B, C, and D over different time resources and/or different frequency resources. Each sidelink communication A, B, C, and D may have an associated priority level. The priority level associated with the PSSCH communication may be based on a latency requirement and/or a reliability requirement associated with the PSSCH communication. The UE 115i may receive indicators of the priority levels associated with the PSSCH communications from the transmitting sidelink UEs 115j and 115k.

[0008] At action 610, the UE 115j may determine a HARQ feedback priority order for transmitting HARQ feedback (e.g., ACK/NACK) to the UEs 115j associated with the sidelink communications received at actions 602 and 606 and receiving HARQ feedback from the 115k associated with the sidelink communications transmitted at actions 604 and 608.

[0009] In some aspects, the HARQ feedback opportunities for the sidelink communications A and C and the HARQ feedback opportunities for the sidelink communications B and D may be scheduled in the same symbol of the same slot. When the transmission of HARQ feedback and the reception of HARQ feedback overlaps in time (e.g., the same symbol of the same slot), the UE 115j may determine a priority order for the transmission and reception of HARQ feedback. In this regard, the priority order may be based on priorities associated with the sidelink communications A and C, priorities associated with the sidelink communications B and D and priorities associated with HARQ feedback opportunities.

[0010] In some aspects, the priorities associated with the sidelink communications A, B, C, and D may be represented as priority level values. In some aspects, a priority level value may include a channel access priority class (CAPC). A higher priority communication may be assigned a higher priority (e.g., a lower CAPC value). A CAPC may include integer values of 1, 2, 3, or 4. In some aspects, a lower priority level value may be associated with a sidelink communication having a higher priority than a sidelink communication associated with a higher priority level value. A CAPC of 1 may have the highest priority and a CAPC of 4 may have the lowest priority.

[0011] In some aspects, the priorities associated with HARQ feedback opportunities may be represented as HARQ feedback opportunity index values. The HARQ feedback opportunity index values may include any number of integer values corresponding to the HARQ feedback opportunities. For example, the UE 115j may have four HARQ feedback opportunities having index values of 1, 2, 3, or 4. In some aspects, the HARQ feedback opportunity index may indicate a time order. A lower HARQ feedback opportunity index value (e.g., index value 1) may be associated with a HARQ feedback opportunity earlier in time than a HARQ feedback opportunity associated with a higher HARQ feedback opportunity index value (e.g., index value 2, 3, or 4).

[0012] The UE 115j may select a priority order from a number of options as described with reference to FIG. 4. In the Example, of FIG. 5, the UE may select the third option. In the third option, the later HARQ feedback opportunities are lower in the priority order and the priority level values are ordered in an ascending order.

[0013] At action 612, the UE 115j may receive HARQ feedback for sidelink communication B from the UE 115k. The UE 115j may receive HARQ feedback for sidelink communication B based on the priority level values for sidelink communications A, B, C, and D being equal and sidelink communication B having a highest HARQ feedback opportunity index. The HARQ feedback opportunity with the highest index may be prioritized as it may be a last opportunity for the UE 115k to transmit HARQ feedback to the UE 115j.

[0014] At action 614, the UE 115j may transmit HARQ feedback for sidelink communication A to the UE 115i. The UE 115j may transmit HARQ feedback for sidelink communication A based on the priority level values for sidelink communications A, B, C, and D being equal and sidelink communication A having a next highest HARQ feedback opportunity index compared to HARQ feedback opportunity index for sidelink communication B.

[0015] At action 616, the UE 115j may transmit HARQ feedback for sidelink communication C to the UE 115i. The UE 115j may transmit HARQ feedback for sidelink communication C based on the priority level values for sidelink communications A, B, C, and D being equal and sidelink communication C having a next highest HARQ feedback opportunity index compared to HARQ feedback opportunity index for sidelink communication A.

[0016] At action 618, the UE 115j may receive HARQ feedback for sidelink communication D from the UE 115k. The UE 115j may receive HARQ feedback for sidelink communication D based on the priority level values for sidelink communications A, B, C, and D being equal and sidelink communication D having a lowest HARQ feedback opportunity index compared to HARQ feedback opportunity index for sidelink communications A, B, and C.

[0095] FIG. 7 is a block diagram of an exemplary UE 700 according to some aspects of the present disclosure. The UE 700 may be the UE 115 in the network 100, 200, or 300 as discussed above. As shown, the UE 700 may include a processor 702, a memory 704, a HARQ priority order module 708, a transceiver 710 including a modem subsystem 712 and a radio frequency (RF) unit 714, and one or more antennas 716. These elements may be coupled with each other and in direct or indirect communication with each other, for example via one or more buses.

