Techniques for cross-channel occupancy time hybrid automatic repeat request feedback transmissions for sidelink communications in unlicensed spectrum

Abstract

Techniques for cross-channel occupancy time (COT) hybrid automatic repeat request (HARQ) feedback transmission for sidelink communications in unlicensed spectrum can be performed. In one example, a receiving user equipment (UE) can receive a first transmission from a transmitting UE in a first channel occupancy time (COT). The receiving UE can also determine that a first feedback occasion is after a last slot of the first COT. The receiving UE can also determine one or more feedback configurations. The receiving UE can also transmit, to the transmitting UE, a feedback message in the first feedback occasion or a second feedback occasion based on the one or more feedback configurations, the feedback message indicating a decoding of the first transmission.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to Greek Patent Application No. 20200100717, filed December 8, 2020, and entitled “TECHNIQUES FOR CROSS CHANNEL OCCUPANCY TIME HYBRID AUTOMATIC REPEAT REQUEST FEEDBACK TRANSMISSION FOR SIDELINK COMMUNICATION IN UNLICENSED SPECTRUM,” the contents of which are incorporated herein in its entirety by this reference. TECHNICAL FIELD

[0003] Aspects of the disclosure relate generally to wireless communication, and more particularly, to apparatuses and methods for cross-channel occupancy time (COT) hybrid automatic repeat request (HARQ) feedback transmission for sidelink communication in unlicensed spectrum. BACKGROUND

[0004] Wireless communication networks are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems can be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. For example, a fifth generation (5G) wireless communication technology (which can be referred to as New Radio (NR)) is envisaged to expand and support diverse usage scenarios and applications falling under the umbrella of SUMMARY

[0006] The systems, methods, and devices presented herein each have several innovative aspects, no single aspect of which is solely responsible for the desirable attributes disclosed herein. The following briefly describes some illustrative aspects in order to provide a basic understanding of such aspects. This brief overview is not intended as an extensive overview of all contemplated aspects, nor is it intended to identify key or critical elements of all aspects nor does it delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0007] In one aspect, a method of wireless communication by a receiving user equipment (UE) is provided. The method can include receiving a first transmission from a transmitting UE in a first channel occupancy time (COT). The method can include determining, in response to the reception of the first transmission, that a first feedback occasion is outside of the first COT. The method can include determining, in response to determining that the first feedback occasion is outside of the first COT, one or more feedback configurations. The method can include transmitting, based on the one or more feedback configurations, a feedback message to the transmitting UE in the first feedback occasion or a second feedback occasion, the feedback message indicating a decoding of the first transmission.

[0008] In another aspect, a method of wireless communication by a transmitting UE is provided. The method can include transmitting a first transmission to a receiving UE in a first COT. The method can include receiving, based on one or more feedback configurations, a feedback message from the receiving UE in a feedback occasion after a last slot of the first COT, the feedback message indicating a decoding of the first transmission.

[0009] In other aspects, apparatuses and computer readable media for performing the methods are provided.

[0010] To the accomplishment of the foregoing and related aspects, one or more aspects comprise the features recited in the following description and the appended claims, and the following description and the appended claims together with the drawings make apparent to those skilled in the art the nature of the aspects. The description and drawings are illustrative only of some of the aspects and are not intended to be exhaustive of all aspects. BRIEF DESCRIPTION OF DRAWINGS

[0011] The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which:

[0012] Figure 1 is a schematic diagram illustrating an example of a wireless communication system and access network in accordance with aspects of the present disclosure;

[0013] Figure 2 is an example of a user equipment (UE) according to aspects of the present disclosure; Figure 1 is an example of a user equipment (UE) according to aspects of the present disclosure;

[0014] Figure 3 is an example of a slot format according to aspects of the present disclosure;

[0015] Figure 4 is an example of a series of slot formats according to aspects of the present disclosure;

[0016] Figure 5 is a block diagram of a channel occupancy time (COT) format according to aspects of the present disclosure;

[0017] Figure 6 is a block diagram of a first example feedback technique according to aspects of the present disclosure;

[0018] Figure 7 is a block diagram of a second example feedback technique according to aspects of the present disclosure;

[0019] Figure 8 is a block diagram of a third example feedback technique according to aspects of the present disclosure;

[0020] Figure 9 is a block diagram of a fourth example feedback technique according to aspects of the present disclosure;

[0021] Figure 10 is a block diagram of a channel occupancy time (COT) format according to aspects of the present disclosure; Figure 1 is a flowchart of an example method performed by a receiving user equipment (UE) according to aspects of the present disclosure; and

[0022] Figure 11 is a flowchart of an example method performed by a transmitting UE according to aspects of the present disclosure. Figure 1 DETAILED DESCRIPTION

[0023] The detailed description set forth below, in connection with the appended drawings and embodiments described herinin, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein can 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 can 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 the concepts being described.

[0024] ​Traditionally, new radio (NR) sidelink communications (e.g., NR vehicle-to- everything (V2X) communications) are designed to use licensed spectrum (such as shared cellular bands or dedicated spectrum for intelligent transportation systems (ITS)) for communications. However, in some regions, licensed spectrum can not be guaranteed. In these cases, NR V2X can use unlicensed spectrum shared by other technologies (e.g., Wi-Fi) to gain additional bandwidth not provided by licensed spectrum. However, unlicensed spectrum can be subject to regulatory requirements. One of the requirements includes listen-before-talk (LBT) techniques, which require a device to perform sensing (e.g., listening) before the device can transmit (e.g., talk). In LBT, a device can measure energy in a frequency band, and transmit if the energy is below a threshold. LBT includes different types of rules, including, for example: category (CAT) 2 LBT, which does not include random backoff, and CAT 4 LBT, which includes random backoff with a contention window of variable size. However, the use of LBT can cause uncertainty and increase the time delay for confirming data transmissions.

[0025] The present disclosure provides cross-channel occupancy time (COT), or channel occupancy (CO), mixed automatic repeat request (HARQ) feedback transmission for sidelink communications in unlicensed spectrum, which can improve the success probability of HARQ feedback transmission.

[0026] In more detail, NR V2X sidelink HARQ feedback mechanisms in licensed spectrum can include, for example: a first user equipment (UE1) that transmits a data channel, a second UE (UE2) that receives the transmission and transmits an acknowledgement / negative acknowledgement (ACK / NACK) to indicate whether the data was successfully decoded. HARQ feedback transmission can occur in configured or preconfigured physical sidelink feedback channel (PSFCH) resources, which occur every N slots, where the feedback period N = 1, 2, or 4. For example, N = 1 means a feedback opportunity in every slot (e.g., every slot has resources configured for HARQ feedback transmission), N = 2 means a feedback opportunity in every other slot, and N = 4 means a feedback opportunity in every 4 slots.

[0027] If the HARQ feedback is for ACK / NACK-based groupcast communications, the resources for HARQ feedback transmission corresponding to a physical sidelink shared channel (PSSCH) are determined based on the time and frequency location of the transmission and the transmitter UE identity (ID) and receiver UE ID.

[0028] In current NR V2X, each HARQ feedback can be transmitted in one physical resource block (PRB) in one HARQ feedback occasion. In one example, there can be multiple PSFCH resources corresponding to a PSSCH transmission that are configured. In one example, multiple resources can be used for groupcast ACK / NACK feedback, so different receiving UEs in a group can transmit feedback in different PSFCH resources. In another example, it is possible that multiple transmitting UEs transmit data in the same resource (e.g., data collision) and / or multiple HARQ resource mapping can mitigate HARQ collision.

