WO2023148637A1 - Configuring sidelink hybrid automatic repeat request feedback - Google Patents

Abstract

Apparatuses, methods, and systems are disclosed for configuring sidelink hybrid automatic repeat request feedback. One method (500) includes determining (502), at a first UE, to indicate non-numerical HARQ feedback indicator to a second UE. The method (500) includes configuring (504) SL HARQ feedback on a PSFCH associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination IDs, a set of cast types, or some combination thereof. The method (500) includes transmitting (506) the non- numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to postpone the SL HARQ feedback, and triggering (508) the second UE to transmit the SL HARQ feedback. The method (500) includes receiving (510) the SL HARQ feedback from the second UE.

Description

CONFIGURING SIDELINK HYBRID AUTOMATIC REPEAT REQUEST FEEDBACK

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States Patent Application Serial Number 63/305,591 entitled “CONFIGURING SIDELINK HYBRID AUTOMATIC REPEAT REQUEST FEEDBACK” and fded on February 1, 2022 for Karthikeyan Ganesan et al., which is incorporated herein by reference in its entirety.

FIELD

[0002] The subject matter disclosed herein relates generally to wireless communications and more particularly relates to configuring sidelink hybrid automatic repeat request feedback.

BACKGROUND

[0003] In certain wireless communications networks, sidelink (“SL”) hybrid automatic repeat request (“HARQ”) feedback may be reported. In such networks, the HARQ feedback may be delayed.

BRIEF SUMMARY

[0004] Methods for configuring sidelink hybrid automatic repeat request feedback are disclosed. Apparatuses and systems also perform the functions of the methods. One embodiment of a method includes determining, at a first user equipment (UE), to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE. In some embodiments, the method includes configuring sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof. In certain embodiments, the method includes transmitting the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to postpone the SL HARQ feedback. In some embodiments, the method includes triggering the second UE to transmit the SL HARQ feedback. In various embodiments, the method includes receiving the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non-numerical HARQ feedback indicator.

[0005] One apparatus for configuring sidelink hybrid automatic repeat request feedback includes a first user equipment. In some embodiments, the apparatus includes a processor that: determines to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE; and configures sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof. In various embodiments, the apparatus includes a transmitter that: transmits the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to generate the SL HARQ feedback; and triggers the second UE to transmit the SL HARQ feedback. In certain embodiments, the apparatus includes a receiver that receives the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non-numerical HARQ feedback indicator.

[0006] Another embodiment of a method for configuring sidelink hybrid automatic repeat request feedback includes receiving, at a second UE, a non-numerical HARQ feedback indicator from a first UE in sidelink control information (SCI) based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof, the received non-numerical HARQ feedback indicator triggering the second UE to postpone SL HARQ feedback. In certain embodiments, the method includes receiving a trigger from the first UE in SCI triggering the second UE to transmit the SL HARQ feedback. In some embodiments, the method includes transmitting the SL HARQ feedback from the first UE in response to receiving the trigger.

[0007] Another apparatus for configuring sidelink hybrid automatic repeat request feedback includes a second UE. In some embodiments, the apparatus includes a receiver that: receives a non-numerical HARQ feedback indicator from a first UE in sidelink control information (SCI) based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof, the received non-numerical HARQ feedback indicator triggering the second UE to postpone SL HARQ feedback; and receives a trigger from the first UE in SCI triggering the second UE to transmit the SL HARQ feedback. In various embodiments, the apparatus includes a transmitter that transmits the SL HARQ feedback from the first UE in response to receiving the trigger.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: [0009] Figure 1 is a schematic block diagram illustrating one embodiment of a wireless communication system for configuring sidelink hybrid automatic repeat request feedback;

[0010] Figure 2 is a schematic block diagram illustrating one embodiment of an apparatus that may be used for configuring sidelink hybrid automatic repeat request feedback;

[0011] Figure 3 is a schematic block diagram illustrating one embodiment of an apparatus that may be used for configuring sidelink hybrid automatic repeat request feedback;

[0012] Figure 4 is a schematic block diagram illustrating one embodiment of a system for non-numerical HARQ feedback;

[0013] Figure 5 is a flow chart diagram illustrating one embodiment of a method for configuring sidelink hybrid automatic repeat request feedback; and

[0014] Figure 6 is a flow chart diagram illustrating another embodiment of a method for configuring sidelink hybrid automatic repeat request feedback.

DETAILED DESCRIPTION

[0015] As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, and/or program code, referred hereafter as code. The storage devices may be tangible, non-transitory, and/or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

[0016] Certain of the functional units described in this specification may be labeled as modules, in order to more particularly emphasize their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom very-large-scale integration (“VLSI”) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

[0017] Modules may also be implemented in code and/or software for execution by various types of processors. An identified module of code may, for instance, include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may include disparate instructions stored in different locations which, when joined logically together, include the module and achieve the stated purpose for the module.

[0018] Indeed, a module of code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different computer readable storage devices. Where a module or portions of a module are implemented in software, the software portions are stored on one or more computer readable storage devices. As used herein, a set may include one or more elements.

[0019] Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0020] More specific examples (a non-exhaustive list) of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (“RAM”), a read-only memory (“ROM”), an erasable programmable read-only memory (“EPROM” or Flash memory), a portable compact disc readonly memory (“CD-ROM”), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0021] Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or the like, and/or machine languages such as assembly languages. The code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (“LAN”) or a wide area network (“WAN”), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0022] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.

[0023] Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment.

[0024] Aspects of the embodiments are described below with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and program products according to embodiments. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by code. The code may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

[0025] The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function/act specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

[0026] The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

[0027] The schematic flowchart diagrams and/or schematic block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods and program products according to various embodiments. In this regard, each block in the schematic flowchart diagrams and/or schematic block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing the specified logical function(s).

[0028] It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated Figures.

[0029] Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and code.

[0030] The description of elements in each figure may refer to elements of proceeding figures. Like numbers refer to like elements in all figures, including alternate embodiments of like elements.

[0031] Figure 1 depicts an embodiment of a wireless communication system 100 for configuring sidelink hybrid automatic repeat request feedback. In one embodiment, the wireless communication system 100 includes remote units 102 and network units 104. Even though a specific number of remote units 102 and network units 104 are depicted in Figure 1, one of skill in the art will recognize that any number of remote units 102 and network units 104 may be included in the wireless communication system 100.

