Managing Sidelink Feedback to the Base Station

Abstract

Various aspects of the present disclosure relate to a user equipment (UE) that acquires a sidelink (SL) grant from a base station, where the SL grant includes a channel occupancy time (COT) for a portion of an unlicensed spectrum that allows the acquiring UE to transmit SL control and data information to a secondary UE. The acquiring UE may also share the COT with the secondary UE, which allows the secondary UE to transmit SL control and data to the acquiring UE or another UE. The acquiring UE performs a clear channel assessment (CCA) on one or more SL resources associated with the SL grant. The UE returns SL hybrid automatic repeat request (HARQ) feedback to the base station based at least in part on the status of the CCA.

Description

[Technical field]

[0001] Related Applications This application claims priority to U.S. patent application Ser. No. 63 / 309,935, filed Feb. 14, 2022, entitled "Managing Sidelink Feedback to a Base Station," the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to wireless communications, and more particularly, to managing sidelink feedback. [Background technology]

[0003] A wireless communication system may include one or more network communication devices, such as base stations, which may be known by another name, eNodeB (eNB), next-generation NodeB (gNB), or other suitable term. Each network communication device, such as a base station, may support wireless communication for one or more user communication devices, which may be known by another name, user equipment (UE), or other suitable term. A wireless communication system may support wireless communication with one or more user communication devices by using resources of the wireless communication system, such as time resources (e.g., symbols, slots, subslots, minislots, aggregate slots, subframes, frames, etc.) or frequency resources (e.g., subcarriers, carriers). Furthermore, a wireless communication system may support wireless communication across various RATs, including third-generation (3G) radio access technologies (RATs), fourth-generation (4G) RATs, fifth-generation (5G) RATs, and other suitable RATs beyond 5G. In some cases, a wireless communication system may be a non-terrestrial based network (NTN), which may support various communication devices for wireless communication in the NTN. For example, NTNs may include network entities onboard non-terrestrial vehicles such as satellites, unmanned aerial vehicles (UAVs), and high altitude platform systems (HAPS), as well as terrestrial network entities such as gateway entities capable of transmitting and receiving over long distances.

[0004] Some wireless communication systems support channel occupation time (COT) sharing between a UE and a base station. Such COT sharing enables a UE or a base station to acquire a COT and share the COT with the other of the UE and the base station. Summary of the Invention [Means for solving the problem]

[0005] The present disclosure relates to a method, apparatus, and system that supports management of sidelink feedback to a base station. A UE can acquire a sidelink (SL) grant from a base station, the grant including a COT for a portion of an unlicensed spectrum that enables the acquiring UE to transmit SL control and data information to a secondary UE. The acquiring UE may also share the COT with the secondary UE, which enables the secondary UE to transmit SL control and data to the acquiring UE or another UE. The acquiring UE performs a clear channel assessment (CCA), such as listen-before-talk (LBT), on one or more SL resources associated with the SL grant. The UE returns SL hybrid automatic repeat request (HARQ) feedback to the base station based at least in part on the status of the CCA. In returning the SL HARQ feedback to the base station, the acquiring UE accounts for a variety of different occurrences, such as CCA failed on one or more SL resources, no physical sidelink feedback channel (PSFCH) was received from the secondary UE before the SL HARQ feedback is to be transmitted to the base station, etc. By using the described techniques, an acquiring UE can provide feedback to the base station based on the status of the CCA that allows the base station to respond appropriately to the feedback and enables the acquiring UE to use SL grants.

[0006] Some implementations of the methods and apparatus described herein may include wireless communication in a device (e.g., a UE), where the device receives first control signaling from a base station indicating a first SL grant having one or more associated SL resources, performs CCA for the one or more associated SL resources, and transmits second control signaling to the base station based at least in part on a status of the CCA.

[0007] In some implementations of the methods and apparatus described herein, the device performs autonomous resource selection to obtain resources for the first SL grant in response to determining that one or more SL resources are not included in the first SL grant or that one or more SL resources are outside of remaining channel occupancy (CO). Additionally or alternatively, the second control signaling includes SL HARQ feedback, and in response to a PSFCH not being received from the second device over the one or more SL resources before a physical uplink control channel (PUCCH) resource is to transmit the SL HARQ feedback to the base station, the device transmits a discontinuous transmission (DTX) in the SL HARQ feedback. Additionally or alternatively, the second control signaling includes SL HARQ feedback, and the device transmits a negative acknowledgment (NACK) in the SL HARQ feedback in response to the PSFCH not being received from the second device over the one or more SL resources before the PUCCH resource is to transmit the SL HARQ feedback to the base station, receives third control signaling from the base station indicating a second SL grant, and ignores the second SL grant in response to the PSFCH being received from the second device over the one or more SL resources after the SL HARQ feedback is transmitted to the base station. Additionally or alternatively, the second control signaling includes a first SL HARQ feedback in the first PUCCH resource indicating a first status of the CCA if the CCA fails for one or more SL resources, or a second SL HARQ feedback in the second PUCCH resource indicating a second status of the CCA if a decoding failure of the SL data occurs. Additionally or alternatively, the first SL grant identifies one or more of an associated SL resource, a COT sharing indicator, or a remaining CO duration. Additionally or alternatively, the second control signaling includes SL HARQ feedback.Additionally or alternatively, the second control signaling includes SL HARQ feedback, and the device, in response to the CCA failing for one or more SL resources, includes an acknowledgement (ACK) in the SL HARQ feedback and performs autonomous resource selection to acquire resources for the first SL grant. Additionally or alternatively, the second control signaling includes SL HARQ feedback, and the device, in response to the CCA failing for one or more SL resources, includes a NACK in the SL HARQ feedback and receives a second SL grant from the base station in response to the SL HARQ feedback. Additionally or alternatively, the device performs Cat 2 LBT as the CCA in response to the first SL grant identifying a COT sharing indicator and one or more associated SL resources. Additionally or alternatively, the device, in response to the first SL grant not identifying one or more associated SL resources, performs autonomous resource selection to acquire resources for the first SL grant within the remaining CO duration. Additionally or alternatively, the second control signaling includes SL HARQ feedback, and the device transmits a NACK in the SL HARQ feedback in response to the PSFCH not being received from the second device over the one or more SL resources before the PUCCH resource is to transmit the SL HARQ feedback to the base station, receives third control signaling from the base station indicating a second SL grant, and transmits a new transmission to the second device over the one or more SL resources associated with the second SL grant in response to the PSFCH not being received from the second device over the one or more SL resources. Additionally or alternatively, the second control signaling includes SL HARQ feedback, and the device transmits SL HARQ feedback in the second PUCCH resource indicating a delay in receiving the PSFCH in response to the PSFCH not being received from the second device over the one or more SL resources before the first PUCCH resource is to transmit the SL HARQ feedback to the base station.Additionally or alternatively, the device receives from the base station a non-numeric SL HARQ feedback indicator, receives a trigger from the base station after receiving the non-numeric SL HARQ feedback indicator to request SL HARQ feedback, and transmits second control signaling to the base station in response to the trigger. Additionally or alternatively, the device receives from the base station an indication of a start of a CO duration for transmission on the one or more associated SL resources as part of the first control signaling, and performs autonomous resource selection to obtain resources for the first SL grant during the time gap indicated by the start of the CO duration.