[0096] The processor 702 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 702 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. [0097] The memory 704 may include a cache memory (e.g., a cache memory of the processor 702), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some instances, the memory 704 includes a non-transitory computer- readable medium. The memory 704 may store instructions 706. The instructions 706 may include instructions that, when executed by the processor 702, cause the processor 702 to perform the operations described herein with reference to the UEs 115 in connection with aspects of the present disclosure, for example, aspects of FIGS. 3, 4A - 4D. Instructions 706 may also be referred to as code. The terms “instructions” and “code” should be interpreted broadly to include any type of computer-readable statement(s). For example, the terms “instructions” and “code” may refer to one or more programs, routines, sub-routines, functions, procedures, etc. “Instructions” and “code” may include a single computer-readable statement or many computer-readable statements.

[0098] The HARQ priority order module 708 may be implemented via hardware, software, or combinations thereof. For example, the HARQ priority order module 708 may be implemented as a processor, circuit, and/or instructions 706 stored in the memory 704 and executed by the processor 702. In some aspects, the HARQ priority order module 708 may implement the aspects of FIGS. 3, 4A-4D, 5, and 6. For example, the HARQ priority order module 708 may receive, from a plurality of sidelink UEs 115, a plurality of sidelink communications. The HARQ priority order module 708 may transmit, to one or more of the plurality of sidelink UEs 115 based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications. In some aspects, the priority order may be based on priorities associated with the plurality of sidelink communications and priorities associated with HARQ feedback opportunities.

[0099] In some aspects, the HARQ priority order module 708 may receive, from a first plurality of sidelink UEs 115, a first plurality of sidelink communications. The HARQ priority order module 708 may transmit, to a second plurality of sidelink UEs 115, a second plurality of sidelink communications and communicate hybrid automatic repeat request (HARQ) feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications. The HARQ priority order module 708 may communicate the HARQ feedback based on priorities associated with the first plurality of sidelink communications, priorities associated with the second plurality of sidelink communications, priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications, and priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

[0100] As shown, the transceiver 710 may include the modem subsystem 712 and the RF unit 714. The transceiver 710 can be configured to communicate bi-directionally with other devices, such as the BSs 105 and/or the UEs 115. The modem subsystem 712 may be configured to modulate and/or encode the data from the memory 704 and the according to a modulation and coding scheme (MCS), e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 714 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem 712 (on outbound transmissions) or of transmissions originating from another source such as a UE 115 or a BS 105. The RF unit 714 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 710, the modem subsystem 712 and the RF unit 714 may be separate devices that are coupled together to enable the UE 700 to communicate with other devices.

[0101] The RF unit 714 may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas 716 for transmission to one or more other devices. The antennas 716 may further receive data messages transmitted from other devices. The antennas 716 may provide the received data messages for processing and/or demodulation at the transceiver 710. The antennas 716 may include multiple antennas of similar or different designs in order to sustain multiple transmission links. The RF unit 714 may configure the antennas 716.

[0102] In some instances, the UE 700 can include multiple transceivers 710 implementing different RATs (e.g., NR and LTE). In some instances, the UE 700 can include a single transceiver 710 implementing multiple RATs (e.g., NR and LTE). In some instances, the transceiver 710 can include various components, where different combinations of components can implement RATs.

[0103] FIG. 8 is a block diagram of an exemplary network unit 800 according to some aspects of the present disclosure. The network unit 800 may be the BS 105, the CU 210, the DU 230, or the RU 240, as discussed above. As shown, the network unit 800 may include a processor 802, a memory 804, a HARQ priority order module 808, a transceiver 810 including a modem subsystem 812 and a RF unit 814, and one or more antennas 816. These elements may be coupled with each other and in direct or indirect communication with each other, for example via one or more buses.

[0104] The processor 802 may have various features as a specific-type processor. For example, these may include a CPU, a DSP, an ASIC, a controller, a FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 802 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0105] The memory 804 may include a cache memory (e.g., a cache memory of the processor 802), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some instances, the memory 804 may include a non-transitory computer- readable medium. The memory 804 may store instructions 806. The instructions 806 may include instructions that, when executed by the processor 802, cause the processor 802 to perform operations described herein, for example, aspects of FIGS. 3, 4A-4d, 5, and 6. Instructions 806 may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement(s).

[0106] The HARQ priority order module 808 may be implemented via hardware, software, or combinations thereof. For example, the HARQ priority order module 808 may be implemented as a processor, circuit, and/or instructions 806 stored in the memory 804 and executed by the processor 802.

[0107] In some aspects, the HARQ priority order module 808 may implement the aspects of FIGS. 3, 4A-4d, 5, and 6. For example, the HARQ priority order module 808 may transmit, to a sidelink UE, a configuration associated with multiple PSFCH opportunities. Additionally or alternatively, the HARQ priority order module 808 can be implemented in any combination of hardware and software, and may, in some implementations, involve, for example, processor 802, memory 804, instructions 806, transceiver 810, and/or modem 812.