[0032] In one embodiment, the remote units 102 may include computing devices, such as desktop computers, laptop computers, personal digital assistants (“PDAs”), tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle on-board computers, network devices (e.g., routers, switches, modems), aerial vehicles, drones, or the like. In some embodiments, the remote units 102 include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the remote units 102 may be referred to as subscriber units, mobiles, mobile stations, users, terminals, mobile terminals, fixed terminals, subscriber stations, UE, user terminals, a device, or by other terminology used in the art. The remote units 102 may communicate directly with one or more of the network units 104 via UL communication signals. In certain embodiments, the remote units 102 may communicate directly with other remote units 102 via sidelink communication.

[0033] The network units 104 may be distributed over a geographic region. In certain embodiments, a network unit 104 may also be referred to and/or may include one or more of an access point, an access terminal, a base, a base station, a location server, a core network (“CN”), a radio network entity, a Node-B, an evolved node-B (“eNB”), a 5G node-B (“gNB”), a Home Node-B, a relay node, a device, a core network, an aerial server, a radio access node, an access point (“AP”), new radio (“NR”), a network entity, an access and mobility management function (“AMF”), a unified data management (“UDM”), a unified data repository (“UDR”), a UDM/UDR, a policy control function (“PCF”), a radio access network (“RAN”), a network slice selection function (“NSSF”), an operations, administration, and management (“0AM”), a session management function (“SMF”), a user plane function (“UPF”), an application function, an authentication server function (“AUSF”), security anchor functionality (“SEAF”), trusted non- 3 GPP gateway function (“TNGF”), or by any other terminology used in the art. The network units 104 are generally part of a radio access network that includes one or more controllers communicab ly coupled to one or more corresponding network units 104. The radio access network is generally communicably coupled to one or more core networks, which may be coupled to other networks, like the Internet and public switched telephone networks, among other networks. These and other elements of radio access and core networks are not illustrated but are well known generally by those having ordinary skill in the art. [0034] In one implementation, the wireless communication system 100 is compliant with NR protocols standardized in third generation partnership project (“3GPP”), wherein the network unit 104 transmits using an OFDM modulation scheme on the downlink (“DL”) and the remote units 102 transmit on the uplink (“UL”) using a single -carrier frequency division multiple access (“SC-FDMA”) scheme or an orthogonal frequency division multiplexing (“OFDM”) scheme. More generally, however, the wireless communication system 100 may implement some other open or proprietary communication protocol, for example, WiMAX, institute of electrical and electronics engineers (“IEEE”) 802.11 variants, global system for mobile communications (“GSM”), general packet radio service (“GPRS”), universal mobile telecommunications system (“UMTS”), long term evolution (“LTE”) variants, code division multiple access 2000 (“CDMA2000”), Bluetooth®, ZigBee, Sigfoxx, among other protocols. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

[0035] The network units 104 may serve a number of remote units 102 within a serving area, for example, a cell or a cell sector via a wireless communication link. The network units 104 transmit DL communication signals to serve the remote units 102 in the time, frequency, and/or spatial domain.

[0036] In various embodiments, a remote unit 102 may determine, at a first user equipment (UE), to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE. In some embodiments, the remote unit 102 may configure sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof. In certain embodiments, the remote unit 102 may transmit the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to postpone the SL HARQ feedback. In some embodiments, the remote unit 102 may trigger the second UE to transmit the SL HARQ feedback. In various embodiments, the remote unit 102 may receive the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non-numerical HARQ feedback indicator. Accordingly, the remote unit 102 may be used for configuring sidelink hybrid automatic repeat request feedback.

[0037] In certain embodiments, a remote unit 102 may receive, at a second UE, a non- numerical HARQ feedback indicator from a first UE in sidelink control information (SCI) based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof, the received non-numerical HARQ feedback indicator triggering the second UE to postpone SL HARQ feedback. In certain embodiments, the remote unit 102 may receive a trigger from the first UE in SCI triggering the second UE to transmit the SL HARQ feedback. In some embodiments, the remote unit 102 may transmit the SL HARQ feedback from the first UE in response to receiving the trigger. Accordingly, the remote unit 102 may be used for configuring sidelink hybrid automatic repeat request feedback.

[0038] Figure 2 depicts one embodiment of an apparatus 200 that may be used for configuring sidelink hybrid automatic repeat request feedback. The apparatus 200 includes one embodiment of the remote unit 102. Furthermore, the remote unit 102 may include a processor 202, a memory 204, an input device 206, a display 208, a transmitter 210, and a receiver 212. In some embodiments, the input device 206 and the display 208 are combined into a single device, such as a touchscreen. In certain embodiments, the remote unit 102 may not include any input device 206 and/or display 208. In various embodiments, the remote unit 102 may include one or more of the processor 202, the memory 204, the transmitter 210, and the receiver 212, and may not include the input device 206 and/or the display 208.

[0039] The processor 202, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor 202 may be a microcontroller, a microprocessor, a central processing unit (“CPU”), a graphics processing unit (“GPU”), an auxiliary processing unit, a field programmable gate array (“FPGA”), or similar programmable controller. In some embodiments, the processor 202 executes instructions stored in the memory 204 to perform the methods and routines described herein. The processor 202 is communicatively coupled to the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212.

[0040] The memory 204, in one embodiment, is a computer readable storage medium. In some embodiments, the memory 204 includes volatile computer storage media. For example, the memory 204 may include a RAM, including dynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or static RAM (“SRAM”). In some embodiments, the memory 204 includes non-volatile computer storage media. For example, the memory 204 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 204 includes both volatile and non-volatile computer storage media. In some embodiments, the memory 204 also stores program code and related data, such as an operating system or other controller algorithms operating on the remote unit 102.

[0041] The input device 206, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device 206 may be integrated with the display 208, for example, as a touchscreen or similar touch-sensitive display. In some embodiments, the input device 206 includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device 206 includes two or more different devices, such as a keyboard and a touch panel.