[0029] In one aspect, NR V2X for licensed spectrum can support autonomous resource allocation (e.g., Mode 2). In this example, a UE can access a channel based on V2X channel sensing by the UE. Specifically, the UE can first identify available resources (e.g., candidate resources) for sidelink transmission by the UE. The UE can then select a resource from the candidate resources for transmission. When transmitting a current transmission, resource selection and reservation in autonomous resource allocation can include reservation of up to two future resources in addition to the current resource for transmission by the UE (e.g., for retransmission of a packet). For resource reservation, the UE can select a resource from the candidate resources. When transmitting a PSSCH, a sidelink control indicator (SCI) transmission by the UE can indicate resource allocation for the current transmission. The SCI can also indicate one or more future resources that can be used by the UE to perform retransmission or transmit a different data packet. In some examples, the resource reservations can be linked.

[0030] In one aspect, NR-unlicensed (NR-U) can specify a Type 1 or Type 2 channel access type. In Type 1 channel access, a duration of sensing slots that are sensed as idle before a transmission can be random (e.g., CAT 4 LBT). In one example, channel access by Type 1 channel access can include channel sensing or energy detection performed in a random number of sensing slots. In Type 2 channel access, a duration of sensing slots that are sensed as idle before a transmission is determined based on: Type 2A with a sensing duration of 25 microseconds (ps), Type 2B with a sensing duration of 16 ps, or Type 2C without a sensing duration (e.g., which can be applied when a gap between two transmissions is not greater than 16 us). Generally, Type 2 channel access requires fewer operations than Type 1 channel access.

[0031] In another aspect of NR-U, a base station can initiate a channel occupancy time (COT) or channel occupancy (CO) based on Type 1 channel access. The base station can share the COT with other UEs such that the UEs can perform Type 2 channel access prior to an intended transmission in the COT, and if the Type 2 channel access is successful, the UEs can transmit.

[0032] In an aspect, retransmission based on HARQ feedback can improve system performance. For example, retransmission based on NACK feedback can guarantee that a packet is successfully delivered to an intended receiver. Compared to blind retransmission (e.g., blindly transmitting a packet multiple times without a HARQ feedback mechanism), retransmission based on HARQ feedback can improve spectral efficiency. However, for sidelink communications in unlicensed spectrum, HARQ feedback transmission can be subject to availability of the channel, as unlicensed spectrum is shared with other radio access technologies. Due to uncertain channel availability in unlicensed spectrum, a HARQ feedback transmission that occurs in certain or known time slots (such as a preconfigured HARQ feedback occasion according to a feedback periodicity N and a HARQ feedback processing timeline) can not be guaranteed. For example, a sidelink receiving UE that receives a sidelink data channel transmission in slot n can not be able to transmit a HARQ feedback until slot n+k, where k is a HARQ feedback processing timeline, which can be greater than or equal to 1 slot; however, availability of slot n+k for HARQ feedback can be subject to, for example, LBT. Furthermore, a COT shared by a UE for sidelink communications can have a limit (e.g., 10 milliseconds (ms) / 20 slots).

[0033] Due to HARQ timeline limitations and COT duration limitations, a sidelink data channel transmission in the last one or more slots of a COT can not have the same COT HARQ feedback resources available (e.g., see Figure 4 COT duration). For example, for a PSSCH transmission that occurs in the last few slots of a COT, due to a HARQ processing timeline (e.g., a gap between a PSSCH transmission and a PSFCH transmission), there can not be a HARQ feedback resource available in the same COT for a corresponding HARQ feedback transmission.

[0034] Accordingly, the present disclosure proposes HARQ feedback techniques that can improve availability of a medium for HARQ feedback transmission, while at the same time not requiring a reduction in HARQ feedback processing time of a receiving UE.

[0035] For a UE receiving a sidelink data channel transmission, the receiving UE can determine a first slot (or a first PSFCH occasion) to transmit a HARQ feedback to acknowledge the data channel based on the PSFCH resource configuration and the HARQ timeline. If the receiving UE determines that the first PSFCH occasion is within the same active COT in which the sidelink data channel has been received, the receiving UE can perform a HARQ feedback transmission after a regular HARQ feedback transmission procedure (e.g., perform a Type 2 channel access for the HARQ feedback transmission).

[0036] However, if the receiving UE determines that the first PSFCH occasion is outside of the first COT (e.g., in a slot of the first COT, but the first COT is no longer active in that slot due to the COT duration limit (e.g., the first COT has been released at or before that slot); or in a slot after the last slot of the first COT), the UE can transmit the HARQ feedback based on four options. In Option 1, the receiving UE can determine that the first PSFCH occasion is in a slot of another active COT, which is initiated by the receiving UE, the UE transmitting the PSSCH, or another UE. In Option 1, the receiving UE can transmit the HARQ feedback in the determined HARQ occasion (e.g., after a successful Type 2 channel access). In Option 2, the receiving UE can determine that there is a second COT that is active and adjacent to the first COT. In Option 2, the receiving UE can determine a second PSFCH occasion in the second COT to transmit the HARQ feedback (e.g., the second PSFCH occasion can be the same or different from the first PSFCH occasion). In Option 3, the receiving UE can perform a Type 1 channel access before the first PSFCH occasion, and if the receiving UE successfully proceeds with the Type 1 channel access (i.e., the Type 1 channel access indicates a clear channel for transmission), transmit the HARQ feedback in the first PSFCH occasion. In Option 4, the receiving UE can determine that a total number of transmissions of PSFCH during a time window is less than a threshold value, and / or a total duration of the transmissions of PSFCH during the time window is less than a threshold value, and the receiving UE can transmit the HARQ feedback in the first PSFCH occasion.

[0037] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the particular application and design constraints imposed on the overall system.

[0038] By way of example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system can execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0039] Accordingly, in one or more example embodiments, the functions described can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), compact disk ROM (CD-ROM) or other optical disk storage, magnetic disk storage or other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

[0040] Turning now to the figures, examples of systems, apparatuses, and methods in accordance with aspects of the present disclosure are depicted. It will be understood that aspects of the figures can not be drawn to scale and that, for purposes of illustration and explanation, they are drawn to facilitate understanding.

[0041] Figure 1 FIG. 1 is a schematic diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system, which can also be referred to as a wireless wide area network (WWAN) includes at least one base station 105, UEs 110, an evolved packet core (EPC) 160, and a 5G core (5GC) 190. The base stations 105 can include macro cells (high power cellular base stations) and / or small cells (low power cellular base stations). The macro cells can include base stations. The small cells can include femtocells, picocells, and microcells.

[0042] In some implementations, the UE 110 can include a modem 140 and / or a sidelink HARQ component 142 for channel access for sidelink HARQ feedback transmissions in unlicensed spectrum.

[0043] The base stations 105 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 through backhaul links 132 (e.g., SI, X2, Internet Protocol (IP), or flex interfaces). The base stations 105 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) can interface with the 5GC 190 through backhaul links 134 (e.g., SI, X2, Internet Protocol (IP), or flex interfaces). In addition to other functions, the base stations 105 can perform one or more of the following functions: transport of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 105 can communicate with each other directly or indirectly (e.g., through the EPC 160 or 5GC 190) over backhaul links 134. The backhaul links 132, 134 can be wired or wireless.