[0008] Some implementations of the methods and apparatus described herein may include wireless communication in a device (e.g., a base station), where the device sends first control signaling to a UE indicating a first SL grant having one or more associated SL resources and receives second control signaling from the UE based at least in part on a status of a CCA performed by the UE for the one or more associated SL resources.

[0009] In some implementations of the methods and apparatus described herein, the second control signaling includes a first SL HARQ feedback in a first PUCCH resource indicating a first status of the CCA if CCA fails for one or more SL resources, or a second SL HARQ feedback in a second PUCCH resource indicating a second status of the CCA if a decoding failure of the SL data occurs. Additionally or alternatively, the device transmits a non-numeric SL HARQ feedback indicator to the UE, transmits a trigger to the UE after transmitting the non-numeric SL HARQ feedback indicator to request SL HARQ feedback, and receives a second control signaling from the UE in response to the trigger.

[0010] Various aspects of the present disclosure for managing sidelink feedback to a base station are described with reference to the following drawings, in which the same numbers may be used throughout to reference like features and components shown in the drawings. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 illustrates an example wireless communication system that supports management of sidelink feedback to a base station in accordance with an aspect of the present disclosure. [Diagram 2] FIG. 1 illustrates a system that supports management of sidelink feedback to a base station according to an aspect of the present disclosure. [Diagram 3] FIG. 1 illustrates an example of using separate PUCCH resources. [Figure 4] FIG. 1 illustrates an example block diagram of a device (e.g., a UE) that supports management of sidelink feedback to a base station in accordance with an aspect of the present disclosure. [Diagram 5] FIG. 1 illustrates an example block diagram of a device (e.g., a base station) that supports management of sidelink feedback to a base station in accordance with an aspect of the present disclosure. [Figure 6] 1 is a flowchart of a method for supporting management of sidelink feedback to a base station according to an aspect of the present disclosure. [Figure 7] 1 is a flowchart of a method for supporting management of sidelink feedback to a base station according to an aspect of the present disclosure. [Figure 8] 1 is a flowchart of a method for supporting management of sidelink feedback to a base station according to an aspect of the present disclosure. [Figure 9] 1 is a flowchart of a method for supporting management of sidelink feedback to a base station according to an aspect of the present disclosure. [Figure 10] 1 is a flowchart of a method for supporting management of sidelink feedback to a base station according to an aspect of the present disclosure. [Figure 11]1 is a flowchart of a method for supporting management of sidelink feedback to a base station according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An implementation is described that manages sidelink feedback to a base station, e.g., related to a UE acquiring from the base station an SL grant including a COT for a portion of the unlicensed spectrum, which allows the acquiring UE to transmit SL control and data information to a secondary UE. The acquiring UE may also share the COT with the secondary UE, which allows the secondary UE to transmit SL control and data to the acquiring UE or another UE. The acquiring UE performs a CCA, such as Cat 2 LBT or Cat 4 LBT, on one or more SL resources associated with the SL grant. The UE returns SL HARQ feedback to the base station based at least in part on the status of the CCA. In returning the SL HARQ feedback to the base station, the acquiring UE accounts for a variety of different occurrences, such as CCA failed on one or more SL resources, no PSFCH was received from the secondary UE before the SL HARQ feedback is to be transmitted to the base station, etc.

[0013] For example, in the event that CCA fails on all of one or more SL resources, the UE may return SL HARQ feedback that is an ACK in the PUCCH resources, switch to an autonomous resource allocation mode to select further SL resources, return SL HARQ feedback that is a NACK in the corresponding PUCCH resources to obtain further SL transmission grants from the base station, use a separate PUCCH resource to distinguish CCA success or failure from SL data decoding failure, etc.

[0014] As another example, in the event that a PSFCH is not received in the sidelink before a PUCCH resource is to transmit SL HARQ feedback to the base station, the UE may transmit a DTX transmission in the PUCCH resource and transmit a NACK in the corresponding PUCCH resource, but when the UE later receives an ACK from the PSFCH for the previous SL transmission, the UE may choose to ignore the new SL grant (received in response to the NACK), the UE may transmit a NACK in the corresponding PUCCH resource, but when the UE still has not received any SL HARQ feedback from the PSFCH for the previous SL transmission, the UE may retransmit in the received SL grant (received in response to the NACK), use a separate PUCCH resource to help distinguish delayed reception of the PSFCH due to CCA failure from that of SL data decoding failure, etc.

[0015] By using the described techniques, an acquiring UE can provide feedback to the base station based on the status of the CCA that allows the base station to respond appropriately to the feedback and allows the acquiring UE to use SL grants. For example, the need for the base station to send retransmit SL grants can be mitigated because the UE is not constrained to only send NACKs in all circumstances. The UE can proceed with sidelink communication using SL grants, albeit with some delay, and no resources are expended on new SL grants. Furthermore, the base station can distinguish CCA (e.g., LBT) failures with respect to HARQ failures and provide resources accordingly.

[0016] Aspects of the present disclosure are described in the context of a wireless communication system, which are further illustrated and described with reference to device diagrams and flow charts relating to managing sidelink feedback to a base station.

[0017] FIG. 1 illustrates an example of a wireless communication system 100 supporting management of sidelink feedback to a base station according to aspects of the disclosure. The wireless communication system 100 may include one or more base stations 102, one or more UEs 104, and a core network 106. The wireless communication system 100 may support various radio access technologies. In some implementations, the wireless communication system 100 may be a 4G network, such as an LTE network or an LTE-Advanced (LTE-A) network. In some other implementations, the wireless communication system 100 may be a 5G network, such as an NR network. In other implementations, the wireless communication system 100 may be a combination of a 4G network and a 5G network. The wireless communication system 100 may support radio access technologies beyond 5G. Additionally, the wireless communication system 100 may support technologies such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc.

[0018] One or more base stations 102 may be distributed in a geographic region to form a wireless communication system 100. One or more of the base stations 102 described herein may be or include or be referred to as a base transceiver station, access point, Node B, eNode B (eNB), next generation Node B (gNB), radio head (RH), relay node, integrated access and backhaul (IAB) node, or other suitable terminology. The base station 102 and the UE 104 may communicate over a communication link 108, which may be a wireless or wired connection. For example, the base station 102 and the UE 104 may conduct wireless communication over an NR Uu interface.

[0019] A base station 102 may provide a geographic coverage area 110 for which the base station 102 may support services (e.g., voice, video, packet data, messaging, broadcast, etc.) for one or more UEs 104 within the geographic coverage area. For example, the base station 102 and the UEs 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or more radio access technologies. In some implementations, the base station 102 may be mobile, for example, when implemented as a gNB aboard a satellite or other non-terrestrial station (NTS) associated with a non-terrestrial based network (NTN). In some implementations, different geographic coverage areas 110 associated with the same or different radio access technologies may overlap, and different geographic coverage areas 110 may be associated with different base stations 102. Information and signals described herein may be represented using any of a wide variety of technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols and chips that may be referenced throughout this description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0020] One or more UEs 104 may be distributed in a geographic region or coverage area 110 of the wireless communication system 100. The UEs 104 may include or be referred to as a mobile device, a wireless device, a remote device, a handheld device, a customer premises equipment (CPE), a subscriber device, or any other suitable term. In some implementations, the UEs 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally or alternatively, the UEs 104 may be referred to as an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a Machine Type Communication (MTC) device, among other examples. In some implementations, the UEs 104 may be stationary within the wireless communication system 100. In other implementations, the UEs 104 may be mobile within the wireless communication system 100, such as a moving earth station (ESIM).