[0042] The display 208, in one embodiment, may include any known electronically controllable display or display device. The display 208 may be designed to output visual, audible, and/or haptic signals. In some embodiments, the display 208 includes an electronic display capable of outputting visual data to a user. For example, the display 208 may include, but is not limited to, a liquid crystal display (“LCD”), a light emitting diode (“LED”) display, an organic light emitting diode (“OLED”) display, a projector, or similar display device capable of outputting images, text, or the like to a user. As another, non-limiting, example, the display 208 may include a wearable display such as a smart watch, smart glasses, a heads-up display, or the like. Further, the display 208 may be a component of a smart phone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like.

[0043] In certain embodiments, the display 208 includes one or more speakers for producing sound. For example, the display 208 may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the display 208 includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all or portions of the display 208 may be integrated with the input device 206. For example, the input device 206 and display 208 may form a touchscreen or similar touch-sensitive display. In other embodiments, the display 208 may be located near the input device 206.

[0044] In certain embodiments, the processor 202: determines to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE; and configures sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof. In various embodiments, the transmitter 210: transmits the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to generate the SL HARQ feedback; and triggers the second UE to transmit the SL HARQ feedback. In certain embodiments, the receiver 212 receives the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non-numerical HARQ feedback indicator.

[0045] In some embodiments, the receiver 212: receives a non-numerical HARQ feedback indicator from a first UE in sidelink control information (SCI) based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof, the received non-numerical HARQ feedback indicator triggering the second UE to postpone SL HARQ feedback; and receives a trigger from the first UE in SCI triggering the second UE to transmit the SL HARQ feedback. In various embodiments, the transmitter 210 transmits the SL HARQ feedback from the first UE in response to receiving the trigger.

[0046] Although only one transmitter 210 and one receiver 212 are illustrated, the remote unit 102 may have any suitable number of transmitters 210 and receivers 212. The transmitter 210 and the receiver 212 may be any suitable type of transmitters and receivers. In one embodiment, the transmitter 210 and the receiver 212 may be part of a transceiver.

[0047] Figure 3 depicts one embodiment of an apparatus 300 that may be used for configuring side link hybrid automatic repeat request feedback. The apparatus 300 includes one embodiment of the network unit 104. Furthermore, the network unit 104 may include a processor 302, a memory 304, an input device 306, a display 308, a transmitter 310, and a receiver 312. As may be appreciated, the processor 302, the memory 304, the input device 306, the display 308, the transmitter 310, and the receiver 312 may be substantially similar to the processor 202, the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212 of the remote unit 102, respectively.

[0048] In certain embodiments, sidelink unlicensed operation may be used. In some embodiments, a new radio (“NR”) unlicensed (“U”) (“NR-U”) hybrid automatic repeat request (“HARQ”) feedback may be enhanced to counter a delay due to listen-before-talk (“LBT”) failure handling for transmitting a HARQ feedback report. In various embodiments, there may be a non- numerical value as feedback timing is used which may postpone transmission of the generated HARQ feedback while a subsequent transmission of a numerical value as part of a downlink (“DL”) downlink control information (“DCI”) triggers the transmission of previously generated HARQ feedback for those HARQ processes where the non-numerical value is indicated.

[0049] In some embodiments, sidelink HARQ feedback reporting may be delayed because of a channel occupancy limitation and a delay in the sidelink HARQ feedback reporting to a transmit (“TX”) UE may affect the reporting of SL HARQ feedback to a gNB. Hence, a sidelink HARQ feedback procedure may require enhancement considering a non-numerical value as feedback timing and reporting of sidelink HARQ feedback reporting to a gNB for unlicensed SL. [0050] In certain embodiments, for one-shot HARQ feedback: new data indicator (“NDI”) can be configured to be part of one-shot HARQ feedback. If NDI is configured: 1) the latest NDI value detected by the UE is reported along with HARQ-ACK for the corresponding HARQ process ID - the UE assumes NDI=0 if there is no prior NDI value for the HARQ process; and/or 2) NDI is included for each TB. IfNDI is not configured: 1) NDI value is not reported along with HARQ- ACK for the corresponding physical downlink shared channel (“PDSCH”); and/or 2) UE is expected to reset HARQ-ACK state (as discontinuous transmission (“DTX”) or nonacknowledgement (“NACK”)) for a HARQ process ID once acknowledgement (“ACK”) is reported for the same HARQ process ID in the previous feedback. In some embodiments, CBG- based HARQ-ACK or TB-based HARQ-ACK can be configured to be part of the one-shot HARQ feedback for the CCs configured with a code block group (“CBG”). It should be noted that for any HARQ ID that is scheduled after the last determined PDSCH for which ACK/NACK decoding result is reported, the UE does not consider this PDSCH for one-shot HARQ codebook composition.

[0051] In various embodiments, in a one-shot codebook, the NDI follows the HARQ-ACK information for each TB. In certain embodiments, in the one-shot codebook, the ordering of information for HARQ-ACK and NDI is as follows: 1) CBG index; 2) TB index; 3) HARQ process ID; and/or 4) serving cell index.

[0052] In some embodiments, for a downlink control information (“DCI”) requesting one- shot HARQ-ACK feedback without scheduling PDSCH, reuse the minimum processing latency for SPS release DCI. In various embodiments, an intended behavior according to NR-U agreements is commonly understood: 1) Type-3 CB can be triggered and reported when no DCI indicated a NNK1 value; 2) Type-3 CB can report HARQ-ACK information for a PDSCH scheduled with NNK1 when UE is configured with type-1 CB; and/or 3) Type-1 CB cannot report HARQ-ACK information for a PDSCH scheduled with NNK1.