[0044] The base stations 105 can wirelessly communicate with the UEs 110. Each of the base stations 105 can provide communication coverage for a respective geographic coverage area 130. There can be overlapping geographic coverage areas 130. For example, a small cell 105' can have a coverage area 130' that overlaps with one or more macro cells 105. A network that includes both small cell and macro cells can be known as a heterogeneous network. A heterogeneous network can also include Home Evolved Node Bs (eNBs) (HeNBs), which can provide service to a restricted group known as a closed subscriber group (CSG). The communication links 120 between the base stations 105 and the UEs 110 can include uplink (UL) (also referred to as reverse link) transmissions from a UE 110 to a base station 105 and / or downlink (DL) (also referred to as forward link) transmissions from a base station 105 to a UE 110. The communication links 120 can use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication links can be through one or more carriers, and each carrier can be a band of frequency waves having a xThe bandwidth of each carrier allocated to the UE 110 can be statically configured. Alternatively, the bandwidth of each carrier can be dynamically configured. The UE 110 can be configured with multiple carriers, which can be located in the same frequency (e.g., intra-band) or different frequencies (e.g., inter-band). The UE 110 can be configured with one or more component carriers. The component carriers can include a primary component carrier and one or more secondary component carriers. The primary component carrier can be referred to as a primary cell (PCell) and the secondary component carriers can be referred to as secondary cells (SCells). The PCell can provide both UL and DL resources and can support mobility of the UE 110. The SCell can provide additional DL resources.

[0045] Certain UEs 110 can communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 can use the DL / UL WWAN spectrum. The D2D communication link 158 can use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication can be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on IEEE 802.11 standards, LTE, or NR.

[0046] The wireless communications system can also include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 / AP 150 can perform clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

[0047] The small cells 105' can operate in a licensed and / or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cells 105' can employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cells 105' employing NR in an unlicensed frequency spectrum can boost coverage to and / or increase capacity of an access network.

[0048] The base stations 105, whether small cells 105' or large cells (e.g., macro cells), can include an eNB, gNodeB (gNB), or other types of base station. Some base stations, such as gNB 180 can operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and / or near mmW frequencies in communication with the UEs 110. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 can be referred to as an mmW base station. Extremely high frequency (EHF) is part of the radio frequency (RF) in the electromagnetic spectrum. EHF has a range from 30 GHz to 300 GHz and wavelengths

[0049] The EPC 160 can include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 can be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node for the packaging of the signaling between the UEs 110 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 can include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and / or other IP services. The BM-SC 170 can provide functions for MBMS user service provisioning and

[0050] The 5GC 190 can include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 can be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 110 and the 5GC 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to a IP Services 197. The IP Services 197 can include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and / or other IP services.

[0051] The base stations 105 can also be referred to as gNBs, NodeBs, evolved NodeBs (eNBs), access points, base transceiver stations, radio base stations, access nodes, radio transceiver, NodeBs, eNodeBs (eNB), gNBs, Home NodeBs, Home eNodeBs, relays, transceiver functions, basic service sets (BSSs), extended service sets (ESSs), transmission and reception points (TRPs), or some other suitable terminology. The base stations 105 provide wireless access to the UEs 110 for accessing services from the core network 160 or the 5GC 190. Examples of UEs 110 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similar functional device. Some of the UEs 110 can be referred to as IoT devices (e.g., a parking meter, gas pump, toaster, vehicle, heart monitor, etc.). The UEs 110 can also be referred to as a station, a mobile, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0052] Reference Figure 2An example implementation of UE 110 may include a modem 140 having a sidelink HARQ component 142. The modem 140 and / or the sidelink HARQ component 142 of UE 110 may be configured to manage communications with other UEs via cellular networks, Wi-Fi networks, or other wireless and wired networks using licensed and / or unlicensed spectrum.

[0053] In some implementations, UE 110 may include various components, including components such as one or more processors 212 and memory 216 and transceiver 202 that communicate via one or more buses 244, which may cooperate with modem 140 and / or sidelink HARQ component 142 to implement one or more of the functions described herein related to sidelink HARQ transmission. Furthermore, one or more processors 212, modem 140, memory 216, transceiver 202, RF front end 288, and one or more antennas 265 may be configured to support voice and / or data calls (simultaneously or not simultaneously) in one or more radio access technologies. The one or more antennas 265 may include one or more antennas, antenna elements, and / or antenna arrays.

[0054] In one aspect, one or more processors 212 may include a modem 140 using one or more modem processors. Various functions associated with the sidelink HARQ component 142 may be included in the modem 140 and / or processor 212, and in one aspect, may be executed by a single processor, while in other aspects, different functions may be executed by a combination of two or more different processors. For example, in one aspect, one or more processors 212 may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receive device processor, or a transceiver processor associated with transceiver 202. Furthermore, modem 140 may configure UE 110 and processor 212. In other aspects, some features of the one or more processors 212 and / or modem 140 associated with the sidelink HARQ component 142 may be executed by transceiver 202.

[0055] Further, memory 216 can be configured to store data used by the applications 275 and / or local versions of the sidelink HARQ component 142 and / or one or more subcomponents of the sidelink HARQ component 142 executed by at least one processor 212. Memory 216 can include any type of computer-readable medium usable by a computer or at least one processor 212, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, when UE 110 is operating at least one processor 212 to execute the sidelink HARQ component 142 and / or one or more of the subcomponents, memory 216 can be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining the sidelink HARQ component 142 and / or one or more of the subcomponents thereof, and / or data associated therewith.

[0056] Transceiver 202 can include at least one receiver 206 and at least one transmitter 208. Receiver 206 can include hardware, firmware, and / or software code executable by a processor for receiving data, the code including instructions for receiving data and being stored in a memory (e.g., computer-readable medium). Receiver 206 can be, for example, a RF receiving device. In an aspect, receiver 206 can receive signals transmitted by at least one base station 105. Transmitter 208 can include hardware, firmware, and / or software code executable by a processor for transmitting data, the code including instructions for transmitting data and being stored in a memory (e.g., computer-readable medium). A suitable example of transmitter 208 can include, but is not limited to, a RF transmitter.

[0057] Further, in an aspect, UE 110 can include RF front end 288, which can communicate with one or more antennas 265 and transceiver 202 for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station 105 or wireless transmissions transmitted by UE 110. RF front end 288 can be coupled with one or more antennas 265 and can include one or more low-noise amplifiers (LNAs) 290, one or more switches 292, one or more power amplifiers (PAs) 298, and one or more filters 296 for transmitting and receiving RF signals.

[0058] In an aspect, LNA 290 can amplify a received signal at a desired output level. In an aspect, each of the LNA 290 can have a specified minimum and maximum gain values. In an aspect, RF front end 288 can use one or more switches 292 to select a particular LNA 290 and a specified gain value based on a desired gain value for a particular application.

[0059] Further, for example, RF front end 288 can use one or more PA's 298 to amplify a signal for an RF output at a desired output power level. In an aspect, each of the PA's 298 can have a specified minimum and maximum gain values. In an aspect, RF front end 288 can use one or more switches 292 to select a particular PA 298 and a specified gain value based on a desired gain value for a particular application.

[0060] Further, for example, RF front end 288 can use one or more filters 296 to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, individual filters 296 can be used to filter output from individual PA's 298 to produce an output signal for transmission. In an aspect, each filter 296 can be coupled with a particular LNA 290 and / or PA 298. In an aspect, RF front end 288 can use one or more switches 292 to select a transmit or receive path using a specified filter 296, LNA 290, and / or PA 298 based on a configuration specified by transceiver 202 and / or processor 212.