[0108] As shown, the transceiver 810 may include the modem subsystem 812 and the RF unit 814. The transceiver 810 can be configured to communicate bi-directionally with other devices, such as the UEs 115 and/or 700. The modem subsystem 812 may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 814 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem 812 (on outbound transmissions) or of transmissions originating from another source such as a UE 115 or UE 700. The RF unit 814 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 810, the modem subsystem 812 and/or the RF unit 814 may be separate devices that are coupled together at the network unit 800 to enable the network unit 800 to communicate with other devices.

[0109] The RF unit 814 may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas 816 for transmission to one or more other devices. This may include, for example, a configuration indicating a plurality of subslots within a slot according to aspects of the present disclosure. The antennas 816 may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver 810. The antennas 816 may include multiple antennas of similar or different designs in order to sustain multiple transmission links.

[0110] In some instances, the network unit 800 can include multiple transceivers 810 implementing different RATs (e.g., NR and LTE). In some instances, the network unit 800 can include a single transceiver 810 implementing multiple RATs (e.g., NR and LTE). In some instances, the transceiver 810 can include various components, where different combinations of components can implement RATs.

[0111] FIG. 9 is a flow diagram of a communication method 900 according to some aspects of the present disclosure. Aspects of the method 900 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the actions. For example, a wireless communication device, such as the UE 115 or the UE 700, may utilize one or more components, such as the processor 702, the memory 704, the HARQ priority order module 708, the transceiver 710, the modem 712, and the one or more antennas 716, to execute aspects of method 900. The method 900 may employ similar mechanisms as in the networks 100, 200, and 300 and the aspects and actions described with respect to FIGS. 3-7. As illustrated, the method 900 includes a number of enumerated actions, but the method 900 may include additional actions before, after, and in between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0112] At action 910, the method 900 includes a first sidelink UE (e.g., the UE 115 or the UE 700) receiving a plurality of sidelink communications from a plurality of sidelink UEs (e.g., the UEs 115 or the UEs 700). In this regard, the first sidelink UE may receive physical sidelink control channel (PSCCH) communications, physical sidelink shared channel (PSSCH) communications, or other suitable sidelink communications. The first sidelink UE may receive the plurality of sidelink communications over different time resources and/or different frequency resources. Each sidelink communication of the plurality of sidelink communications may have an associated priority level. The priority level associated with the PSSCH communication may be based on a latency requirement and/or a reliability requirement associated with the PSSCH communication. The first sidelink UE may receive an indicator of the priority level associated with the PSSCH communication from the transmitting sidelink UE of the plurality of sidelink UEs.

[0113] At action 920, the method 900 includes the first sidelink UE transmitting hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications to one or more of the plurality of sidelink UEs. The first sidelink UE may transmit the HARQ feedback based on a priority order. In some aspects, the first sidelink UE may transmit a HARQ feedback indicator indicating whether the PSSCH communication (e.g., PSSCH communication carrying a transport block (TB)) was successfully received (e.g., successfully decoded). In this regard, the first sidelink UE may transmit the HARQ feedback (e.g., HARQ ACK/NACK) via a physical sidelink feedback channel (PFSCH). If the first sidelink UE decodes the TB successfully, the first sidelink UE may transmit a HARQ acknowledgement (ACK) to the UE that transmitted the TB to the first sidelink UE. Conversely, if the first sidelink UE fails to decode the TB successfully, the first sidelink UE may transmit a HARQ negative-acknowledgement (NACK) to the UE that transmitted the TB. The first sidelink UE may be scheduled with multiple HARQ feedback opportunities to transmit the HARQ feedback. Due to limited number of HARQ feedback opportunities and the uncertainties of the first sidelink UE to gain the channel in an unlicensed (e.g., shared) frequency band, the first sidelink UE may transmit the HARQ feedback based on a priority order. In some aspects, the priority order may be based on priorities associated with the plurality of sidelink communications and/or priorities associated with HARQ feedback opportunities.

[0114] In some aspects, the priorities associated with the plurality of sidelink communications may be represented as priority level values. In some aspects, a priority level value may include a channel access priority class (CAPC). A higher priority communication may be assigned a higher priority (e.g., a lower CAPC value). A CAPC may include integer values of 1, 2, 3, or 4. In some aspects, a lower priority level value may be associated with a sidelink communication having a higher priority than a sidelink communication associated with a higher priority level value. A CAPC of 1 may have the highest priority and a CAPC of 4 may have the lowest priority.

[0115] In some aspects, the priorities associated with HARQ feedback opportunities may be represented as HARQ feedback opportunity index values. The HARQ feedback opportunity index values may include any number of integer values corresponding to the HARQ feedback opportunities. For example, the first sidelink UE may have four HARQ feedback opportunities having index values of 1, 2, 3, or 4. In some aspects, the HARQ feedback opportunity index may indicate a time order. A lower HARQ feedback opportunity index value (e.g., index value 1) may be associated with a HARQ feedback opportunity earlier in time than a HARQ feedback opportunity associated with a higher HARQ feedback opportunity index value (e.g., index value 2, 3, or 4).