[0053] In certain embodiments, if a user equipment (“UE”) is provided pdsch-HARQ- ACK-OneShotFeedback, the UE determines 8Q ^CK, O^^CK, OOACK-I HARQ-ACK information bits, for a total number of O_ACK HARQ-ACK information bits, of a Type-3 HARQ-ACK codebook according to the following procedure, with the following: 1) set lV_c°i_ls to the number of configured serving cells; 2) set /V| A_RQ _C to the value of nrofHARQ-ProcessesForPDSCH for serving cell c, if provided; else, set N_{RAR C} = 8; 3) set

_c to the value of maxNrofCodeWordsScheduledByDCI for serving cell c if harq-ACK-SpatialBundlingPUCCH is provided and NDI_{[ [MU}^ = 0, or if harq- ACK-SpatialBundlingPUCCH is not provided, or if maxCodeBlockGroupsPerTransportBlock is provided for serving cell c else, set iV^_c = 1; 4) set

to the number of HARQ-ACK information bits per transport block (“TB”) for physical downlink shared channel (“PDSCH”) receptions on serving cell c if maxCodeBlockGroupsPerTransportBlock is provided for serving cell c and pdsch-HARQ-ACK-OneShotFeedbackCBG is provided; else, set ^HARQ-ACK C ⁼

set 1VZ)/_HARQ = 0 if pdsch-HARQ-ACK-OneShotFeedbackNDI is provided; else set 1VZ)/_HARQ = 1 ; 6) set c = 0 - serving cell index; 7) set h = 0 - HARQ process number; 8) set t = 0 - TB index; 9) set g = 0 - CBG index; 10) set j = 0 , while c < iV_c°j_ls , while h < iV_RARQ _c , if

NDI_HAR(1 = 0, If RQ^T-^BACK^XC > 0, While t < N^_c, while

ACK information bit for CBG g of TB t for HARQ process number h of serving cell c, if any;

O else, ^1ACK = Q O , j = j + 1, g = g + 1, end while, ^JACK = NDI value indicated in the DCI format corresponding to the HARQ-ACK information bit(s) for TB t for HARQ process number h on

0 serving cell c, if any; else, ¹ , g = 0, j = j + 1 , t = t + 1, end while, else, while t < mation bit for TB t for HARQ process h of serving cell c, if any;

NDI value indicated in the DCI format corresponding to the

HARQ-ACK information bit(s) for TB t for HARQ process number h on serving cell c, if any; else, , j = j + 1, t = t + 1, end while, end if, t = 0, else, if

> 0, while t < if UE has obtained HARQ-ACK information for TB t for HARQ process number h on serving cell c corresponding to a PDSCH reception and has not reported the HARQ-ACK information corresponding to the PDSCH reception, while g <

⁼ HARQ-ACK information bit for CBG g of TB t for HARQ process number h of serving cell c, j = j + 1, g = 9 + 1, end while, else, while g <

~ ^NACK , j = j + 1, g = g + 1, end while, end if, g = 0, t = t + 1, end while, else, while t < N _{R c}, if UE has obtained HARQ-ACK information for TB t for HARQ process number h on serving cell c corresponding to a PDSCH reception and has not reported the HARQ-ACK information corresponding to the PDSCH

reception, if harq-ACK-SpatialBundlingPUCCH is not provided, ⁷ = HARQ-ACK information bit for TB t for HARQ process h of serving cell c, else,

= binary AND operation of the HARQ-ACK information bits corresponding to first and second transport blocks for HARQ process h of serving cell c. If the UE receives one transport block, the UE assumes ACK for the n second transport block, end if, / = / + 1, t = t + 1, else, ^7ACK =NACK, j = j ' + 1, t = t + 1, end if, end while, end if, t = 0, end if, h = h + 1, end while, h = 0, c = c + 1, end while.

[0054] In some embodiments,

> 1 , when a UE receives a PDSCH with one transport block, the HARQ-ACK information is associated with the first transport block.

[0055] In various embodiments, if a UE receives a subcarrier spacing (“SPS”) PDSCH, or a PDSCH that is scheduled by a DCI format that does not support code block group (“CBG”) based PDSCH receptions for a serving cell c and if maxCodeBlockGroupsPerTransportBlock is provided for serving cell c, and pdsch-HARQ-ACK-OneShotFeedbackCBG is provided, the UE repeats ^HARQ-ACK C ti^mes the HARQ-ACK information for the transport block in the PDSCH.

[0056] In certain embodiments, if a UE detects a DCI format that includes a one-shot HARQ-ACK request field with value 1, the UE determines a physical uplink control channel (“PUCCH”) or a physical uplink shared channel (“PUSCH”) to multiplex a Type-3 HARQ-ACK codebook for transmission in a slot. The UE multiplexes only the Type-3 HARQ-ACK codebook in the PUCCH or the PUSCH for transmission in the slot.

[0057] In some embodiments, if: 1) a UE detects a DCI format that includes a one-shot HARQ-ACK request field with value 1 ; and 2) the cyclic redundancy check (“CRC”) of the DCI is scrambled by a cell radio network temporary identifier (“RNTI”) (“C-RNTI”) or an modulation and coding scheme (“MCS”) C-RNTI (“MCS-C-RNTI”); and 3) resourceAllocation = resourceAllocationTypeO and all bits of the frequency domain resource assignment field in the DCI format are equal to 0; or 4) resourceAllocation = resourceAllocationTypel and all bits of the frequency domain resource assignment field in the DCI format are equal to 1; or 5) resourceAllocation = dynamicSwitch and all bits of the frequency domain resource assignment field in the DCI format are equal to 0 or 1.

[0058] In various embodiments, a DCI format provides a request for a Type-3 HARQ- ACK codebook report and does not schedule a PDSCH reception. The UE is expected to provide HARQ-ACK information in response to the request for the Type-3 HARQ-ACK codebook after N symbols from the last symbol of a physical downlink control channel (“PDCCH”) providing the DCI format, where the value of N for r = 0,1,2 by replacing “SPS PDSCH release” with “DCI format.”

[0059] In certain embodiments, if a UE multiplexes HARQ-ACK information in a PUSCH transmission, the UE generates the HARQ-ACK codebook as described in this clause except that harq-ACK-SpatialBundlingPUCCH is replaced by harq-ACK-SpatialBundlingPUSCH. [0060] In some embodiments, non -numerical feedback (e.g., non -numerical HARQ feedback) handling for sidelink unlicensed spectrum may be used. In various embodiments, a TX UE may indicate a non-numerical HARQ feedback timing if there is no physical sidelink feedback channel (“PSFCH”) resource within the channel occupancy duration or if side link (“SL”) grant in DCI format 3 0 indicates it. Non-numerical feedback (or a non-numerical value) may be added to a possible range of HARQ timing indicator values, and may be used to indicate to a RX UE that the HARQ-ACK feedback for the corresponding PSSCH is postponed until the timing and resource for the HARQ-ACK feedback is provided by a TX UE.