[0021] One or more UEs 104 may be devices of different shapes or with different capabilities. Several examples of UEs 104 are shown in FIG. 1. The UE 104 may be capable of communicating with various types of devices, such as base stations 102, other UEs 104, or network equipment (e.g., a core network 106, relay devices, gateway devices, integrated access and backhaul (IAB) nodes, location servers implementing a location management function (LMF), or other network equipment). Additionally or alternatively, the UE 104 may support communication with other base stations 102 or UEs 104, which may act as relays in the wireless communication system 100.

[0022] The UE 104 may also support direct wireless communication with other UEs 104 via the communication link 112. For example, the UE 104 may support direct wireless communication with another UE 104 via a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V), vehicle-to-exchange (V2X), or cellular V2X deployments, the communication link 112 may be referred to as a sidelink. For example, the UE 104 may support direct wireless communication with another UE 104 via a PC5 interface.

[0023] The base stations 102 may support communication with the core network 106 or with other base stations 102, or both. For example, the base stations 102 may interface with the core network 106 through one or more backhaul links 114 (e.g., via an S1, N2, or other network interface). The base stations 102 may communicate with each other through the backhaul links 114 (e.g., by an X2, Xn, or other network interface). In some implementations, the base stations 102 may communicate with each other directly (e.g., between the base stations 102). In some other implementations, the base stations 102 may communicate with each other indirectly (e.g., via the core network 106). In some implementations, one or more base stations 102 may include sub-components such as an access network entity, which may be an example of an access node controller (ANC). The ANC may communicate with one or more UEs 104 through one or more other access network transmission entities, which may be referred to as remote radio heads, smart radio heads, gateways, transmit receive points (TRPs), and other network nodes and / or entities.

[0024] The core network 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The core network 106 may be an Evolved Packet Core (EPC) or 5G Core (5GC), which may include a control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) that manages access and mobility, as well as a user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) that routes packets or interconnects to external networks. In some implementations, the control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for one or more UEs 104 served by one or more base stations 102 associated with the core network 106.

[0025] According to some implementations, the UE 104 and one or more of the base stations 102 are operable to implement various aspects of managing sidelink feedback to the base station described herein. For example, the base station 102 can communicate an SL grant 116 to the UE 104 that enables the UE 104 to use SL resources and time to directly communicate with other UEs 104. In one or more implementations, the SL grant 116 includes various information, such as a COT sharing indicator, one or more SL resources, remaining CO duration, etc. The UE 104 receives the SL grant 116 and performs SL management 118 to manage SL communications (e.g., via communication 112) with one or more other UEs 104. The SL management 118 includes various operations such as performing CCA, transmitting control information or data to another UE 104, receiving control information or data from another UE 104, sharing an SL grant 116 (e.g., a portion of the COT granted for the UE 104) with one or more other UEs 104, returning SL feedback 120 to the base station 102, etc.

[0026] The UE 104 communicates with the base station 102 using any of various types of control signaling, such as at least one of radio resource control (RRC), downlink control information (DCI), uplink control information (UCI), medium access control (MAC) control element (CE), HARQ (e.g., SL HARQ), etc. Similarly, the UE 104 communicates with other UEs 104 using any of various types of control signaling, such as at least one of RRC, sidelink control information (SCI), MAC CE, HARQ (e.g., SL HARQ), etc.

[0027] In an aspect of managing sidelink feedback to the base station, a channel access priority class (CAPC) is used. Table 1 includes example CAPCs, where p refers to CAPC and m p refers to the number of backoff stages for a given priority class p, and CW min,pdenotes the minimum contention window for a given priority class p, and CW max,p denotes the maximum contention window for a given priority class p, and T mcot,p denotes the maximum channel occupancy time (MCOT) for a given priority class p (e.g., in milliseconds (ms)), and cw p denotes the contention window for a given priority class p.

[0028] [Table 1]

[0029] 2 illustrates a system 200 that supports management of sidelink feedback to a base station according to an aspect of the disclosure. The system 200 may be implemented using and / or in conjunction with the wireless communication system 100. The system 200 includes an initiating UE 202 (also referred to as an acquiring UE), which is the UE 104 of FIG. 1 that is referred to as the initiating UE because the UE 202 acquires and initiates SL communication with one or more other UEs, also referred to as secondary UEs. The initiating UE 202 acquires a COT (e.g., in an unlicensed spectrum) as part of a sidelink grant 204 (e.g., the SL grant 116 of FIG. 1) from, for example, the base station 102.

[0030] The initiating UE 202 performs CCA, such as LBT (e.g., Cat 2 LBT or Cat 4 LBT), on one or more sidelink resources 206 associated with the sidelink grant 204. CCA refers to checking whether a resource (e.g., a channel or frequency band) is clear or free, e.g., not being used by another device. CCA is performed using any of a variety of public or proprietary techniques, such as determining whether the amount of energy on the resource is below a threshold amount. The CCA for each of the one or more resources can be successful (the resource is clear or free) or unsuccessful (the resource is not clear or free).

[0031] After the initiator UE 202 performs successful CCA on at least one of the one or more sidelink resources 206, it transmits control information or data to one or more of the secondary UEs 208, 210, or 212. The initiator UE 202 also receives control information or data from one or more of the secondary UEs 208, 210, or 212. The initiator UE 202 may share a COT with one or more of the secondary UEs 208, 210, or 212, which may then use the shared portion of the COT to transmit control information or data to (and receive control information or data from) the UE 202 or another secondary UE 208, 210, or 212. Each secondary UE 208, 210, or 212 performs CCA before transmitting control information or data on one or more sidelink resources 206 and does not proceed with transmission until the CCA is successful.

[0032] The initiating UE 202 returns SL feedback 214 (e.g., SL feedback 120 of FIG. 1 ), which may be SL HARQ feedback, to the base station 102. The initiating UE 202 determines the appropriate SL feedback 214 based at least in part on the status of the performed CCA. The status of the CCA refers to whether the CCA was successful or failed. The initiating UE 202 can provide different SL HARQ feedback based at least in part on the CCA status, as discussed in more detail below. This SL HARQ feedback can be based at least in part on the CCA status of one or more secondary UEs 208, 210, or 212. For example, the secondary UEs 208, 210, or 212 may be delayed from transmitting a PSFCH due to a CCA failure (or optionally other reasons) on one or more sidelink resources 206.

[0033] In one or more implementations, the SL grant 116 (e.g., in a new DCI format) may include up to a maximum number of SL resources (e.g., a multi-slot SL resource including no more than three or more than three consecutive SL resources), and the SL grant (e.g., DCI) may indicate at least one of a channel access priority class, an MCOT duration, a remaining channel occupation duration, an LBT or other CCA type, a COT sharing indicator (e.g., an indication that the initiating UE 202 may share one or more of the SL resources associated with the SL grant 116 with one or more secondary UEs), one or more destination identifiers (IDs) for the SL (e.g., IDs of one or more secondary UEs that may share one or more of the SL resources associated with the SL grant 116 with the initiating UE 202), etc. The size of the SL grant may be a new DCI format aligned with the existing DCI format 3_0 by using padding bits, which may be used to schedule SL transmissions in the unlicensed spectrum.

[0034] After successfully receiving the SL grant 116, the initiating UE 202 may perform CCA, such as LBT according to the LBT type indicated in the DCI. Additionally or alternatively, the initiating UE 202 may use Cat 4 LBT for initiating channel occupancy when there is no LBT type field in the DCI, and in case of COT sharing for sidelink transmissions initiated by the base station 102 (e.g., indicated by a COT sharing indicator in the SL grant 116), the initiating UE 202 may use Cat 2 LBT.