[0061] As such, transceiver 202 can be configured to transmit and receive wireless signals via RF front end 288 through one or more antennas 265. In an aspect, transceiver 202 can be tuned to operate at specified frequencies, such that, for example, UE 110 can communicate with one or more of base stations 105 or one or more cells associated with one or more of base stations 105. In an aspect, for example, modem 140 can configure transceiver 202 to operate at a specified frequency and power level based on a UE configuration of UE 110 and communication protocols used by modem 140.

[0062] In an aspect, modem 140 can be a multi-band multi-mode modem that can process digital data and communicate with transceiver 202 such that digital data is transmitted and received using transceiver 202. In an aspect, modem 140 can be multi-band and configured to support multiple frequency bands for a particular communication protocol. In an aspect, modem 140 can be multi-mode and configured to support multiple operating networks and communication protocols. In an aspect, modem 140 can control one or more components of UE 110 (e.g., RF front end 288, transceiver 202) to implement transmitting and / or receiving signals from a network based on a specified modem configuration. In an aspect, the modem configuration can be based on the mode of modem 140 and the frequency band used. In another aspect, the modem configuration can be based on UE configuration information associated with UE 110 provided by a network (e.g., base station 105).

[0063] Referring to Figure 3 A single slot format 300 for NR V2X communication is provided. In an example, slot format 300 can include 14 symbols including a portion for a physical sidelink control channel (PSCCH) 302 to carry, for example, control signals, a portion for a PSCCH 304 to carry, for example, data signals, one or more gaps 306, and a PSFCH 308 to carry, for example, feedback signals (e.g., HARQ ACK / NACK). Each slot 322 of a plurality of slots 320 can be divided into frequency PRBs 324 or sub-channels; a PSFCH resource in a PSFCH slot can consist of a set of PRBs 324. In NR V2X, one PSFCH can be transmitted using one PRB 324 with a specific code domain resource (cyclic shift (CS)).

[0064] Referring to Figure 4 An example of a series of slots 400 for NR V2X communication is provided. As shown, the series of slots 400 can start at slot n and increase up to n+m slots, where m is an arbitrary integer. As described herein, feedback can be based on a feedback period N, and a processing time of a receiving UE 110 to decode a received transmission. As shown by the series of slots 400, if N=2 (i.e., there is a feedback opportunity every other slot) and k=2 (i.e., the processing time of the receiving UE 110 requires two slots to decode a transmission and process HARQ feedback), feedback opportunities can not occur until every other slot.

[0065] Referring to Figure 5The example COT 500 is depicted as having a duration of 8 time slots (e.g., time slot n - time slot n + 7). However, in other examples, the COT may have a duration of less than or greater than 8 time slots.

[0066] As described in this paper, the feedback period N can be set to different periods, including, for example, N=2, such that the PFSCH timing 308 (or HARQ timing) is every other time slot, as... Figure 5 As shown. As described in this document, due to HARQ timeline constraints and COT duration constraints, sidelink data channel transmissions in the last single or multiple last time slots of the COT may not have the same COT HARQ feedback resources available. For example, if N=2 and k=2 (i.e., at least two time slots are required for receiving UE 110 decoding transmissions and processing HARQ feedback), as Figure 5 As shown, when the PSSCH is transmitted in slot n, the first HARQ timing to satisfy the timeline is slot n+3, so the HARQ feedback for the PSSCH can be transmitted in slot n+3. However, if the PSSCH is transmitted in slot n+6 (or slot n+7), the corresponding HARQ feedback is mapped to slot n+9, which is not included in the same COT because the COT ends at slot n+7. Therefore, this disclosure provides a technique for transmitting HARQ feedback across COTs.

[0067] refer to Figure 6 An example of a first feedback technique 600 is provided (e.g., option 1 above). As shown, two active COTs (first active COT 602 and second active COT 604) may be available. COT 602 and 604 may be examples of COT 500.

[0068] In the first feedback technique 600, the receiving UE 110 can determine that the first PSFCH occasion 612 (e.g., based on the feedback period N and a processing time for the receiving UE 110 to decode the PSSCH transmission, the first available PSFCH to transmit HARQ feedback) is outside of the first active COT 602. For example, the UE can determine that the feedback should be transmitted in slot n+11, which is outside of the first active COT 602 (e.g., the current COT). However, based on the sidelink decoding (e.g., the UE decodes information of the second active COT 604 from the sidelink transmission in slot n+11), the UE realizes that slot n+11 is included in the second active COT 604, so the UE can still transmit the HARQ feedback in slot n+11. In response to the determination, the receiving UE 110 can determine that the first PSFCH occasion 612 in a slot of the second active COT 604 is available to transmit the HARQ feedback 610. The receiving UE 110 can transmit the HARQ feedback 610 (e.g., after a successful Type 2 channel access) in the first PSFCH occasion 612 as feedback to the PSSCH transmission received in slot n+6 or slot n+7 of the first active COT 602. In one example, the second active COT 604 can be initiated by the receiving UE 110 or another UE 110 during channel access. Thus, the receiving UE 110 can transmit the HARQ feedback 610 if the first PSFCH occasion 612 is in the second active COT 604. In one example, the receiving UE 110 can transmit the HARQ feedback 610 if the receiving UE 110 is allowed to transmit (e.g., the receiving UE 110 determines that it can share the second COT 604). For example, the receiving UE 110 can determine that it is allowed to transmit based on the decoded COT information (e.g., from decoding the sidelink transmission in slot n+11) that indicates the COT is a shared COT. In another example, the receiving UE 110 can transmit the HARQ feedback 610 if a channel access (e.g., Type 2 channel access) is successful prior to the HARQ feedback 610 transmission.

[0069] For example, as shown in FIG. 6A, the first active COT 602 ends at slot n+7, and the feedback period n = 4. For a data channel transmission in slot n+6 or slot n+7, the PSFCH occasion 612 is determined to be in slot n+11. The receiving UE 110 can determine that slot n+11 is in the second active COT 604 (which is initiated at slot n+10), so the receiving UE 110 can transmit the HARQ feedback 610 in the determined PSFCH occasion 612. Figure 6

[0070] Referring to FIG. 6B, in the second feedback technique 650, the receiving UE 110 can determine that the first PSFCH occasion 652 (e.g., based on the feedback period N and a processing time for the receiving UE 110 to decode the PSSCH transmission, the first available PSFCH to transmit HARQ feedback) is outside of the first active COT 602. For example, the UE can determine that the feedback should be transmitted in slot n+11, which is outside of the first active COT 602 (e.g., the current COT). However, based on the sidelink decoding (e.g., the UE decodes information of the second active COT 604 from the sidelink transmission in slot n+11), the UE realizes that slot n+11 is included in the second active COT 604, so the UE can still transmit the HARQ feedback in slot n+11. In response to the determination, the receiving UE 110 can determine that the first PSFCH occasion 652 in a slot of the second active COT 604 is available to transmit the HARQ feedback 660. The receiving UE 110 can transmit the HARQ feedback 660 (e.g., after a successful Type 2 channel access) in the first PSFCH occasion 652 as feedback to the PSSCH transmission received in slot n+6 or slot n+7 of the first active COT 602. In one example, the second active COT 604 can be initiated by the receiving UE 110 or another UE 110 during channel access. Thus, the receiving UE 110 can transmit the HARQ feedback 660 if the first PSFCH occasion 652 is in the second active COT 604. In one example, the receiving UE 110 can transmit the HARQ feedback 660 if the receiving UE 110 is allowed to transmit (e.g., the receiving UE 110 determines that it can share the second COT 604). For example, the receiving UE 110 can determine that it is allowed to transmit based on the decoded COT information (e.g., from decoding the sidelink transmission in slot n+11) that indicates the COT is a shared COT. In another example, the receiving UE 110 can transmit the HARQ feedback 660 if a channel access (e.g., Type 2 channel access) is successful prior to the HARQ feedback 660 transmission. Figure 7 ​An example of a second feedback technique 700 is provided (e.g., option 2 above). As shown, two active COTs (first active COT 702 and second active COT 704 (including time slot p-time slot p+7)) may be available. COT 702 and COT 704 may be examples of COT 500.