[0061] In certain embodiments, a next SCI scheduling PSSCH with a numerical HARQ feedback timing value may imply transmission of HARQ feedback for HARQ processes associated with a destination ID, a HARQ process of a destination ID, HARQ processes associated with a one or more destination IDs, or HARQ processes associated with a same cast type.

[0062] In some embodiments, a numerical feedback timing may be derived using next SCI scheduling PSSCH with an explicit indicator. In various embodiments, PSFCH resource determination may be made by a UE if an index of a PSFCH resource for a PSFCH transmission by associated PSSCH slots is configured with non-numerical HARQ feedback with that of available PSFCH resources. In certain embodiments, a non-numerical HARQ may be indicated using a mode-1 SL grant using DCI format 3 0 and a content of SL HARQ reporting may be indicated if a TX UE autonomously enables non-numerical HARQ feedback.

[0063] In a first embodiment, there may be non-numerical feedback handling. In the first embodiment, a TX UE may indicate, in a first SCI or in a second SCI non-numerical feedback, as one of the values (e.g., while scheduling corresponding PSSCH transmission for the corresponding HARQ process irrespective of the cast type) to inform receive (“RX”) UEs receiving this sidelink control information (“SCI”) to generate HARQ feedback corresponding to that PSSCH but not to transmit the HARQ feedback for this HARQ process in the next PSFCH resource until a separate trigger for requesting HARQ feedback to be transmitted is received.

[0064] In certain embodiments, one bit in a first SCI field or in a second SCI may be used and, if a non-numerical feedback request is enabled, the corresponding bit in the SCI may be set to ‘ 1’ by the TX UE.

[0065] In some embodiments, non-numerical feedback may be restricted only for a certain cast type (e.g., unicast, groupcast) and/or groupcast HARQ feedback option 1 and/or option2, which may be configured (or preconfigured) in a resource pool or configured with a transmission to a UE. [0066] In various embodiments, non-numerical feedback may be triggered by a TX UE if there is no PSFCH resource occasion or no PSFCH resource satisfying a sl-MinTimeGapPSFCH (e.g., a minimum time gap between PSFCH and associated PSSCH in a unit of slots) for the scheduled PSSCH within its channel occupancy duration.

[0067] In certain embodiments, a next SCI scheduling PSSCH with a numerical HARQ feedback timing value may imply transmission of HARQ feedback according to the following: 1) for HARQ processes associated with a destination ID that was previously indicated with non- numerical HARQ feedback; 2) for a HARQ process and destination ID previously indicated with non-numerical HARQ feedback; 3) for HARQ processes for that destination ID that was previously indicated with non-numerical HARQ feedback; 4) for HARQ processes associated with one or more destination IDs that were previously indicated with non-numerical HARQ feedback; 5) for HARQ processes associated with one or more destination IDs and the same cast type that was previously indicated with non-numerical HARQ feedback; and/or 6) a bitmap containing HARQ process numbers, a cast type, one or more destination IDs, or a combination thereof may be signaled in the next SCI scheduling PSSCH.

[0068] In some embodiments, a next SCI scheduling PSSCH with a numerical HARQ feedback timing value may imply transmission of HARQ feedback request previously signaled with a non-numerical feedback value as follows: 1) a numerical HARQ feedback timing request may be transmitted by disabling a ‘non-numerical feedback’ bit in first SCI or in second SCI; 2) a HARQ feedback timing for PSSCH scheduled with a non-numerical value may be derived by a next SCI scheduling PSSCH with a numerical HARQ feedback timing value - the corresponding numerical HARQ feedback timing need not be signaled in the SCI or an absence of HARQ feedback timing in the SCI may mean that a UE could assume a corresponding numerical HARQ feedback timing provided by a configured K value (e.g., preconfigured K value) in a corresponding resource pool; and/or 3) a corresponding numerical HARQ feedback timing may be indicated in SCI. As an example, a multi-bit field in the first SCI or in the second SCI may indicate multiple HARQ feedback timing and a codepoint in that field may indicate a non-numerical HARQ feedback timing.

[0069] Figure 4 is a schematic block diagram illustrating one embodiment of a system 400 for non-numerical HARQ feedback. The system 400 includes a first COT 402 and a second COT 404. The first COT 402 includes an LBT successful 406 indication followed by non-numerical feedbacks in SCI 408. Moreover, the second COT 404 includes an LBT successful 408 indication followed by numerical feedback triggers 412. [0070] In a second embodiment, there may be PSFCH resource determination. In the second embodiment, a next SCI scheduling PSSCH with a numerical HARQ feedback timing value may imply transmission of a HARQ feedback request being received from a TX U according to the first embodiment, then the UE may start associating N PSSCH transmission slots transmitted using a non-numerical HARQ feedback transmission within a current or previous channel occupancy duration to a slot containing a PSFCH resource in a resource pool satisfying sl- MinTimeGapPSFCH.

[0071] In some embodiments, an association of PSFCH slots corresponding to a PSSCH transmission previously transmitted using a non-numerical HARQ feedback with a current or previous channel occupancy duration may start in an ascending order of a PSSCH time slot and may continue in an ascending order of a PSSCH sub-channel transmitted using non-numerical HARQ feedback.

[0072] In various embodiments, a UE determines an index of a PSFCH resource for a PSFCH transmission with HARQ-ACK information in response to a PSSCH reception scheduled PSFCH with non-numerical feedback based on (P_ID + M_ID)'modR - P RB ,CS , where Pm is a physical layer source ID provided by SCI while signaling the non-numerical HARQ feedback.

[0073] In athird embodiment, there may be afirstmode. The DCI format 3 0 may indicate non-numerical HARQ feedback using one of a code point of a PSFCH to HARQ feedback timing indicator where one of the code points may be configured to represent non-numerical HARQ feedback timing while the corresponding physical uplink control channel (“PUCCH”) resource may not be provided. A TX UE may enable non-numerical HARQ feedback in SCI corresponding to a received SL grant (e.g., DCI format 3 0) and HARQ process from a gNB.

[0074] In various embodiments, a gNB may transmit a trigger to a TX UE by transmitting a next DCI scheduling PSSCH transmission with numerical HARQ feedback timing which implies transmission of HARQ feedback for HARQ processes (e.g., one or more HARQ processes) and corresponding PUCCH resources.