[0035] The initiating UE 202 may implement Cat 4 LBT and initiate channel occupancy according to a channel access priority class value provided in the DCI. Additionally or alternatively, the initiating UE 202 may choose a channel access priority class value according to a data priority or latency selected according to a defined Logical Channel Prioritization (LCP) rule, and then initiate channel occupancy.

[0036] In one or more implementations, the initiating UE 202 may perform CCA (e.g., Cat 4 LBT) at the beginning of a first SL resource indicated in the DCI, and if the CCA fails, the initiating UE 202 may perform CCA (e.g., Cat 4 LBT) at the beginning of a second SL resource indicated in the DCI, and so on until CCA is performed on all SL resources (e.g., indicated in the DCI) associated with the SL grant 116. If CCA (e.g., Cat 4 LBT) fails for all SL resources indicated in the DCI, the initiating UE 202 takes one or more actions.

[0037] In one or more implementations, if CCA (e.g., Cat 4 LBT) fails for all SL resources indicated in the DCI, the initiating UE 202 sends an ACK in the SL HARQ feedback in the corresponding PUCCH resource. The initiating UE 202 also switches to an autonomous resource allocation mode to select another SL resource (other than the SL resource indicated in the DCI) for further transmission. In the autonomous resource allocation mode, the initiating UE 202 selects the SL resource on its own based on some sensing or some pre-configuration of the initiating UE 202.

[0038] Additionally or alternatively, if CCA (e.g., Cat 4 LBT) fails for all SL resources indicated in the DCI, the initiating UE 202 sends a NACK in the SL HARQ feedback in the corresponding PUCCH resource to obtain another SL transmission grant from the base station 102.

[0039] Additionally or alternatively, if CCA (e.g., Cat 4 LBT) fails for all SL resources indicated in the DCI and a switch from base station scheduled SL transmission (e.g., mode 1) to autonomous resource selection (e.g., mode 2) is disabled in the corresponding SL resource pool, the initiating UE 202 sends a NACK in the SL HARQ feedback in the corresponding PUCCH resource to obtain another SL transmission grant from the base station 102.

[0040] Additionally or alternatively, if CCA (e.g., Cat 4 LBT) fails for all SL resources indicated in the DCI, the initiating UE 202 uses a separate PUCCH resource to distinguish CCA success / failure feedback from failure to decode SL data feedback, which may be implemented by using a new field in the DCI. The new field in the DCI may provide a separate PUCCH resource for determining the CCA status for the SL resources indicated in the DCI. The new PUCCH resource for reporting the CCA status may be provided regardless of the PUCCH resource for reporting SL HARQ feedback to the base station 102, and the new PUCCH resource may be provided in a resource pool with PSFCH feedback disabled.

[0041] For example, when the initiating UE 202 encounters a CCA failure while attempting to transmit in the indicated SL resource, the initiating UE 202 may report a CCA failure "0" to the base station 102 in the corresponding new feedback resource, which may help the base station 102 distinguish SL data transmission / decoding failure from CCA success / failure. Conventionally, after the base station 102 receives a SL HARQ feedback report, if it is a NACK, the base station 102 grants a retransmission grant, and if it is an ACK, the base station 102 grants a new SL grant based on a previously transmitted buffer status report (BSR). By adopting this new feedback type for CCA (e.g., LBT) failure, the base station 102 may grant a SL grant for the same HARQ process and the same transport block (TB) size as the previous SL grant after receiving a CCA (e.g., LBT) failure indication.

[0042] 3 shows an example 300 of using separate PUCCH resources. In the example 300, the initiating UE 202 receives a sidelink grant 204 from the base station 102. If CCA (e.g., Cat 4 LBT) fails for all SL resources indicated in the DCI, the initiating UE 202 reports a specific value (e.g., “0”) in PUCCH resource A 302 to indicate a CCA failure and a specific value (e.g., “1”) in PUCCH resource B 304 to indicate that there was no decoding failure. When there was a decoding failure of the SL data feedback, the initiating UE 202 reports a specific value (e.g., “0”) in PUCCH resource B 304 to indicate a decoding failure and a specific value (e.g., “1”) in PUCCH resource A 302 to indicate that there was no CCA failure.

[0043] Returning to Figure 2, in one or more implementations, when the initiating UE 202 receives a COT sharing indicator from the base station 102 for the base station 102-initiated channel occupancy, the SL resources indicated in the DCI received with the COT sharing indicator are within the remaining channel occupancy duration. Thus, the initiating UE 202 may perform Cat 2 LBT prior to transmitting in those SL resources.

[0044] Additionally or alternatively, when the initiating UE 202 receives a COT sharing indicator from the base station 102 for a base station 102 initiated channel occupancy, and the indicated SL resource in the DCI received with the COT sharing indicator is outside the channel occupancy duration, the initiating UE 202 switches to autonomous resource selection (e.g., mode 2) to select an SL resource within the remaining channel occupancy duration indicated in the DCI. The initiating UE 202 performs Cat 4 LBT and initiates a new COT before SL transmission in the SL resource selected by autonomous resource selection.

[0045] Additionally or alternatively, when the initiating UE 202 receives a COT sharing indicator from the base station 102 for channel occupancy initiated by the base station 102 and there are no SL resources signaled in the received COT sharing indicator, the initiating UE 202 switches to autonomous resource selection (e.g., mode 2) to select resources within the remaining channel occupancy duration.

[0046] Additionally or alternatively, when the initiating UE 202 receives a COT sharing indicator from the base station 102 for a channel occupancy initiated by the base station 102, and the indicated SL resource in the DCI received with the COT sharing indicator is outside the channel occupancy duration, the initiating UE 202 ignores the SL grant in the DCI and sends an ACK in the SL HARQ feedback in the corresponding PUCCH resource. The initiating UE 202 switches to autonomous resource selection (e.g., mode 2) to select a resource within the remaining channel occupancy duration.

[0047] Additionally or alternatively, when the initiating UE 202 receives a COT sharing indicator from the base station 102 for the base station 102 initiated channel occupancy, and the initiating UE 202 is configured with configured grant (CG) resources, upon the initiating UE 202 receiving the COT sharing indicator, the initiating UE 202 may implicitly activate start making transmission in the CG resources. The CG resources may be pre-configured (e.g., stored locally) at the initiating UE 202 or may be received by the initiating UE 202 (e.g., from the base station 102) prior to receiving the SL grant.

[0048] In one or more implementations, the PSFCH is not received in the sidelink in time before the PUCCH resource is to transmit the SL HARQ feedback to the base station 102 (e.g., is not received before the PUCCH resource is to transmit the SL HARQ feedback or before the PUCCH preparation time for reporting the SL HARQ feedback to the base station 102). In such an event, the initiating UE 202 may perform a DTX transmission (e.g., indicating that the initiating UE 202 is going into DTX mode or reducing transmission) in the corresponding PUCCH resource (e.g., include a DTX indication in the SL HARQ feedback).

[0049] Additionally or alternatively, if the PSFCH is not received in the sidelink in time before the PUCCH resource is to transmit SL HARQ feedback to the base station 102, the initiating UE 202 transmits a NACK in the SL HARQ feedback for the corresponding PUCCH resource. When the initiating UE 202 later receives an ACK from the PSFCH for the previous SL transmission, the initiating UE 202 may choose to ignore the corresponding SL grant (received in response to the NACK).