[0071] In the second feedback technique 700, the receiving UE 110 can determine the PSFCH timing outside the first activity COT 702, and if the second activity COT 704 is adjacent to the first activity COT 702, HARQ feedback 710 can be sent in the second activity COT 704. In one example, the second activity COT 704 can be initiated by the receiving UE 110 or another UE.

[0072] In this technology, "adjacent" may include one or more of the following characteristics: both COTs 702 and 704 are initiated by receiving UE 110 (i.e., the same UE); both COTs 702 and 704 are initiated by two UEs (e.g., receiving UE 110 and a second UE) that are within each other's range threshold (e.g., the distance between COT initiators based on the initiator location indicated by the COT information); the distance to the initiator UE of the second active COT 704 or the initiator UE of both COTs 702 and COT 704 (such as absolute distance (e.g., meters) or RF distance (e.g., reference signal received power (RSRP))) is within a distance threshold; or the gap 714 between the two COTs 702 and COT 704 (e.g., the duration from the end of the first active COT 702 to the start of the second active COT 704) has a duration less than a threshold.

[0073] In one example, such as Figure 7 As shown, the first active COT 702 ends at time slot n+7. For data channel transmission in time slot n+6, the PSFCH timing is determined to be time slot n+11, which is not in the first active COT 702. The receiving UE 110 can determine the existence of a second active COT 704 adjacent to the first active COT 702 based on the characteristics described herein. The receiving UE 702 can determine the second PSFCH timing 712 in the second active COT 704 to send HARQ feedback 710.

[0074] While this example describes a second PSFCH timing 712 that differs from the first PSFCH timing, in another example, the second PSFCH timing 712 may be the same as the first PSFCH timing. In one aspect, the second feedback technique 700 may include Type 2 channel access for HARQ feedback transmissions.

[0075] Referring to Figure 8 , an example of a third feedback technique 800 (e.g., option 3 described above) is provided. As shown, a first active COT 802 can be available. The COT 802 can be an example of the COT 500.

[0076] In the third feedback technique 800, the receiving UE 800 can perform Type 1 channel access (e.g., random backoff within a contention window) prior to the first PSFCH occasion 812 (or HARQ feedback 810) and transmit the HARQ feedback 810 in the first PSFCH occasion 812 if the receiving UE 110 successfully performs Type 1 channel access (e.g., the Type 1 channel access indicates to the receiving UE 110 that the channel is clear for transmission). In one example, the UE can perform Type 1 channel access for the HARQ feedback 810 transmission regardless of whether the PSFCH occasion 812 is in an active COT, and if the Type 1 channel access is successful, the HARQ feedback can be transmitted. In another example, if the PSFCH occasion 812 is not in an active COT, the UE can perform Type 1 channel access for the HARQ feedback transmission; if the Type 1 channel access is successful, the HARQ feedback 810 can be transmitted.

[0077] As one example and as shown in Figure 8 , the first active COT 802 can end at slot n+7. For the data channel transmission in slot n+6, the PSFCH occasion 812 can be determined to be slot n+11. The receiving UE 110 can determine that slot n+11 is not in the first active COT 802 and thus perform Type 1 channel access for the HARQ feedback 810 transmission in slot n+11. If the Type 1 channel access is successful, the receiving UE 110 can transmit the HARQ feedback 810 in slot n+11.

[0078] Referring to Figure 9 , an example of a fourth feedback technique 900 (e.g., option 4 described above) is provided. As shown, a first active COT 902 can be available. The COT 902 can be an example of the COT 500.

[0079] In the fourth feedback technique 900, the receiving UE 110 can determine that the PSFCH occasion 912 is outside of the first active COT 902, and in response to the determination, the receiving UE 110 can determine whether a total number of HARQ feedback 910 and 920 within a time window 914 is less than a transmission number threshold, and / or determine that a total duration of HARQ feedback 910 and 920 in the time window 914 is less than a transmission duration threshold. In this example, the HARQ feedback 910 can represent HARQ feedback transmissions that the receiving UE 110 will transmit, and the HARQ feedback 920 can represent HARQ feedback transmissions that have already been transmitted.

[0080] If one or more thresholds are satisfied, the receiving UE can transmit the HARQ feedback 910 in the first PSFCH occasion 912. In one example, the time window 914 can include a past time window (e.g., a lookback window) set to a determined duration (e.g., 50 ms). In one example, the time window 914 can include the first PSFCH occasion 912, as shown. However, in other examples, the first PSFCH occasion 912 can not be included in the time window 914. Figure 9

[0081] In one example, the total number of HARQ feedback 910 and 920 can include any transmissions that the receiving UE 110 transmits in PSFCH occasions during the time window 914. In one example, the total duration of HARQ feedback 910 and 920 in the time window 914 can include a duration of each HARQ feedback 910 and 920 during the time window 914.

[0082] In one example, the transmission number threshold and the transmission duration threshold can be predetermined (e.g., configured by the receiving UE 110, preconfigured, or predefined). In one example, for a time window 914 of 50 ms, the transmission number threshold can be 50, and for a time window 914 of 50 ms, the transmission duration threshold can be 2.5 ms.

[0083] In one aspect, the fourth feedback technique 900 can include LBT-less PSFCH transmissions. For example, a UE can transmit HARQ feedback based on a type 2-C channel access.

[0084] ​In one aspect, the global PSFCH resource configuration (e.g., PSFCH 308) can be determined based on a period (e.g., feedback period N) and a global slot index (e.g., a slot index representing a physical slot or a slot in a sidelink resource pool). For example, based on the slot index in the sidelink resource pool, the HARQ timeline can be n+2, and the PSFCH slot period can be N=2. In another aspect, the COT-specific PSFCH resource configuration can be based on a period (e.g., feedback period N) and a slot index within the COT. For example, the HARQ timeline can be N+2, and the PSFCH slot period within the COT can be N=4.

[0085] In one aspect, different techniques can be applied based on different conditions determined by the receiving UE 110. For example, if the conditions for the fourth feedback technique 900 cannot be met, the third feedback technique 800 can be applied. In another example, if the conditions for the first feedback technique 600 or the second feedback technique 700 cannot be met, the third feedback technique 800 can be applied. In yet another example, if the conditions for the first feedback technique 600 cannot be met, the second feedback technique 700 can be applied.

[0086] refer to Figure 10 An example of a method 1000 for sidelink HARQ feedback transmission in unlicensed spectrum may be performed by the following: a sidelink HARQ component 142, a modem 140, a transceiver 202, a processor 212, a memory 216, and / or any other component / subcomponent of a receiving UE 110 of a wireless communication network 100.