[0116] In some aspects, the first sidelink UE may transmit the HARQ feedback in a priority order based on the first sidelink UE having a limitation. In some aspects, the limitation may include a processing limitation and/or a memory limitation that limits the first sidelink UE in processing the HARQ feedback. In some aspects, the limitation may include a battery power limitation that limits the first sidelink UE in processing the HARQ feedback. In some aspects, the limitation may include a transmit power limitation that limits the maximum power level at which the first sidelink UE may transmit the HARQ feedback.

[0117] The first sidelink UE may transmit the HARQ feedback in PSFCH occasions. In some aspects, when the number (N_{scfl TxPSFCH}) of PSFCHs to be transmitted in a given PSFCH transmit occasion across different PSFCH opportunities and priority levels is less than the maximum number of PSFCHs the first sidelink UE is capable of transmitting (Nmax,psfch), the first sidelink UE may transmit all Nsch,Tx, PSFCH PSFCHs when transmit power is not limited. [0118] In some aspects, the lower bound X for the number of PSFCH transmissions may be determined by at least four options in which M(i,j) is the number of PSFCHs with priority level value i and the jth HARQ feedback opportunity in which there are potential L HARQ feedback opportunities and K priority values. For example, the priority order may be based on priorities associated with the plurality of sidelink communications and/or priorities associated with HARQ feedback opportunities. For example, when the HARQ feedback associated with the sidelink communications received by the first sidelink UE has the same priority level value (e.g., the same CAPC value), the priority order may be an ascending order of HARQ feedback opportunity index values.

[0119] A first option for the lower bound X may include X = max^l, Sf=i

summing M₍ j over j associated with the lowest priority level value i first then j, in which

are the largest values satisfying PQ, PSFCH +

+ ^aPSFCH ’

PL + 101og₁₀ (X) < P_CMAX AS described with reference to FIG. 5 A, the priority order may start at reference numeral 402a in which the highest priority in the priority order may be Ml,l. The priority order may follow the path indicated by the arrows in FIG. 5A. The priority order may follow the order Ml,l, Ml, 2, M2,l, M2, 2, M3,l, M3, 2, M4,l , M4,2. Although the example of FIG. 5 A shows four priority level values and two HARQ feedback opportunity index values, the present disclosure is not so limited and may include any number of priority level values and any number of HARQ feedback opportunity index values.

[0120] A second option for the lower bound X may include X = j over HARQ opportunities from the last

(e.g., highest HARQ feedback opportunity index value) to the first (e.g., lowest HARQ opportunity index value) associated with lowest priority level value i first then j, in which Li, KL) are the largest values satisfying Po, PSFCH + 10 log_w(2P') + a_PSFCH • PL + 101og₁₀ (X) < P_CMAX ■ Iⁿ the second option, the later HARQ feedback opportunities for a given priority level value are higher in the priority order. As described with reference to FIG. 5B, the priority order may start at reference numeral 402b in which the highest priority in the priority order may be Ml, 2. The priority order may follow the path indicated by the arrows in FIG. 5B. The priority order may follow the order Ml, 2, Ml,l, M2, 2, M2,l, M3, 2, M3,l, M4,2, M4,l. Although the example of FIG. 5B shows four priority level values and two HARQ feedback opportunity index values, the present disclosure is not so limited and may include any number of priority level values and any number of HARQ feedback opportunity index values.

[0121] A third option for the lower bound X may include X =

summing

j over priority value i associated with the earliest HARQ feedback opportunity first (e.g., lowest HARQ feedback opportunity index value) and then j, in which (L, Kj) are the largest values satisfying PO,PSFCH +

+ a_PSFCH ■

PL + 101og₁₀ (X) < P_CMAX ■ Iⁿ the third option, the later HARQ feedback opportunities are lower in the priority order. As described with reference to FIG. 5C, the priority order may start at reference numeral 402c in which the highest priority in the priority order may be M 1,1. The priority order may follow the path indicated by the arrows in FIG. 5C. The priority order may follow the order Ml,l, M2,l, M3,l, M4,l, Ml, 2, M2, 2, M3, 2, M4,2. Although the example of FIG. 5C shows four priority level values and two HARQ feedback opportunity index values, the present disclosure is not so limited and may include any number of priority level values and any number of HARQ feedback opportunity index values.

[0122] A fourth option for the lower bound X may include X = summing M_i:]- over priority value i associated with the

latest HARQ feedback opportunity first (e.g., highest HARQ feedback opportunity index value) and then j, in which (L', Kj) are the largest values satisfying PQ,PSFCH + 10 Zo#₁₀(2 ) + a_PSFCH • PL + 101og₁₀(X) < P_CMAX where 1 < Kj < K and 1 < L' < L. In the fourth option, the later HARQ feedback opportunities are higher in the priority order for all of the priority level values. As described with reference to FIG. 5D, the priority order may start at reference numeral 402d in which the highest priority in the priority order may be Ml, 2. The priority order may follow the path indicated by the arrows in FIG. 5D. The priority order may follow the order Ml, 2, M2, 2, M3, 2, M4,2, Ml,l, M2,l, M3,l, M4,l. Although the example of FIG. 5D shows four priority level values and two HARQ feedback opportunity index values, the present disclosure is not so limited and may include any number of priority level values and any number of HARQ feedback opportunity index values.