[0075] In certain embodiments, a TX UE may enable numerical HARQ feedback in next SCI scheduling PSSCH corresponding to a received SL grant (e.g., DCI format 3 0).

[0076] In various embodiments, if a TX UE autonomously decides on a non-numerical HARQ feedback request transmission irrespective of a SL grant from a DCI format 3 0 while DCI format contains a PSFCH to HARQ feedback timing indicator and a PUCCH resource indicator, then the TX UE may transmit discontinuous transmission (“DTX”) in the corresponding PUCCH resource if the corresponding PSFCH feedback is not received before that. [0077] In certain embodiments, a new indicator may be transmitted in a PUCCH resource indicating LBT failure or PSFCH not received in sidelink due to non-numerical HARQ feedback timing.

[0078] Figure 5 is a flow chart diagram illustrating one embodiment of a method 500 for configuring sidelink hybrid automatic repeat request feedback. In some embodiments, the method 500 is performed by an apparatus, such as the remote unit 102. In certain embodiments, the method 500 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0079] In various embodiments, the method 500 includes determining 502, at a first user equipment (UE), to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE. In some embodiments, the method 500 includes configuring 504 sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non- numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof. In certain embodiments, the method 500 includes transmitting 506 the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to postpone the SL HARQ feedback. In some embodiments, the method 500 includes triggering 508 the second UE to transmit the SL HARQ feedback. In various embodiments, the method 500 includes receiving 510 the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non-numerical HARQ feedback indicator.

[0080] In certain embodiments, transmitting the non-numerical HARQ feedback timing information comprises transmitting sidelink control information (SCI) indicating the non- numerical HARQ indicator, wherein the non-numerical HARQ indicator is represented as a defined timing value or a bit field with a value of 1. In some embodiments, the method 500 further comprises determining an availability of a PSFCH resource for the sidelink HARQ feedback on the PSFCH during a channel occupancy time, the channel occupancy time satisfying a threshold duration defined by sl-MinTimeGapPSFCH, wherein determining to indicate the non-numerical HARQ feedback indicator is based at least in part on the determined availability of the PSFCH resource for the sidelink HARQ feedback on the PSFCH during the channel occupancy time.

[0081] In various embodiments, the method 500 further comprises deriving numerical HARQ feedback timing based at least in part on sidelink control information (SCI) scheduling a physical sidelink shared channel (PSSCH) with an indicator. In one embodiment, SCI scheduling a PSSCH indicates a subset of the set of HARQ processes, the set of destination IDs, the set of cast types, or some combination thereof associated with the PSSCH scheduled by the non- numerical HARQ indicator. In certain embodiments, the method 500 further comprises transmitting HARQ feedback for HARQ processes associated with a destination ID indicated with the non-numerical HARQ feedback indicator, for a HARQ process and destination ID indicated with the non-numerical HARQ feedback indicator, for HARQ processes associated with at least one destination ID indicated with the non-numerical HARQ feedback indicator, or some combination thereof.

[0082] In some embodiments, a one shot HARQ feedback request is used to request the HARQ feedback via a PSSCH scheduled with the non-numerical HARQ feedback indicator. In various embodiments, the method 500 further comprises receiving a HARQ feedback report for a subset of HARQ processes signaled with the non-numerical HARQ feedback indicator in a first available PSFCH resource without the trigger. In one embodiment, the method 500 further comprises receiving a HARQ feedback report in a next available PSFCH resource using a short control exemption signaling rule.

[0083] In certain embodiments, the method 500 further comprises receiving a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a next SCI field. In some embodiments, the method 500 further comprises receiving a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a MAC CE. In various embodiments, the method 500 further comprises receiving a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator by piggybacking HARQ feedback in a next PSSCH transmission.

[0084] Figure 6 is a flow chart diagram illustrating another embodiment of a method 600 for configuring sidelink hybrid automatic repeat request feedback. In some embodiments, the method 600 is performed by an apparatus, such as the remote unit 102. In certain embodiments, the method 600 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0085] In various embodiments, the method 600 includes receiving 602, at a second UE, a non-numerical HARQ feedback indicator from a first UE in sidelink control information (SCI) based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof, the received non-numerical HARQ feedback indicator triggering the second UE to postpone SL HARQ feedback. In certain embodiments, the method 600 includes receiving 604 a trigger from the first UE in SCI triggering the second UE to transmit the SL HARQ feedback. In some embodiments, the method 600 includes transmitting 606 the SL HARQ feedback from the first UE in response to receiving the trigger.

[0086] In certain embodiments, receiving the non-numerical HARQ feedback timing information comprises receiving sidelink control information (SCI) indicating the non-numerical HARQ indicator, wherein the non-numerical HARQ indicator is represented as a defined timing value or a bit field with a value of 1. In some embodiments, the method 600 further comprises receiving HARQ feedback for HARQ processes associated with a destination ID indicated with the non-numerical HARQ feedback indicator, for a HARQ process and destination ID indicated with the non-numerical HARQ feedback indicator, for HARQ processes associated with at least one destination ID indicated with the non-numerical HARQ feedback indicator, or some combination thereof.

[0087] In various embodiments, the method 600 further comprises transmitting a HARQ feedback report for a subset of HARQ processes signaled with the non-numerical HARQ feedback indicator in a first available PSFCH resource without the trigger. In one embodiment, the method 600 further comprises transmitting a HARQ feedback report in a next available PSFCH resource using a short control exemption signaling rule. In certain embodiments, the method 600 further comprises transmitting a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a next SCI field.

[0088] In some embodiments, the method 600 further comprises transmitting a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a MAC CE. In various embodiments, the method 600 further comprises transmitting a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator by piggybacking HARQ feedback in a next PSSCH transmission.

[0089] In one embodiment, a method of at a first user equipment (UE) comprises determining, at a first user equipment (UE), to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE. In some embodiments, the method includes configuring sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof. In certain embodiments, the method includes transmitting the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non- numerical HARQ feedback indicator triggering the second UE to postpone the SL HARQ feedback. In some embodiments, the method includes triggering the second UE to transmit the SL HARQ feedback. In various embodiments, the method includes receiving the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non-numerical HARQ feedback indicator.

[0090] In certain embodiments, transmitting the non-numerical HARQ feedback timing information comprises transmitting sidelink control information (SCI) indicating the non- numerical HARQ indicator, wherein the non-numerical HARQ indicator is represented as a defined timing value or a bit field with a value of 1.