[0087] At block 1002, method 1000 may include: receiving a first transmission from the transmitting UE in a first COT. For example, the sidelink HARQ component 142, modem 140, transceiver 202, processor 212 and / or memory 216 of UE 110 and / or one or more additional components / subcomponents of UE 110 may be configured to receive the first transmission from the transmitting UE in the first COT or may include a unit for receiving the first transmission from the transmitting UE in the first COT.

[0088] For example, receiving the first transmission at block 702 may include the UE 110's sidelink HARQ component 142, modem 140, transceiver 202, processor 212 and / or memory 216 via antenna 265, RF front end 288 and / or transceiver 202. Figure 6 The first COT 602, Figure 7 The first COT 702, Figure 8 First COT 802 or Figure 9the first feedback occasion 912 is after the last slot n+7 of the first COT 902.

[0089] At block 1004, the method 1000 can include determining, in response to the reception of the first transmission, that the first feedback occasion is outside of the first COT. For example, the sidelink HARQ component 142, the modem 140, the processor 212, and / or the memory 216 of the UE 110 and / or one or more additional components / subcomponents of the UE 110 can be configured to determine that the first feedback occasion is outside of the first COT or can include means for determining that the first feedback occasion is outside of the first COT.

[0090] For example, determining, at block 1004, that the first feedback occasion is outside of the first COT can include determining, by the sidelink HARQ component 142, the modem 140, the processor 212, and / or the memory 216 of the UE 110 that the first feedback occasion 612 is after the last slot n+7 of the first COT 602, Figure 6 the first feedback occasion 612 of the first COT 602, Figure 7 the first feedback occasion (e.g., slot n+11) of the first COT 702, Figure 8 the first feedback occasion 812 of the first COT 802, or Figure 9 the first feedback occasion 912 of the first COT 902.

[0091] In one example, the first feedback occasion can be determined based on the feedback period N and the global slot index (e.g., n - n+7) or the feedback period N and the slot index of the second COT (e.g., n+11 or p - p+7).

[0092] At block 1006, the method 1000 can include determining, in response to determining that the first feedback occasion is after the last slot of the first COT, one or more feedback configurations. For example, the sidelink HARQ component 142, the modem 140, the processor 212, and / or the memory 216 of the UE 110 and / or one or more additional components / subcomponents of the UE 110 can be configured to determine the one or more feedback configurations or can include means for determining the one or more feedback configurations.

[0093] For example, determining the one or more feedback configurations can include determining, by the sidelink HARQ component 142, the modem 140, the processor 212, and / or the memory 216 of the UE 110 that: Figure 6 the first feedback occasion 612 of the first COT 602 is in the active second COT 604; Figure 7 the feedback occasion 712 of the first COT 702 is in an adjacent COT 704; the successful Type 1 channel access is in the first COT 702,Figure 8 The first feedback timing 812 is performed before the first feedback timing; or the total number of feedback transmissions 910 and / or 920 (or the total duration of feedback transmissions 910 and / or 920) is less than a threshold (e.g., a transmission quantity threshold or a transmission duration threshold).

[0094] At block 1008, method 1000 may include: sending a feedback message indicating decoding of the first transmission to the transmitting UE at a first feedback timing or a second feedback timing based on one or more feedback configurations. For example, the sidelink HARQ component 142, modem 140, transceiver 202, processor 212 and / or memory 216 of UE 110 and / or one or more additional components / subcomponents of UE 110 may be configured to send a feedback message indicating decoding of the first transmission to the transmitting UE at a first feedback timing or a second feedback timing based on one or more feedback configurations, or may include units for sending a feedback message indicating decoding of the first transmission to the transmitting UE at a first feedback timing or a second feedback timing based on one or more feedback configurations.

[0095] For example, transmission at block 1008 may include transmission by the UE 110's sidelink HARQ component 142, modem 140, transceiver 202, processor 212 and / or memory 216 via antenna 265, RF front end 288 and / or transceiver 202 at a first feedback timing 612 of the second COT 604 based on one or more feedback configurations (e.g., determining that the second COT 704 is an active COT). Figure 9 The instruction to decode the HARQ feedback 610 for the first transmission in time slot n+6 or time slot n+7 of the first COT 602, based on one or more feedback configurations (e.g., determining that the second COT 704 is adjacent to the first COT 702), is sent to the transmitting UE 110 at the feedback timing 712 (first or second feedback timing) of the second COT 704. Figure 6 The HARQ feedback 710 for decoding the first transmission in time slot n+6 or time slot n+7 of the first COT 702, based on one or more feedback configurations (e.g., determining that Type 1 channel access was successful before the first feedback timing 812), is sent to the transmitting UE 110 at the first feedback timing 812. Figure 7 The instruction to send HARQ feedback 810 for decoding the first transmission in time slot n+6 or time slot n+7 of the first COT 802, or to send to the transmitting UE 110 in the first feedback timing 912 based on one or more feedback configurations (e.g., determining that the total number of feedback transmissions is less than a transmission quantity threshold or determining that the total duration of feedback transmissions is less than a transmission duration threshold). Figure 8HARQ feedback 910 indicating decoding of the first transmission in slot n+6 or slot n+7 of the first COT 902.

[0096] Referring to Figure 9 Examples of the method 1100 for sidelink HARQ feedback transmission in unlicensed spectrum can be executed by a sidelink HARQ component 142, a modem 140, a transceiver 202, a processor 212, a memory 216, and / or any other component / sub-component of the transmitting UE 110 of the wireless communication network 100.

[0097] At block 1102, the method 1100 can include transmitting, to a receiving UE, a first transmission in a first COT. For example, the sidelink HARQ component 142, the modem 140, the transceiver 202, the processor 212, and / or the memory 216 of the UE 110, and / or one or more additional components / subcomponents of the UE 110 can be configured to, or can include means for, transmitting, to a receiving UE, a first transmission in a first COT.

[0098] For example, transmitting the first transmission at block 1102 can include transmitting the data transmission from the transmitting UE 110 to the receiving UE 110 in slot n+6 or slot n+7 of the first COT 602 of FIG. 6, Figure 11 the first COT 702 of FIG. 7, Figure 6 the first COT 802 of FIG. 8, or Figure 7 the first COT 902 of FIG. 9. Figure 8

[0099] At block 1104, the method 1100 can include receiving, from the receiving UE, a feedback message indicating decoding of the first transmission in a feedback occasion after a last slot of the first COT based on the one or more feedback configurations. For example, the sidelink HARQ component 142, the modem 140, the transceiver 202, the processor 212, and / or the memory 216 of the UE 110, and / or one or more additional components / subcomponents of the UE 110 can be configured to, or can include means for, receiving, from the receiving UE, a feedback message indicating decoding of the first transmission in a feedback occasion after a last slot of the first COT based on the one or more feedback configurations.