[0123] In some aspects, when the number of intended HARQ feedback transmissions across all HARQ feedback opportunities and priority level values is greater than the maximum number the HARQ feedback transmissions the first sidelink UE supports (e.g., due to limitations associated with the first sidelink UE), the priority order may be used to limit (e.g., cap) the number of HARQ feedback transmissions. For example, the priority order may include at least one of a descending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values, an ascending order of the priority level values and then a descending order of the HARQ feedback opportunity index values, an ascending order of the priority level values and then an ascending order of the HARQ feedback opportunity index values, or an ascending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values.

[0124] FIG. 10 is a flow diagram of a communication method 1000 according to some aspects of the present disclosure. Aspects of the method 1000 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the actions. For example, a wireless communication device, such as the UE 115 or the UE 700, may utilize one or more components, such as the processor 702, the memory 704, the HARQ priority order module 708, the transceiver 710, the modem 712, and the one or more antennas 716, to execute aspects of method 1000. The method 1000 may employ similar mechanisms as in the networks 100, 200, and 300 and the aspects and actions described with respect to FIGS. 3-7. As illustrated, the method 1000 includes a number of enumerated actions, but the method 1000 may include additional actions before, after, and in between the enumerated actions. In some aspects, one or more of the enumerated actions may be omitted or performed in a different order.

[0125] At action 1010, the method 1000 includes a first sidelink UE (e.g., the UE 115 or the UE 700) receiving a first plurality of sidelink communications from a first plurality of sidelink UEs (e.g., the UEs 115 or the UEs 700). In this regard, the first sidelink UE may receive physical sidelink control channel (PSCCH) communications, physical sidelink shared channel (PSSCH) communications, or other suitable sidelink communications. The first sidelink UE may receive the plurality of sidelink communications over different time resources and/or different frequency resources. Each sidelink communication of the first plurality of sidelink communications may have an associated priority level. The priority level associated with the PSSCH communication may be based on a latency requirement and/or a reliability requirement associated with the PSSCH communication. The first sidelink UE may receive an indicator of the priority level associated with the PSSCH communication from the transmitting sidelink UE of the first plurality of sidelink UEs. [0126] At action 1020, the method 1000 includes the first sidelink UE transmitting a second plurality of sidelink communications to a second plurality of sidelink UEs. In this regard, the first sidelink UE may transmit physical sidelink control channel (PSCCH) communications, physical sidelink shared channel (PSSCH) communications, or other suitable sidelink communications. The first sidelink UE may transmit the second plurality of sidelink communications over different time resources and/or different frequency resources. Each sidelink communication of the second plurality of sidelink communications may have an associated priority level. The priority level associated with the PSSCH communication may be based on a latency requirement and/or a reliability requirement associated with the PSSCH communication. The first sidelink UE may transmit an indicator of the priority level associated with the PSSCH communication to the receiving sidelink UE of the second plurality of sidelink UEs. [0127] At action 1030, the method 1000 includes the first sidelink UE communicating HARQ feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications. In this regard, the first sidelink UE may transmit HARQ feedback associated with the first plurality of sidelink communications received from the first plurality of UEs and/or the first sidelink UE may receive HARQ feedback associated with the second plurality of sidelink communications transmitted to the second plurality of UEs.

[0128] In some aspects, the HARQ feedback opportunities for the first plurality of sidelink communications and the HARQ feedback opportunities for the second plurality of sidelink communications may be scheduled in the same symbol of the same slot. When the transmission of HARQ feedback and the reception of HARQ feedback overlaps in time (e.g., the same symbol of the same slot), the first sidelink UE may determine a priority order for the transmission and reception of HARQ feedback. In this regard, the priority order may be based on priorities associated with the first plurality of sidelink communications, priorities associated with the second plurality of sidelink communications, priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications and/or priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

[0129] In some aspects, the priorities associated with the first plurality of sidelink communications may be represented as first priority level values. The priorities associated with the second plurality of sidelink communications may be represented as second priority level values. The priorities associated with the HARQ feedback opportunities for the first plurality of sidelink communications may be represented as first HARQ feedback opportunity index values. The priorities associated with the HARQ feedback opportunities for the second plurality of sidelink communications may be represented as second HARQ feedback opportunity index values.

[0130] In some aspects, the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications may include transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first priority level values being less than the second priority level values.

[0131] In some aspects, the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications may include receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second priority level values being less than the first priority level values.

[0132] In some aspects, when the first priority level values are equal to the second priority level values, the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications may include transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first HARQ feedback opportunity index values being greater than the second HARQ feedback opportunity index values.