[0050] Additionally or alternatively, if the PSFCH is not received in the sidelink in time before the PUCCH resource is to transmit SL HARQ feedback to the base station 102, the initiating UE 202 may transmit a NACK in the SL HARQ feedback for the corresponding PUCCH resource. When the initiating UE 202 later receives an ACK from the PSFCH for the previous SL transmission, the initiating UE 202 may choose to perform a new transmission for the corresponding SL grant.

[0051] Additionally or alternatively, if the PSFCH is not received in the sidelink in time before the PUCCH resource is to transmit SL HARQ feedback to the base station 102, the initiating UE 202 transmits a NACK in the SL HARQ feedback of the corresponding PUCCH resource. When the initiating UE 202 still has not received any SL HARQ feedback from the PSFCH for the previous SL transmission, the initiating UE 202 may retransmit in the received SL grant (received in response to the NACK).

[0052] Additionally or alternatively, if the PSFCH is not received in the sidelink in time before the PUCCH resource is to transmit the SL HARQ feedback to the base station 102, the initiating UE 202 uses a separate PUCCH resource to help distinguish a delay in receiving the PSFCH due to an LBT failure from one due to an SL data decoding failure, which can be implemented by using a new field in the DCI. A new indicator indicating a delay in receiving the PSFCH due to an LBT failure may be transmitted to the base station 102 in the PUCCH resource. The base station 102 may not schedule a retransmission grant or may request or trigger a one-shot SL HARQ feedback report from the initiating UE 202 until the base station 102 receives the corresponding SL HARQ feedback.

[0053] In one or more implementations, a non-numeric SL HARQ feedback indicator is transmitted (e.g., in a new DCI format) by using one of the configured codepoints in the PSFCH-SL inter-HARQ feedback timing indicator. In such implementations, a corresponding PUCCH resource may not be given in the DCI, and thus the SL HARQ feedback report can be postponed until a separate trigger is received.

[0054] The initiating UE 202 may enable non-numeric SL HARQ feedback in the SCI for a corresponding SL grant (eg, an SL grant received with a non-numeric SL HARQ feedback indicator).

[0055] The base station 102 can send such a trigger to request SL HARQ feedback for SL HARQ processes previously indicated with non-numeric SL HARQ feedback, for example, by sending a next DCI scheduling a PSSCH transmission with a numeric PSFCH-SL inter-HARQ feedback timing indicator implying a request for transmission of SL HARQ feedback for SL HARQ processes (e.g., a subset of the SL HARQ processes) previously signaled with a non-numeric SL HARQ feedback indicator. The SL HARQ feedback report can be multiplexed in PUSCH or PUCCH resources, which can be provided by the base station 102 for transmitting the SL HARQ feedback report.

[0056] Additionally or alternatively, when the initiating UE 202 autonomously decides to transmit a non-numeric SL HARQ feedback request transmission regardless of the PSFCH-SL inter-HARQ feedback timing indicator, the initiating UE 202 may transmit a DTX transmission in the corresponding PUCCH resource. Additionally or alternatively, the initiating UE 202 may transmit other data or control information as described above. For example, the initiating UE 202 may transmit an ACK in the SL HARQ feedback in the corresponding PUCCH resource. As another example, the initiating UE 202 transmits a NACK in the SL HARQ feedback in the corresponding PUCCH resource to obtain another SL transmission grant from the base station 102. As another example, the initiating UE 202 uses a separate PUCCH resource to distinguish CCA success / failure feedback from decoding failure of SL data feedback, which can be implemented by using a new field in the DCI. The new field in the DCI may provide a separate PUCCH resource for determining the CCA status for the SL resource indicated in the DCI. The new PUCCH resource for reporting the CCA status may be provided regardless of the PUCCH resource for reporting SL HARQ feedback to the base station 102, and the new PUCCH resource may be provided in a resource pool where PSFCH feedback is disabled.

[0057] In one or more implementations, the base station 102 may initiate a new COT after successfully performing CCA (e.g., Cat 4 LBT) and may transmit in a first DCI to the initiating UE 202 or destination ID to indicate intent for COT sharing using a unicast DCI or group common DCI format for scheduling sidelink. The actual trigger including the start slot and remaining CO duration for COT sharing may be indicated by a follow-up using a second DCI. In this event, the remaining CO duration may be calculated from the slot where the initiating UE 202 detects the second SCI. The remaining CO duration may be calculated, for example, from the receiving time slot of the second DCI.

[0058] Additionally or alternatively, the base station 102 may initiate a new COT after successfully performing CCA (e.g., Cat 4 LBT) and may transmit a COT sharing indicator in a DCI that includes a time gap value (e.g., 3 bits) determined by higher layer parameters (e.g., sl-DCI-ToSL-Trans) that may indicate the start of a CO duration for SL data transmission.

[0059] In one or more implementations, the initiating UE 202 may require preparation or processing time to perform autonomous resource selection (e.g., mode 2) to select SL resources after receiving a COT sharing indicator from the base station 102 (e.g., when no SL resources are signaled in the received COT sharing indicator). The preparation or processing time can be achieved with the above options of using a time gap field in the DCI and / or using two DCIs to indicate COT sharing.

[0060] FIG. 4 illustrates an example block diagram 400 of a device 402 supporting management of sidelink feedback to a base station according to aspects of the disclosure. The device 402 may be an example of a UE 104 as described herein. The device 402 may support wireless communication and / or network signaling with one or more base stations 102, other UEs 104, network entities and devices, or any combination thereof. The device 402 may include components for bidirectional communication, including components for transmitting and receiving communications, such as a communications manager 404, a processor 406, a memory 408, a receiver 410, a transmitter 412, and an I / O controller 414. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0061] The communications manager 404, the receiver 410, the transmitter 412, or various combinations or components thereof may be examples of means for implementing various aspects of the disclosure described herein. For example, the communications manager 404, the receiver 410, the transmitter 412, or various combinations or components thereof may support a method for implementing one or more of the functions described herein.

[0062] In some implementations, the communications manager 404, the receiver 410, the transmitter 412, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing functions described in this disclosure. In some implementations, the processor 406, and a memory 408 coupled with the processor 406, may be configured to perform one or more of the functions described herein (e.g., by the processor 406 executing instructions stored in the memory 408).

[0063] Additionally or alternatively, in some implementations, the communications manager 404, the receiver 410, the transmitter 412, or various combinations or components thereof may be implemented in code executed by the processor 406 (e.g., as communications management software or firmware). When implemented in code executed by the processor 406, the functions of the communications manager 404, the receiver 410, the transmitter 412, or various combinations or components thereof may be performed by a general purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a means for performing the functions described in this disclosure).

[0064] In some implementations, the communications manager 404 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise cooperating with the receiver 410, the transmitter 412, or both. For example, the communications manager 404 may be integrated to receive information from the receiver 410, send information to the transmitter 412, or in combination with the receiver 410, the transmitter 412, or both to receive information, transmit information, or perform various other operations described herein. Although the communications manager 404 is shown as a separate component, in some implementations, one or more functions described with respect to the communications manager 404 may be supported or performed by the processor 406, the memory 408, or any combination thereof. For example, the memory 408 may store code, which may include instructions executable by the processor 406 to cause the device 402 to perform various aspects of the disclosure described herein, or the processor 406 and the memory 408 may be otherwise configured to perform or support such operations.