[0091] In some embodiments, the method further comprises determining an availability of a PSFCH resource for the sidelink HARQ feedback on the PSFCH during a channel occupancy time, the channel occupancy time satisfying a threshold duration defined by sl- MinTimeGapPSFCH, wherein determining to indicate the non-numerical HARQ feedback indicator is based at least in part on the determined availability of the PSFCH resource for the sidelink HARQ feedback on the PSFCH during the channel occupancy time.

[0092] In various embodiments, the method further comprises deriving numerical HARQ feedback timing based at least in part on sidelink control information (SCI) scheduling a physical sidelink shared channel (PSSCH) with an indicator.

[0093] In one embodiment, SCI scheduling a PSSCH indicates a subset of the set of HARQ processes, the set of destination IDs, the set of cast types, or some combination thereof associated with the PSSCH scheduled by the non-numerical HARQ indicator.

[0094] In certain embodiments, the method further comprises transmitting HARQ feedback for HARQ processes associated with a destination ID indicated with the non-numerical HARQ feedback indicator, for a HARQ process and destination ID indicated with the non- numerical HARQ feedback indicator, for HARQ processes associated with at least one destination ID indicated with the non-numerical HARQ feedback indicator, or some combination thereof.

[0095] In some embodiments, a one shot HARQ feedback request is used to request the HARQ feedback via a PSSCH scheduled with the non-numerical HARQ feedback indicator.

[0096] In various embodiments, the method further comprises receiving a HARQ feedback report for a subset of HARQ processes signaled with the non-numerical HARQ feedback indicator in a first available PSFCH resource without the trigger.

[0097] In one embodiment, the method further comprises receiving a HARQ feedback report in a next available PSFCH resource using a short control exemption signaling rule.

[0098] In certain embodiments, the method further comprises receiving a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a next SCI field. [0099] In some embodiments, the method further comprises receiving a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a MAC CE.

[0100] In various embodiments, the method further comprises receiving a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator by piggybacking HARQ feedback in a next PSSCH transmission.

[0101] In one embodiment, an apparatus comprises a first user equipment (UE). The apparatus further includes a processor that: determines to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE; and configures sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof. In various embodiments, the apparatus includes a transmitter that: transmits the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to generate the SL HARQ feedback; and triggers the second UE to transmit the SL HARQ feedback. In certain embodiments, the apparatus includes a receiver that receives the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non- numerical HARQ feedback indicator.

[0102] In certain embodiments, the transmitter transmitting the non-numerical HARQ feedback timing information comprises the transmitter transmitting sidelink control information (SCI) indicating the non-numerical HARQ indicator, wherein the non-numerical HARQ indicator is represented as a defined timing value or a bit field with a value of 1.

[0103] In some embodiments, the processor determines an availability of a PSFCH resource for the sidelink HARQ feedback on the PSFCH during a channel occupancy time, the channel occupancy time satisfying a threshold duration defined by sl-MinTimeGapPSFCH, wherein determining to indicate the non-numerical HARQ feedback indicator is based at least in part on the determined availability of the PSFCH resource for the sidelink HARQ feedback on the PSFCH during the channel occupancy time.

[0104] In various embodiments, the processor derives numerical HARQ feedback timing based at least in part on sidelink control information (SCI) scheduling a physical sidelink shared channel (PSSCH) with an indicator. [0105] In one embodiment, SCI scheduling a PSSCH indicates a subset of the set of HARQ processes, the set of destination IDs, the set of cast types, or some combination thereof associated with the PSSCH scheduled by the non-numerical HARQ indicator.

[0106] In certain embodiments, the transmitter transmits HARQ feedback for HARQ processes associated with a destination ID indicated with the non-numerical HARQ feedback indicator, for a HARQ process and destination ID indicated with the non-numerical HARQ feedback indicator, for HARQ processes associated with at least one destination ID indicated with the non-numerical HARQ feedback indicator, or some combination thereof.

[0107] In some embodiments, a one shot HARQ feedback request is used to request the HARQ feedback via a PSSCH scheduled with the non-numerical HARQ feedback indicator.

[0108] In various embodiments, the receiver receives a HARQ feedback report for a subset of HARQ processes signaled with the non-numerical HARQ feedback indicator in a first available PSFCH resource without the trigger.

[0109] In one embodiment, the receiver receives a HARQ feedback report in a next available PSFCH resource using a short control exemption signaling rule.

[0110] In certain embodiments, the receiver receives a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a next SCI field.

[0111] In some embodiments, the receiver receives a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a MAC CE.

[0112] In various embodiments, the receiver receives a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator by piggybacking HARQ feedback in a next PSSCH transmission.

[0113] In one embodiment, a method of at a second user equipment (UE) comprises receiving, at a second UE, a non-numerical HARQ feedback indicator from a first UE in sidelink control information (SCI) based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof, the received non-numerical HARQ feedback indicator triggering the second UE to postpone SL HARQ feedback. In certain embodiments, the method includes receiving a trigger from the first UE in SCI triggering the second UE to transmit the SL HARQ feedback. In some embodiments, the method includes transmitting the SL HARQ feedback from the first UE in response to receiving the trigger.

[0114] In certain embodiments, receiving the non-numerical HARQ feedback timing information comprises receiving sidelink control information (SCI) indicating the non-numerical HARQ indicator, wherein the non-numerical HARQ indicator is represented as a defined timing value or a bit field with a value of 1.

[0115] In some embodiments, the method further comprises receiving HARQ feedback for HARQ processes associated with a destination ID indicated with the non-numerical HARQ feedback indicator, for a HARQ process and destination ID indicated with the non-numerical HARQ feedback indicator, for HARQ processes associated with at least one destination ID indicated with the non-numerical HARQ feedback indicator, or some combination thereof.

[0116] In various embodiments, the method further comprises transmitting a HARQ feedback report for a subset of HARQ processes signaled with the non-numerical HARQ feedback indicator in a first available PSFCH resource without the trigger.

[0117] In one embodiment, the method further comprises transmitting a HARQ feedback report in a next available PSFCH resource using a short control exemption signaling rule.

[0118] In certain embodiments, the method further comprises transmitting a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a next SCI field.