[0133] In some aspects, when the first priority level values are equal to the second priority level values, the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications may include receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second HARQ feedback opportunity index values being greater than the first HARQ feedback opportunity index values.

[0134] In some aspects, the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications may include transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first HARQ feedback opportunity index values being greater than the second HARQ feedback opportunity index values. [0135] In some aspects, the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second HARQ feedback opportunity index values being greater than the first HARQ feedback opportunity index values.

[0136] Further aspects of the present disclosure include the following:

[0137] Aspect 1 includes a method of wireless communication performed by a first sidelink user equipment (UE), the method comprising receiving, from a plurality of sidelink UEs, a plurality of sidelink communications; and transmitting, to one or more of the plurality of sidelink UEs based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications, wherein the priority order is based on: priorities associated with the plurality of sidelink communications; and priorities associated with HARQ feedback opportunities.

[0138] Aspect 2 includes the method of aspect 1, wherein the transmitting the HARQ feedback comprises transmitting the HARQ feedback further based on a limitation associated with the first sidelink UE.

[0139] Aspect 3 includes the method of any of aspects 1-2, wherein the limitation comprises at least one of a processing limitation, a battery power limitation, or a transmit power limitation.

[0140] Aspect 4 includes the method of any of aspects 1-3, wherein: the priorities associated with the plurality of sidelink communications comprises priority level values; and the priorities associated with the HARQ feedback opportunities comprises HARQ feedback opportunity index values.

[0141] Aspect 5 includes the method of any of aspects 1-4, wherein for a same priority level value, the priority order comprises an ascending order of HARQ feedback opportunity index values.

[0142] Aspect 6 includes the method of any of aspects 1-5, wherein for a same priority level value, the priority order comprises a descending order of HARQ feedback opportunity index values.

[0143] Aspect 7 includes the method of any of aspects 1-6, wherein for a same HARQ feedback opportunity index value, the priority order comprises an ascending order of priority level values. [0144] Aspect 8 includes the method of any of aspects 1-7, wherein for a same HARQ feedback opportunity index value, the priority order comprises a descending order of priority level values.

[0145] Aspect 9 includes the method of any of aspects 1-8, wherein a lower HARQ feedback opportunity index value is associated with a HARQ feedback opportunity earlier in time than a HARQ feedback opportunity associated with a higher HARQ feedback opportunity index value.

[0146] Aspect 10 includes the method of any of aspects 1-9, wherein a lower priority level value is associated with a sidelink communication having a higher priority than a sidelink communication associated with a higher priority level value.

[0147] Aspect 11 includes the method of any of aspects 1-10, wherein the first sidelink UE supports a maximum number of HARQ feedback transmissions and the priority order comprises at least one of: a descending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values; an ascending order of the priority level values and then a descending order of the HARQ feedback opportunity index values; an ascending order of the priority level values and then an ascending order of the HARQ feedback opportunity index values; or an ascending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values.

[0148] Aspect 12 includes a method of wireless communication performed by a first sidelink user equipment (UE), the method comprising receiving, from a first plurality of sidelink UEs, a first plurality of sidelink communications; transmitting, to a second plurality of sidelink UEs, a second plurality of sidelink communications; and communicating hybrid automatic repeat request (HARQ) feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications based on: priorities associated with the first plurality of sidelink communications; priorities associated with the second plurality of sidelink communications; priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications; and priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

[0149] Aspect 13 includes the method of aspect 12, wherein the HARQ feedback opportunities for the first plurality of sidelink communications and the HARQ feedback opportunities for the second plurality of sidelink communications are scheduled in a same symbol of a same slot. [0150] Aspect 14 includes the method of any of aspects 12-13, wherein: the priorities associated with the first plurality of sidelink communications comprises first priority level values; the priorities associated with the second plurality of sidelink communications comprises second priority level values; the priorities associated with the HARQ feedback opportunities for the first plurality of sidelink communications comprises first HARQ feedback opportunity index values; and the priorities associated with the HARQ feedback opportunities for the second plurality of sidelink communications comprises second HARQ feedback opportunity index values.

[0151] Aspect 15 includes the method of any of aspects 12-14, wherein the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first priority level values being less than the second priority level values.

[0152] Aspect 16 includes the method of any of aspects 12-15, wherein the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second priority level values being less than the first priority level values.

[0153] Aspect 17 includes the method of any of aspects 12-16, wherein: the first priority level values are equal to the second priority level values; and the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first HARQ feedback opportunity index values being greater than the second HARQ feedback opportunity index values. [0154] Aspect 18 includes the method of any of aspects 12-17, wherein the first priority level values are equal to the second priority level values: and the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second HARQ feedback opportunity index values being greater than the first HARQ feedback opportunity index values. [0155] Aspect 19 includes the method of any of aspects 12-18, wherein the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first HARQ feedback opportunity index values being greater than the second HARQ feedback opportunity index values, [0156] Aspect 20 includes the method of any of aspects 12-19, wherein the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second HARQ feedback opportunity index values being greater than the first HARQ feedback opportunity index values. [0157] Aspect 21 includes 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 first sidelink UE perform any one of aspects 1-11.