[0065] For example, the communications manager 404 may support wireless communications and / or network signaling in a device (e.g., device 402, i.e., a UE) in accordance with examples disclosed herein. The communications manager 404 and / or other device components may be configured as or otherwise support an apparatus, such as a UE, including a transceiver and a processor coupled to the transceiver, where the processor and transceiver are configured to cause the apparatus to receive, from a base station, first control signaling indicating a first SL grant having one or more associated SL resources, perform CCA for the one or more associated SL resources, and transmit second control signaling to the base station based at least in part on a status of the CCA.

[0066] The apparatus (e.g., a UE) may further include a situation in which the processor and transceiver are further configured to cause the apparatus to perform autonomous resource selection to obtain resources for the first SL grant in response to determining that one or more SL resources are not included in the first SL grant or that one or more SL resources are outside the remaining CO; a situation in which the second control signaling includes SL HARQ feedback and the processor and transceiver are further configured to cause the apparatus to transmit DTX in the SL HARQ feedback in response to a PSFCH not being received from the second apparatus over the one or more SL resources before the PUCCH resource is to transmit the SL HARQ feedback to the base station; a situation in which the second control signaling includes SL HARQ feedback and the processor and transceiver are further configured to cause the apparatus to transmit DTX in the SL HARQ feedback in response to a PSFCH not being received from the second apparatus over the one or more SL resources before the PUCCH resource is to transmit the SL HARQ feedback to the base station; a situation in which the second control signaling includes a first SL HARQ feedback in the first PUCCH resource indicating a first status of CCA when CCA fails for one or more SL resources, or a second SL HARQ feedback in the second PUCCH resource indicating a second status of CCA when a decoding failure of SL data occurs; a situation in which the first SL grant identifies one or more of an associated SL resource, a COT sharing indicator, or a remaining CO duration; a situation in which the second control signaling includes a SL HARQ feedback; a situation in which the second control signaling includes a SL HARQ feedback;a situation in which the second control signaling includes a SL HARQ feedback and the processor and transceiver are further configured to cause the apparatus to include an ACK in the SL HARQ feedback in response to the CCA failing for the one or more SL resources and to perform autonomous resource selection to obtain resources for the first SL grant; a situation in which the second control signaling includes a SL HARQ feedback and the processor and transceiver are further configured to cause the apparatus to include a NACK in the SL HARQ feedback in response to the CCA failing for the one or more SL resources and to receive a second SL grant from the base station in response to the SL HARQ feedback; a situation in which the processor and transceiver cause the apparatus to select a Cat 2 SL grant as the CCA in response to the first SL grant identifying a COT sharing indicator and one or more associated SL resources. a situation in which the processor and transceiver are further configured to cause the device to perform an autonomous resource selection to obtain resources for the first SL grant within the remaining CO duration in response to the first SL grant not identifying one or more associated SL resources; a situation in which the second control signaling includes SL HARQ feedback and the processor and transceiver are further configured to cause the device to transmit a NACK in the SL HARQ feedback in response to a PSFCH not being received from the second device over the one or more SL resources before the PUCCH resource is to transmit the SL HARQ feedback to the base station; receive third control signaling from the base station indicating the second SL grant; and transmit a new transmission to the second device over the one or more SL resources associated with the second SL grant in response to a PSFCH not being received from the second device over the one or more SL resources before the PUCCH resource is to transmit the SL HARQ feedback to the base station;the processor and transceiver are further configured to cause the device to transmit, in the second PUCCH resource, SL HARQ feedback indicating a delay in receiving the PSFCH in response to the PSFCH not being received from the second device over the one or more SL resources before transmitting the HARQ feedback to the base station; the processor and transceiver are further configured to cause the device to receive from the base station a non-numeric SL HARQ feedback indicator, receive from the base station a trigger to request SL HARQ feedback after receiving the non-numeric SL HARQ feedback indicator, and transmit second control signaling to the base station in response to the trigger; and the processor and transceiver are further configured to cause the device to receive from the base station an indication of a start of a CO duration for transmission on the one or more associated SL resources as part of the first control signaling, and perform autonomous resource selection to obtain resources for the first SL grant during the time gap indicated by the start of the CO duration. The communications manager 404 and / or other device components may be configured with or otherwise support a means for wireless communications and / or network signaling in the UE, including receiving first control signaling from a base station indicating a first SL grant having one or more associated SL resources, performing CCA for the one or more associated SL resources, and sending second control signaling to the base station based at least in part on the status of the CCA.

[0067] Further, the wireless communication and / or network signaling at the UE includes performing autonomous resource selection to obtain resources for the first SL grant in response to determining that the one or more SL resources are not included in the first SL grant or that the one or more SL resources are outside the remaining CO; the second control signaling includes SL HARQ feedback, and in response to a PSFCH not being received from the second device over the one or more SL resources before the PUCCH resource is to transmit the SL HARQ feedback to the base station, transmitting a DTX in the SL HARQ feedback; the second control signaling includes SL HARQ feedback, and in response to a PSFCH not being received from the second device over the one or more SL resources before the PUCCH resource is to transmit the SL HARQ feedback to the base station, transmitting a NACK in the SL HARQ feedback; receiving third control signaling from the base station indicating the second SL grant; and a situation in which the second control signaling includes a first SL HARQ feedback in the first PUCCH resource indicating a first status of the CCA when the CCA fails for one or more SL resources, or a second SL HARQ feedback in the second PUCCH resource indicating a second status of the CCA when a decoding failure of the SL data occurs; a situation in which the first SL grant identifies one or more of an associated SL resource, a COT sharing indicator, or a remaining CO duration; and the second control signaling includes the SL HARQ feedback; and a situation in which the second control signaling includes the SL HARQ feedback, and in response to the CCA failing for the one or more SL resources, including an ACK in the SL HARQ feedback; and performing autonomous resource selection to obtain resources for the first SL grant; and the second control signaling includes a second SL HARQ feedback in the first PUCCH resource indicating a first status of the CCA when the CCA fails for one or more SL resources.receiving a second SL grant from the base station in response to the SL HARQ feedback, the second SL grant including a NACK in the SL HARQ feedback in response to the CCA failing for the one or more SL resources; performing Cat 2 LBT as a CCA in response to the first SL grant identifying a COT sharing indicator and one or more associated SL resources; performing autonomous resource selection to obtain resources for the first SL grant within a remaining CO duration in response to the first SL grant not identifying the one or more associated SL resources; the second control signaling including the SL HARQ feedback, the SL HARQ feedback in response to the PUCCH resource not being received from the second device over the one or more SL resources before the PUCCH resource is to be transmitted to the base station; transmitting a NACK in the HARQ feedback; receiving third control signaling from the base station indicating a second SL grant; in response to the PSFCH not being received from the second device via the one or more SL resources, transmitting a new transmission to the second device via the one or more SL resources associated with the second SL grant, the second control signaling including the SL HARQ feedback, transmitting SL HARQ feedback in the second PUCCH resource indicating a delay in receiving the PSFCH in response to the PSFCH not being received from the second device via the one or more SL resources before the first PUCCH resource is to transmit the SL HARQ feedback to the base station; receiving a non-numeric SL HARQ feedback indicator from the base station; and receiving a SL HARQ feedback indicator from the base station after receiving the non-numeric SL HARQ feedback indicator from the base station.The method includes any one or combination of receiving a trigger to request HARQ feedback, transmitting second control signaling to the base station in response to the trigger, receiving an indication of a start of a CO duration for transmission on one or more associated SL resources from the base station as part of the first control signaling, and performing autonomous resource selection to obtain resources for the first SL grant during the time gap indicated by the start of the CO duration.