[0100] ​For example, receiving at block 1104 can include receiving, by the sidelink HARQ component 142, the modem 140, the transceiver 202, the processor 212, and / or the memory 216 of the UE 110, from the receiving UE 110 via the antenna 265, the RF front end 288, and / or the transceiver 202, a HARQ feedback 610 indicating a decode of the first transmission in slot n+6 or slot n+7 of the first COT 602 based on the one or more feedback configurations (e.g., determining that the second COT 704 is an active COT) Figure 9 a HARQ feedback 710 indicating a decode of the first transmission in slot n+6 or slot n+7 of the first COT 702 based on the one or more feedback configurations (e.g., determining that the type 1 channel access is successful prior to the first feedback occasion 812) from the receiving UE 110 in the first feedback occasion 812 Figure 6 a HARQ feedback 710 indicating a decode of the first transmission in slot n+6 or slot n+7 of the first COT 702 based on the one or more feedback configurations (e.g., determining that the type 1 channel access is successful prior to the first feedback occasion 812) from the receiving UE 110 in the first feedback occasion 812 Figure 7 a HARQ feedback 710 indicating a decode of the first transmission in slot n+6 or slot n+7 of the first COT 702 based on the one or more feedback configurations (e.g., determining that the type 1 channel access is successful prior to the first feedback occasion 812) from the receiving UE 110 in the first feedback occasion 812 Figure 8 a HARQ feedback 710 indicating a decode of the first transmission in slot n+6 or slot n+7 of the first COT 702 based on the one or more feedback configurations (e.g., determining that the type 1 channel access is successful prior to the first feedback occasion 812) from the receiving UE 110 in the first feedback occasion 812

[0101] Figure 9 Additional implementations

[0102] An example method of wireless communication by a receiving user equipment (UE), comprising: receiving a first transmission from a transmitting UE in a first channel occupancy time (COT); determining, in response to the receiving of the first transmission, that a first feedback occasion is outside of the first COT; determining, in response to determining that the first feedback occasion is outside of the first COT, one or more feedback configurations; and transmitting, based on the one or more feedback configurations, a feedback message to the transmitting UE in the first feedback occasion or a second feedback occasion, the feedback message indicating a decode of the first transmission.

[0103] In accordance with the example method described above, wherein the determining the one or more feedback configurations comprises determining that the first feedback occasion is in an active second COT, wherein the feedback message is transmitted in the first feedback occasion of the second COT.

[0104] According to one or more of the above example methods, wherein the second COT is initiated by the receiving UE or a second UE.

[0105] According to one or more of the above example methods, further comprising determining that the feedback message can be transmitted in the second COT based on the second COT being shared with one or more second UEs, wherein the feedback message is transmitted further based on the second COT sharing.

[0106] According to one or more of the above example methods, further comprising performing a channel access, wherein the feedback message is transmitted further based on the channel access being successful.

[0107] According to one or more of the above example methods, wherein the determining the one or more feedback configurations comprises determining that a second COT is active and adjacent to the first COT, wherein the feedback message is transmitted in the first feedback occasion of the second COT.

[0108] According to one or more of the above example methods, wherein the second COT is adjacent to the first COT based on the first COT and the second COT being initiated by a same UE comprising the receiving UE or a second UE.

[0109] According to one or more of the above example methods, wherein the second COT is adjacent to the first COT based on the first COT and the second COT being initiated by two UEs within a range threshold of each other, the two UEs comprising the receiving UE or one or more second UEs.

[0110] According to one or more of the above example methods, wherein the second COT is adjacent to the first COT based on an absolute distance or radio frequency (RF) distance from the receiving UE to an initiator UE or an absolute distance or RF distance between initiator UEs of the first COT and the second COT being within a distance threshold, the initiator UEs comprising the receiving UE or one or more second UEs.

[0111] According to one or more of the above example methods, wherein the second COT is adjacent to the first COT based on a gap between the last slot of the first COT and a first slot of the second COT having a duration less than a gap threshold.

[0112] According to one or more of the above example methods, wherein the determining the one or more feedback configurations comprises performing a channel access prior to the transmitting the feedback message, wherein the feedback message is transmitted in the first feedback occasion based further on the channel access being successful, and wherein the channel access comprises a channel sensing or energy detection performed in a random number of sensing slots.

[0113] According to one or more of the above example methods, wherein the first feedback occasion is in an inactive COT.

[0114] According to one or more of the above example methods, wherein the determining the one or more feedback configurations comprises determining one or both of: a total number of feedback messages transmitted during a time window is less than a transmission number threshold or a total duration of the feedback messages during the time window is less than a transmission duration threshold.

[0115] According to one or more of the above example methods, wherein the first feedback occasion is determined based on a feedback period and a global slot index, or wherein the first feedback occasion is determined based on a feedback period and a slot index within a second COT.

[0116] An example apparatus comprising: a memory comprising instructions; and one or more processors communicatively coupled with the memory and configured to execute the instructions to perform one or more of the above example methods.

[0117] An example computer-readable medium (e.g., non-transitory computer- readable medium) having instructions stored therein that, when executed by one or more processors, cause the one or more processors to perform one or more of the above example methods.

[0118] An example apparatus comprising: means for performing one or more of the above example methods.

[0119] A second example method of wireless communication by a transmitting UE, comprising: transmitting, to a receiving UE, a first transmission in a first COT; and receiving, from the receiving UE, a feedback message in a feedback occasion after a last slot of the first COT based on one or more feedback configurations, the feedback message indicating a decoding of the first transmission.

[0120] An example apparatus comprising: a memory comprising instructions; and one or more processors communicatively coupled with the memory and configured to execute the instructions to perform one or more of the above second example methods.

[0121] An example computer-readable medium (e.g., a non-transitory computer-readable medium) has instructions stored therein that, when executed by one or more processors, cause one or more processors to perform one or more example methods of the second example method described above.

[0122] The example apparatus includes: a unit for performing one or more example methods of the second example method described above.

[0123] The specific embodiments described above in conjunction with the accompanying drawings are examples and not intended to represent the only examples that can be implemented or are within the scope of the claims. The term "example" as used in this specification means "serving as an example, instance, or illustration," not "preferred" or "advantageous over other examples." The specific embodiments include detailed descriptions to facilitate understanding of the techniques. However, these techniques can be implemented without these detailed descriptions. For example, changes can be made to the function and arrangement of the elements discussed without departing from the scope of this disclosure. Furthermore, various processes or components can be appropriately omitted, substituted, or added to the various examples. For example, the described methods can be performed in a different order than described, and various steps can be added, omitted, or combined. Moreover, features described with respect to some examples can be combined in other examples. In some cases, well-known structures and apparatuses are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0124] It should be noted that the technologies described herein can be used in various wireless communication networks, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" are often used interchangeably. CDMA systems can implement radio technologies such as CDMA2000 and Universal Terrestrial Radio Access (UTRA). CDMA2000 encompasses the IS-2000, IS-95, and IS-856 standards. IS-2000 versions 0 and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA 2000 1xEV-DO, High-Speed ​​Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. TDMA systems can implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA systems can implement technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash OFDM. TMThe teachings herein can be implemented in / using hardware elements, software elements, or a combination of both. The hardware elements can include devices, logical devices, components, processors, microprocessors, circuits, processor circuits, circuit elements (e.g., transistors, logic gates, and / or resistors), capacitors, inductors, conductors, communication fiber, communication interface, communication ports, or any other hardware- based devices / components. The software elements can include software components, programs, applications, computer programs, application programs, system programs, software development programs, machine programs, operating system or computational / functional applications, depending on how the teachings herein are implemented. The software elements can also include: a protocol stack, security components, security facilities, access components, access facilities, or any other software components / computer programs. The

[0125] Information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on computer-readable media, or any combination thereof.

[0126] The various illustrative blocks and components described in connection with the disclosure herein can be implemented or performed with a specialized programmed processor, such as but not limited to a processor, Digital Signal Processor (DSP), ASIC, 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. The specialized programmed processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, microcontroller, or state machine. A specialized programmed processor can 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).