[0158] Aspect 22 includes 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 first sidelink UE, cause the candidate relay UE to perform any one of aspects 12-20.

[0159] Aspect 23 includes a first sidelink UE comprising one or more means to perform any one or more of aspects 1-11.

[0160] Aspect 24 includes a first sidelink UE comprising one or more means to perform any one or more of aspects 12-20.

[0161] Aspect 25 includes a first sidelink UE comprising a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to perform any one or more of aspects 1-11.

[0162] Aspect 26 includes a first sidelink UE comprising a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to perform any one or more of aspects 12-20.

[0163] Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0164] The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0165] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, "or" as used in a list of items (for example, a list of items prefaced by a phrase such as "at least one of" or "one or more of") indicates an inclusive list such that, for example, a list of [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0166] As those of some skill in this art will by now appreciate and depending on the particular application at hand, many modifications, substitutions and variations can be made in and to the materials, apparatus, configurations and methods of use of the devices of the present disclosure without departing from the spirit and scope thereof. In light of this, the scope of the present disclosure should not be limited to that of the particular instances illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.

Claims

WHAT IS CLAIMED IS:

1. A method of wireless communication performed by a first sidelink user equipment (UE), the method comprising: receiving, from a plurality of sidelink UEs, a plurality of sidelink communications; and transmitting, to one or more of the plurality of sidelink UEs based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications, wherein the priority order is based on: priorities associated with the plurality of sidelink communications; and priorities associated with HARQ feedback opportunities.

2. The method of claim 1 , wherein the transmitting the HARQ feedback comprises transmitting the HARQ feedback further based on a limitation associated with the first sidelink UE, and wherein the limitation comprises at least one of a processing limitation, a battery power limitation, or a transmit power limitation.

3. The method of claim 1, wherein: the priorities associated with the plurality of sidelink communications comprises priority level values; and the priorities associated with the HARQ feedback opportunities comprises HARQ feedback opportunity index values.

4. The method of claim 3, wherein for a same priority level value, the priority order comprises one of a descending order or an ascending order of HARQ feedback opportunity index values.

5. The method of claim 3, wherein for a same HARQ feedback opportunity index value, the priority order comprises one of a descending order or an ascending order of priority level values.

6. The method of claim 3, wherein a lower HARQ feedback opportunity index value is associated with a HARQ feedback opportunity earlier in time than a HARQ feedback opportunity associated with a higher HARQ feedback opportunity index value.

7. The method of claim 3, wherein a lower priority level value is associated with a sidelink communication having a higher priority than a sidelink communication associated with a higher priority level value.

8. The method of claim 3, wherein the first sidelink UE supports a maximum number of HARQ feedback transmissions and the priority order comprises at least one of: a descending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values; an ascending order of the priority level values and then a descending order of the HARQ feedback opportunity index values; an ascending order of the priority level values and then an ascending order of the HARQ feedback opportunity index values; or an ascending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values.

9. A method of wireless communication performed by a first sidelink user equipment (UE), the method comprising: receiving, from a first plurality of sidelink UEs, a first plurality of sidelink communications; transmitting, to a second plurality of sidelink UEs, a second plurality of sidelink communications; and communicating hybrid automatic repeat request (HARQ) feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications based on: priorities associated with the first plurality of sidelink communications; priorities associated with the second plurality of sidelink communications; priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications; and priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

10. The method of claim 9, wherein the HARQ feedback opportunities for the first plurality of sidelink communications and the HARQ feedback opportunities for the second plurality of sidelink communications are scheduled in a same symbol of a same slot.

11. The method of claim 9, wherein: the priorities associated with the first plurality of sidelink communications comprises first priority level values; the priorities associated with the second plurality of sidelink communications comprises second priority level values; the priorities associated with the HARQ feedback opportunities for the first plurality of sidelink communications comprises first HARQ feedback opportunity index values; and the priorities associated with the HARQ feedback opportunities for the second plurality of sidelink communications comprises second HARQ feedback opportunity index values.

12. The method of claim 11, wherein the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises at least one of: transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first priority level values being less than the second priority level values; or receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second priority level values being less than the first priority level values.

13. The method of claim 11, wherein: the first priority level values are equal to the second priority level values; and the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises at least one of: transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first HARQ feedback opportunity index values being greater than the second HARQ feedback opportunity index values; or receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second HARQ feedback opportunity index values being greater than the first HARQ feedback opportunity index values.

14. The method of claim 11, wherein the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises transmitting the HARQ feedback associated with the first plurality of sidelink communications based on the first HARQ feedback opportunity index values being greater than the second HARQ feedback opportunity index values.