[0068] The processor 406 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some implementations, the processor 406 may be configured to operate a memory array using a memory controller. In some implementations, the memory controller may be integrated into the processor 406. The processor 406 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 408) to cause the device 402 to perform various functions of the disclosure.

[0069] The memory 408 may include random access memory (RAM) and read only memory (ROM). The memory 408 may store computer-readable computer-executable code including instructions that, when executed by the processor 406, cause the device 402 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as a system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 406, but may (e.g., when compiled and executed) cause a computer to perform functions described herein. In some implementations, the memory 408 may include a basic input / output system (BIOS), which may control basic hardware or software operations, such as interactions with peripheral components or devices, among others.

[0070] The I / O controller 414 may manage input and output signals for the device 402. The I / O controller 414 may also manage peripheral devices that are not integrated into the device 402. In some implementations, the I / O controller 414 may represent a physical connection or port to an external peripheral device. In some implementations, the I / O controller 414 may use an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I / O controller 414 may be implemented as part of a processor, such as the processor 406. In some implementations, a user may interact with the device 402 through the I / O controller 414 or through hardware components controlled by the I / O controller 414.

[0071] In some implementations, the device 402 may include a single antenna 416. However, in other implementations, the device 402 may have two or more antennas 416, which may be capable of simultaneously transmitting or receiving multiple wireless transmissions. The receiver 410 and the transmitter 412 may communicate bidirectionally over one or more antennas 416, wired or wireless links as described herein. For example, the receiver 410 and the transmitter 412 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver may include a modem for demodulating packets received from the one or more antennas 416 and for modulating the packets and providing the modulated packets to the one or more antennas 416 for transmission.

[0072] FIG. 5 illustrates an example block diagram 500 of a device 502 supporting management of sidelink feedback to a base station according to aspects of the disclosure. The device 502 may be an example of a base station 102, such as a gNB, as described herein. The device 502 may support wireless communication and / or network signaling with one or more base stations 102, other UEs 104, core network devices and functions (e.g., core network 106), or any combination thereof. The device 502 may include components for bidirectional communication, including components for transmitting and receiving communications, such as a communications manager 504, a processor 506, a memory 508, a receiver 510, a transmitter 512, and an I / O controller 514. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0073] The communications manager 504, the receiver 510, the transmitter 512, or various combinations or components thereof may be examples of means for implementing various aspects of the disclosure described herein. For example, the communications manager 504, the receiver 510, the transmitter 512, or various combinations or components thereof may support a method for implementing one or more of the functions described herein.

[0074] In some implementations, the communications manager 504, the receiver 510, the transmitter 512, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing functions described in this disclosure. In some implementations, the processor 506 and a memory 508 coupled with the processor 506 may be configured to perform one or more of the functions described herein (e.g., by the processor 506 executing instructions stored in the memory 508).

[0075] Additionally or alternatively, in some implementations, the communications manager 504, the receiver 510, the transmitter 512, or various combinations or components thereof may be implemented in code executed by the processor 506 (e.g., as communications management software or firmware). When implemented in code executed by the processor 506, the functions of the communications manager 504, the receiver 510, the transmitter 512, or various combinations or components thereof may be performed by a general purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a means for performing the functions described in this disclosure).

[0076] In some implementations, the communications manager 504 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise cooperating with the receiver 510, the transmitter 512, or both. For example, the communications manager 504 may be integrated to receive information from the receiver 510, send information to the transmitter 512, or in combination with the receiver 510, the transmitter 512, or both to receive information, transmit information, or perform various other operations described herein. Although the communications manager 504 is shown as a separate component, in some implementations, one or more functions described with respect to the communications manager 504 may be supported or performed by the processor 506, the memory 508, or any combination thereof. For example, the memory 508 may store code, which may include instructions executable by the processor 506 to cause the device 502 to perform various aspects of the disclosure described herein, or the processor 506 and the memory 508 may be otherwise configured to perform or support such operations.

[0077] For example, the communications manager 504 may support wireless communications and / or network signaling in a device (e.g., device 502, a base station) in accordance with examples disclosed herein. The communications manager 504 and / or other device components may be configured as or otherwise support an apparatus, such as a base station, including a transceiver and a processor coupled to the transceiver, where the processor and transceiver are configured to cause the apparatus to send first control signaling to a UE indicating a first SL grant having one or more associated SL resources, and to receive second control signaling from the UE based at least in part on a status of a CCA implemented by the UE for the one or more associated SL resources.

[0078] Further, the apparatus (e.g., a base station) includes any one or combination of the following situations: the second control signaling includes a first SL HARQ feedback in a first PUCCH resource indicating a first status of the CCA when CCA fails for one or more SL resources, or a second SL HARQ feedback in a second PUCCH resource indicating a second status of the CCA when a decoding failure of SL data occurs, and the processor and transceiver are further configured to cause the apparatus to send a non-numeric SL HARQ feedback indicator to the UE, send a trigger to the UE after sending the non-numeric SL HARQ feedback indicator to request SL HARQ feedback, and receive the second control signaling from the UE in response to the trigger.

[0079] The communications manager 504 and / or other device components may be configured with or otherwise support a means for wireless communications and / or network signaling at the base station, including sending first control signaling to the UE indicating a first SL grant having one or more associated SL resources, and receiving second control signaling from the UE based at least in part on the status of a CCA performed by the UE for the one or more associated SL resources.

[0080] Further, the wireless communication in the base station includes a situation where the second control signaling includes a first SL HARQ feedback in a first PUCCH resource indicating a first status of the CCA when CCA fails for one or more SL resources, or a second SL HARQ feedback in a second PUCCH resource indicating a second status of the CCA when a decoding failure of SL data occurs, and any one or combination of: transmitting a non-numeric SL HARQ feedback indicator to the UE; transmitting a trigger to the UE for requesting SL HARQ feedback after transmitting the non-numeric SL HARQ feedback indicator; and receiving the second control signaling from the UE in response to the trigger.

[0081] The processor 506 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some implementations, the processor 506 may be configured to operate a memory array using a memory controller. In some implementations, the memory controller may be integrated into the processor 506. The processor 506 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 508) to cause the device 502 to perform various functions of the present disclosure.

[0082] The memory 508 may include random access memory (RAM) and read only memory (ROM). The memory 508 may store computer-readable computer-executable code including instructions that, when executed by the processor 506, cause the device 502 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as a system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 506, but may (e.g., when compiled and executed) cause a computer to perform functions described herein. In some implementations, the memory 508 may include a basic input / output system (BIOS), which may control basic hardware or software operations, such as interaction with peripheral components or devices, among others.

[0083] The I / O controller 514 may manage input and output signals for the device 502. The I / O controller 514 may also manage peripheral devices that are not integrated into the device 502. In some implementations, the I / O controller 514 may represent a physical connection or port to an external peripheral device. In some implementations, the I / O controller 514 may use an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I / O controller 514 may be implemented as part of a processor, such as the processor 506. In some implementations, a user may interact with the device 502 through the I / O controller 514 or through hardware components controlled by the I / O controller 514.