[0127] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on or transmitted over as one or more instructions or code on a non-transitory computer-readable medium. Other examples and implementations are within the scope and spirit 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 special-purpose processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions can also be physically located at various positions, including being distributed as discrete components or

[0128] Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium can be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0129] The foregoing description of the present disclosure has been provided for the purposes of enabling those of ordinary skill in the art to make and use the disclosure. Various modifications to the disclosure will be readily apparent to those of ordinary skill in the art, and the general principles defined herein can be applied to other variations without departing from the spirit or scope of the disclosure. Further, while the elements of which the described aspects have been described or claimed in singular form, plural forms can be intended unless explicitly stated otherwise. Additionally, all or a portion of any aspect of the disclosure can be used with all or a portion of any other aspect of the disclosure, unless stated otherwise. Thus, the disclosure is not to be limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of wireless communication by a receiving user equipment (UE), comprising: receiving a first transmission from a transmitting UE in a first channel occupancy time (COT); determining, in response to the reception of the first transmission, that a first feedback occasion is outside of the first COT; determining, in response to determining that the first feedback occasion is outside of the first COT, one or more feedback configurations; and transmitting, based on the one or more feedback configurations, a feedback message to the transmitting UE in the first feedback occasion or a second feedback occasion, the feedback message indicating a decoding of the first transmission, wherein the determining the one or more feedback configurations comprises one of: determining that a second COT is active and adjacent to the first COT, wherein the feedback message is transmitted in the first feedback occasion of the second COT; and determining one or both of a total number of feedback messages transmitted during a time window is less than a transmission quantity threshold or a total duration of the feedback messages during the time window is less than a transmission duration threshold, wherein the feedback message is transmitted in the first feedback occasion of the second COT.

2. The method of claim 1, further comprising: determining, based on the second COT being shared with one or more second UEs, that the feedback message can be transmitted in the second COT, wherein the feedback message is transmitted further based on the second COT being shared.

3. The method of claim 1, further comprising: performing a channel access, wherein the feedback message is transmitted further based on the channel access being successful. the second COT is adjacent to the first COT based on the first COT and the second COT being initiated by a same UE comprising the receiving UE or a second UE.

4. The method of claim 1, wherein, the second COT is adjacent to the first COT based on the first COT and the second COT being initiated by two UEs within a range threshold of each other, the two UEs comprising the receiving UE or one or more second UEs.

5. The method of claim 1, wherein, the second COT is adjacent to the first COT based on an absolute distance or radio frequency (RF) distance from the receiving UE to an initiator UE or an absolute distance or RF distance between initiator UEs of the first COT and the second COT being within a distance threshold, the initiator UEs comprising the receiving UE or one or more second UEs.

6. The method of claim 1, wherein, the second COT is adjacent to the first COT based on a gap between a last slot of the first COT and a first slot of the second COT having a duration less than a gap threshold.

7. The method of claim 1, wherein, the determining the one or more feedback configurations comprises:

8. The method of claim 1, wherein, performing a channel access prior to the transmitting the feedback message, wherein the feedback message is transmitted in the first feedback occasion further based on the channel access being successful, and wherein the channel access comprises a channel sensing or energy detection performed in a random number of sensing slots. the first feedback occasion is in an inactive COT.

9. The method of claim 8, wherein, ​ 10. The method of claim 1, wherein, The first feedback occasion is determined based on a feedback period and a global slot index, or wherein the first feedback occasion is determined based on a feedback period and a slot index having a second COT.

11. A method of wireless communication by a transmitting user equipment (UE), comprising: transmitting a first transmission to a receiving UE in a first channel occupancy time (COT); and receiving a feedback message from the receiving UE in a feedback occasion after a last slot of the first COT based on one or more feedback configurations, the feedback message indicating a decoding of the first transmission, wherein: the feedback message is received in a second COT, wherein the second COT is active and adjacent to the first COT; or the feedback message is received in a second COT, wherein one or both of: a total number of feedback messages during a time window is less than a transmission quantity threshold or a total duration of the feedback messages during the time window is less than a transmission duration threshold.

12. A receiving user equipment (UE), comprising: a memory comprising instructions; and one or more processors communicatively coupled with the memory and configured to execute the instructions to: receive a first transmission from a transmitting UE in a first channel occupancy time (COT); determine, in response to the receiving of the first transmission, that a first feedback occasion is outside of the first COT; determine, in response to determining that the first feedback occasion is outside of the first COT, one or more feedback configurations; and transmit a feedback message to the transmitting UE in the first feedback occasion or a second feedback occasion based on the one or more feedback configurations, the feedback message indicating a decoding of the first transmission, wherein the one or more processors are further configured to determine the one or more feedback configurations based on one of: determining that a second COT is active and adjacent to the first COT, wherein the feedback message is transmitted in the first feedback occasion of the second COT; and determining one or both of: a total number of feedback messages transmitted during a time window is less than a transmission quantity threshold or a total duration of the feedback messages during the time window is less than a transmission duration threshold, wherein the feedback message is transmitted in the first feedback occasion of the second COT.

13. The receiving UE of claim 12, wherein, the one or more processors are further configured to execute the instructions to: determine that the feedback message can be transmitted in the second COT based on the second COT being shared with one or more second UEs, wherein the feedback message is transmitted further based on the second COT being shared.

14. The receiving UE of claim 12, wherein, the one or more processors are further configured to execute the instructions to: perform a channel access, wherein the feedback message is transmitted further based on the channel access being successful. the one or more processors are further configured to execute the instructions to: perform a channel access, wherein the feedback message is transmitted further based on the channel access being successful.

15. The receiving UE of claim 12, wherein, the second COT is adjacent to the first COT based on the first COT and the second COT being initiated by a same UE including the receiving UE or a second UE.

16. The receiving UE of claim 12, wherein, the second COT is adjacent to the first COT based on the first COT and the second COT being initiated by two UEs within a range threshold of each other, the two UEs including the receiving UE or one or more second UEs.

17. The receiving UE of claim 12, wherein, the second COT is adjacent to the first COT based on an absolute distance or radio frequency (RF) distance from the receiving UE to an initiator UE or an absolute distance or RF distance between initiator UEs of the first COT and the second COT being within a distance threshold, the initiator UEs including the receiving UE or one or more second UEs.

18. The receiving UE of claim 12, wherein, the second COT is adjacent to the first COT based on a gap between a last slot of the first COT and a first slot of the second COT having a duration less than a gap threshold.

19. The receiving UE of claim 12, wherein, the determining the one or more feedback configurations includes: performing a channel access prior to the transmitting the feedback message, wherein the feedback message is transmitted in the first feedback occasion based further on the channel access being successful, and wherein the channel access includes a channel sensing or energy detection performed in a random number of sensing slots.

20. The receiving UE of claim 19, wherein, the first feedback occasion is in an inactive COT.

21. The receiving UE of claim 12, wherein, the first feedback occasion is determined based on a feedback period and a global slot index, or wherein the first feedback occasion is determined based on a feedback period and a slot index within a second COT.

22. A transmitting user equipment (UE), comprising: a memory including instructions; and one or more processors communicatively coupled with the memory and configured to execute the instructions to: transmit, to a receiving UE, a first transmission in a first channel occupancy time (COT); and receive, from the receiving UE, a feedback message in a feedback occasion after a last slot of the first COT based on one or more feedback configurations, the feedback message indicating a decoding of the first transmission, wherein: the feedback message is received in a second COT, wherein the second COT is active and adjacent to the first COT; or the feedback message is received in a second COT, wherein one or both of a total number of feedback messages during a time window is less than a transmission number threshold or a total duration of the feedback messages during the time window is less than a transmission duration threshold.

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