15. The method of claim 11, wherein the communicating the HARQ feedback associated with the first plurality of sidelink communications or the HARQ feedback associated with the second plurality of sidelink communications comprises receiving the HARQ feedback associated with the second plurality of sidelink communications based on the second HARQ feedback opportunity index values being greater than the first HARQ feedback opportunity index values.

16. A first sidelink user equipment (UE) comprising: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to: receive, from a plurality of sidelink UEs, a plurality of sidelink communications; and transmit, to one or more of the plurality of sidelink UEs based on a priority order, hybrid automatic repeat request (HARQ) feedback associated with a subset of the plurality of sidelink communications, wherein the priority order is based on: priorities associated with the plurality of sidelink communications; and priorities associated with HARQ feedback opportunities.

17. The first sidelink UE of claim 16, wherein the first sidelink LIE is further configured to transmit the HARQ feedback further based on a limitation associated with the first sidelink UE, and wherein the limitation comprises at least one of a processing limitation, a battery power limitation, or a transmit power limitation.

18. The first sidelink UE of claim 16, wherein: the priorities associated with the plurality of sidelink communications comprises priority level values; and the priorities associated with the HARQ feedback opportunities comprises HARQ feedback opportunity index values.

19. The first sidelink UE of claim 18, wherein for a same priority level value, the priority order comprises one of a descending order or an ascending order of HARQ feedback opportunity index values.

20. The first sidelink UE of claim 18, wherein for a same HARQ feedback opportunity index value, the priority order comprises one of a descending order or an ascending order of priority level values.

21. The first sidelink UE of claim 18, wherein a lower HARQ feedback opportunity index value is associated with a HARQ feedback opportunity earlier in time than a HARQ feedback opportunity associated with a higher HARQ feedback opportunity index value.

22. The first sidelink UE of claim 18, wherein a lower priority level value is associated with a sidelink communication having a higher priority than a sidelink communication associated with a higher priority level value.

23. The first sidelink UE of claim 18, wherein the first sidelink UE supports a maximum number of HARQ feedback transmissions and the priority order comprises at least one of: a descending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values; an ascending order of the priority level values and then a descending order of the HARQ feedback opportunity index values; an ascending order of the priority level values and then an ascending order of the HARQ feedback opportunity index values; or an ascending order of the HARQ feedback opportunity index values and then an ascending order of the priority level values.

24. A first sidelink user equipment (UE) comprising: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to: receive, from a first plurality of sidelink UEs, a first plurality of sidelink communications; transmit, to a second plurality of sidelink UEs, a second plurality of sidelink communications; and communicate hybrid automatic repeat request (HARQ) feedback associated with the first plurality of sidelink communications or HARQ feedback associated with the second plurality of sidelink communications based on: priorities associated with the first plurality of sidelink communications; priorities associated with the second plurality of sidelink communications; priorities associated with HARQ feedback opportunities for the first plurality of sidelink communications; and priorities associated with HARQ feedback opportunities for the second plurality of sidelink communications.

25. The first sidelink UE of claim 24, wherein the HARQ feedback opportunities for the first plurality of sidelink communications and the HARQ feedback opportunities for the second plurality of sidelink communications are scheduled in a same symbol of a same slot.

26. The first sidelink UE of claim 24, wherein: the priorities associated with the first plurality of sidelink communications comprises first priority level values; the priorities associated with the second plurality of sidelink communications comprises second priority level values; the priorities associated with the HARQ feedback opportunities for the first plurality of sidelink communications comprises first HARQ feedback opportunity index values; and the priorities associated with the HARQ feedback opportunities for the second plurality of sidelink communications comprises second HARQ feedback opportunity index values.

27. The first sidelink UE of claim 26, wherein the first sidelink UE is further configured to: transmit the HARQ feedback associated with the first plurality of sidelink communications based on the first priority level values being less than the second priority level values; or receive the HARQ feedback associated with the second plurality of sidelink communications based on the second priority level values being less than the first priority level values.

28. The first sidelink UE of claim 26, wherein: the first priority level values are equal to the second priority level values; and the first sidelink UE is further configured to: transmit the HARQ feedback associated with the first plurality of sidelink communications based on the first HARQ feedback opportunity index values being greater than the second HARQ feedback opportunity index values; or receive the HARQ feedback associated with the second plurality of sidelink communications based on the second HARQ feedback opportunity index values being greater than the first HARQ feedback opportunity index values.

29. The first sidelink UE of claim 26, wherein the first sidelink UE is further configured to: transmit the HARQ feedback associated with the first plurality of sidelink communications based on the first HARQ feedback opportunity index values being greater than the second HARQ feedback opportunity index values.

30. The first sidelink UE of claim 26, wherein the first sidelink UE is further configured to: receive the HARQ feedback associated with the second plurality of sidelink communications based on the second HARQ feedback opportunity index values being greater than the first HARQ feedback opportunity index values.