[0119] In some embodiments, the method further comprises transmitting a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a MAC CE.

[0120] In various embodiments, the method further comprises transmitting a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator by piggybacking HARQ feedback in a next PSSCH transmission.

[0121] In one embodiment, an apparatus comprises a second user equipment (UE). The apparatus further comprises a receiver that: receives a non-numerical HARQ feedback indicator from a first UE in sidelink control information (SCI) based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof, the received non-numerical HARQ feedback indicator triggering the second UE to postpone SL HARQ feedback; and receives a trigger from the first UE in SCI triggering the second UE to transmit the SL HARQ feedback. In various embodiments, the apparatus includes a transmitter that transmits the SL HARQ feedback from the first UE in response to receiving the trigger.

[0122] In certain embodiments, the receiver receiving the non-numerical HARQ feedback timing information comprises the receiver receiving sidelink control information (SCI) indicating the non-numerical HARQ indicator, wherein the non-numerical HARQ indicator is represented as a defined timing value or a bit field with a value of 1. [0123] In some embodiments, the receiver receives HARQ feedback for HARQ processes associated with a destination ID indicated with the non-numerical HARQ feedback indicator, for a HARQ process and destination ID indicated with the non-numerical HARQ feedback indicator, for HARQ processes associated with at least one destination ID indicated with the non-numerical HARQ feedback indicator, or some combination thereof.

[0124] In various embodiments, the transmitter transmits a HARQ feedback report for a subset of HARQ processes signaled with the non-numerical HARQ feedback indicator in a first available PSFCH resource without the trigger.

[0125] In one embodiment, the transmitter transmits a HARQ feedback report in a next available PSFCH resource using a short control exemption signaling rule.

[0126] In certain embodiments, the transmitter transmits a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a next SCI field.

[0127] In some embodiments, the transmitter transmits a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a MAC CE.

[0128] In various embodiments, the transmitter transmits a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator by piggybacking HARQ feedback in a next PSSCH transmission.

[0129] Embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

1 . An apparatus comprising a first user equipment (UE), the apparatus further comprising: a processor that: determines to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE; and configures sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof; a transmitter that: transmits the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to generate the SL HARQ feedback; and triggers the second UE to transmit the SL HARQ feedback; and a receiver that receives the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non-numerical HARQ feedback indicator.

2. The apparatus of claim 1, wherein the transmitter transmitting the non-numerical HARQ feedback timing information comprises the transmitter transmitting sidelink control information (SCI) indicating the non-numerical HARQ indicator, wherein the non- numerical HARQ indicator is represented as a defined timing value or a bit field with a value of 1.

3. The apparatus of claim 1, wherein the processor determines an availability of a PSFCH resource for the sidelink HARQ feedback on the PSFCH during a channel occupancy time, the channel occupancy time satisfying a threshold duration defined by sl- MinTimeGapPSFCH, wherein determining to indicate the non-numerical HARQ feedback indicator is based at least in part on the determined availability of the PSFCH resource for the sidelink HARQ feedback on the PSFCH during the channel occupancy time.

Claims

The apparatus of claim 1, wherein the processor derives numerical HARQ feedback timing based at least in part on sidelink control information (SCI) scheduling a physical sidelink shared channel (PSSCH) with an indicator. The apparatus of claim 1, wherein SCI scheduling a PSSCH indicates a subset of the set of HARQ processes, the set of destination IDs, the set of cast types, or some combination thereof associated with the PSSCH scheduled by the non-numerical HARQ indicator. The apparatus of claim 1, wherein the transmitter transmits HARQ feedback for HARQ processes associated with a destination ID indicated with the non-numerical HARQ feedback indicator, for a HARQ process and destination ID indicated with the non- numerical HARQ feedback indicator, for HARQ processes associated with at least one destination ID indicated with the non-numerical HARQ feedback indicator, or some combination thereof. The apparatus of claim 1, wherein a one shot HARQ feedback request is used to request the HARQ feedback via a PSSCH scheduled with the non-numerical HARQ feedback indicator. The apparatus of claim 1, wherein the receiver receives a HARQ feedback report for a subset of HARQ processes signaled with the non-numerical HARQ feedback indicator in a first available PSFCH resource without the trigger. The apparatus of claim 1, wherein the receiver receives a HARQ feedback report in a next available PSFCH resource using a short control exemption signaling rule. The apparatus of claim 1, wherein the receiver receives a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a next SCI field. The apparatus of claim 1, wherein the receiver receives a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator in a MAC CE. The apparatus of claim 1, wherein the receiver receives a HARQ feedback report for a corresponding PSSCH scheduled with the non-numerical HARQ feedback indicator by piggybacking HARQ feedback in a next PSSCH transmission. A method of at a first user equipment (UE), the method comprising: determining to indicate non-numerical hybrid automatic repeat request (HARQ) feedback indicator to a second UE; configuring sidelink (SL) HARQ feedback on a physical sidelink feedback channel (PSFCH) associated with the non-numerical HARQ feedback indicator based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof; transmitting the non-numerical HARQ feedback indicator to the second UE based at least in part on the configuring, the transmitted non-numerical HARQ feedback indicator triggering the second UE to postpone the SL HARQ feedback; triggering the second UE to transmit the SL HARQ feedback; and receiving the SL HARQ feedback from the second UE for the set of HARQ processes, the set of destination IDs, the set of cast types, or the combination thereof associated with the non-numerical HARQ feedback indicator. An apparatus comprising a second user equipment (UE), the apparatus further comprising: a receiver that: receives a non-numerical HARQ feedback indicator from a first UE in sidelink control information (SCI) based at least in part on a set of HARQ processes, a set of destination identifiers (IDs), a set of cast types, or some combination thereof, the received non-numerical HARQ feedback indicator triggering the second UE to postpone SL HARQ feedback; receives a trigger from the first UE in SCI triggering the second UE to transmit the SL HARQ feedback; and a transmitter that transmits the SL HARQ feedback from the first UE in response to receiving the trigger. The apparatus of claim 14, wherein the receiver receiving the non-numerical HARQ feedback timing information comprises the receiver receiving sidelink control information (SCI) indicating the non-numerical HARQ indicator, wherein the non- numerical HARQ indicator is represented as a defined timing value or a bit field with a value of 1.