[0084] In some implementations, the device 502 may include a single antenna 516. However, in other implementations, the device 502 may have two or more antennas 516, which may be capable of simultaneously transmitting or receiving multiple wireless transmissions. The receiver 510 and the transmitter 512 may communicate bidirectionally over one or more antennas 516, wired or wireless links as described herein. For example, the receiver 510 and the transmitter 512 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver may include a modem for demodulating packets received from the one or more antennas 516 and for modulating the packets and providing the modulated packets to the one or more antennas 516 for transmission.

[0085] 6 illustrates a flowchart of a method 600 for supporting management of sidelink feedback to a base station according to an aspect of the disclosure. The operations of the method 600 may be implemented and performed by a device, such as the UE 104 or UE 202, or components thereof, described with reference to FIGS. 1-5. In some implementations, the device may execute a set of instructions to control functional elements of the device to perform the described functions. Additionally or alternatively, the device may perform aspects of the described functions using dedicated hardware.

[0086] At 602, the method may include receiving, from a base station, first control signaling indicating a first SL grant having one or more associated SL resources. The operations of 602 may be performed according to examples described herein. In some implementations, aspects of the operations of 602 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0087] At 604, the method may include performing CCA for the one or more associated SL resources. The operations of 604 may be performed according to examples described herein. In some implementations, aspects of the operations of 604 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0088] At 606, the method may include transmitting second control signaling to the base station based at least in part on the status of the CCA. The operations of 606 may be performed according to examples described herein. In some implementations, aspects of the operations of 606 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0089] 7 illustrates a flowchart of a method 700 for supporting management of sidelink feedback to a base station according to an aspect of the disclosure. The operations of the method 700 may be implemented and performed by a device, such as the UE 104 or UE 202, or components thereof, described with reference to FIGS. 1-5. In some implementations, the device may execute a set of instructions to control functional elements of the device to perform the described functions. Additionally or alternatively, the device may perform aspects of the described functions using dedicated hardware.

[0090] At 702, the method may include transmitting a NACK in the SL HARQ feedback. The operations of 702 may be performed according to examples described herein. In some implementations, aspects of the operations of 702 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0091] At 704, the method may include receiving, from the base station, third control signaling indicating the second SL grant. The operations of 704 may be performed according to examples described herein. In some implementations, aspects of the operations of 704 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0092] At 706, the method may include ignoring the second SL grant in response to the PSFCH being received from the second device over the one or more SL resources after the SL HARQ feedback is transmitted to the base station. The operations of 706 may be performed according to examples described herein. In some implementations, aspects of the operations of 706 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0093] 8 illustrates a flowchart of a method 800 for supporting management of sidelink feedback to a base station according to an aspect of the disclosure. The operations of the method 800 may be implemented and performed by a device, such as the UE 104 or UE 202, or components thereof, described with reference to FIGS. 1-5. In some implementations, the device may execute a set of instructions to control functional elements of the device to perform the described functions. Additionally or alternatively, the device may perform aspects of the described functions using dedicated hardware.

[0094] At 802, the method may include receiving a non-numeric SL HARQ feedback indicator from a base station. The operations of 802 may be performed according to examples described herein. In some implementations, aspects of the operations of 802 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0095] At 804, the method may include receiving a trigger to request SL HARQ feedback from a base station after receiving the non-numeric SL HARQ feedback indicator. The operations of 804 may be performed according to examples described herein. In some implementations, aspects of the operations of 804 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0096] At 806, the method may include transmitting second control signaling to the base station in response to the trigger. The operations of 806 may be performed according to examples described herein. In some implementations, aspects of the operations of 806 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0097] 9 illustrates a flowchart of a method 900 for supporting management of sidelink feedback to a base station according to an aspect of the disclosure. The operations of the method 900 may be implemented and performed by a device, such as the UE 104 or UE 202, or components thereof, described with reference to FIGS. 1-5. In some implementations, the device may execute a set of instructions to control functional elements of the device to perform the described functions. Additionally or alternatively, the device may perform aspects of the described functions using dedicated hardware.

[0098] At 902, the method may include receiving an indication of a start of a CO duration for transmission on one or more associated SL resources as part of a first control signaling from a base station. The operations of 902 may be performed according to examples described herein. In some implementations, aspects of the operations of 902 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0099] At 904, the method may include performing autonomous resource selection to acquire resources for the first SL grant during the time gap indicated by the start of the CO duration. The operations of 904 may be performed according to examples described herein. In some implementations, aspects of the operations of 904 may be performed by a device described with reference to FIG. 1 or FIG. 2.

[0100] 10 illustrates a flowchart of a method 1000 for supporting management of sidelink feedback to a base station according to an aspect of the disclosure. The operations of the method 1000 may be implemented and performed by a device or components thereof, such as the base station 102, described with reference to FIGS. 1-5. In some implementations, the device may execute a set of instructions to control functional elements of the device to perform the described functions. Additionally or alternatively, the device may perform aspects of the described functions using dedicated hardware.

[0101] At 1002, the method may include transmitting, to the UE, first control signaling indicating a first SL grant having one or more associated SL resources. The operations of 1002 may be performed according to examples described herein. In some implementations, aspects of the operations of 1002 may be performed by a device described with reference to FIG.

[0102] At 1004, the method may include receiving, from the UE, a second control signaling based at least in part on a status of the CCA performed by the UE for the one or more associated SL resources. The operations of 1104 may be performed according to examples described herein. In some implementations, aspects of the operations of 1004 may be performed by a device described with reference to FIG.

[0103] 11 illustrates a flowchart of a method 1100 for supporting management of sidelink feedback to a base station according to an aspect of the disclosure. The operations of the method 1100 may be implemented and performed by a device or components thereof, such as the base station 102, described with reference to FIGS. 1-5. In some implementations, the device may execute a set of instructions to control functional elements of the device to perform the described functions. Additionally or alternatively, the device may perform aspects of the described functions using dedicated hardware.

[0104] At 1102, the method may include transmitting a non-numeric SL HARQ feedback indicator to the UE. The operations of 1102 may be performed according to examples described herein. In some implementations, aspects of the operations of 1102 may be performed by a device described with reference to FIG.

[0105] At 1104, the method may include transmitting a trigger to the UE to request SL HARQ feedback after transmitting the non-numeric SL HARQ feedback indicator. The operations of 1104 may be performed according to examples described herein. In some implementations, aspects of the operations of 1104 may be performed by a device described with reference to FIG.

[0106] At 1106, the method may include receiving, from the UE in response to the trigger, second control signaling. In some implementations, aspects of the operations of 1106 may be performed by a device described with reference to FIG.

[0107] It should be noted that the methods described herein represent possible implementations, that operations and steps may be rearranged or possibly altered, and that other implementations are possible. Furthermore, aspects from two or more of the methods may be combined. The order in which the methods are described is not intended to be limiting, and any number or combination of the method operations described may be performed in any order to implement the method, or alternative methods.

[0108] The various example blocks and components described with respect to the disclosure herein may be implemented or performed using a general purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0109] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or a combination thereof. When implemented in software executed by a processor, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features implementing the functions may also be physically located in different locations, including being distributed such that parts of the functions are implemented in different physical locations.

[0110] Computer-readable media includes both non-transitory computer storage media and communication media, including any medium that facilitates transfer of a computer program from one place to another. Non-transitory storage media may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example and not limitation, non-transitory computer-readable media may include RAM, ROM, Electrically Erasable Programmable ROM (EEPROM), Flash memory, Compact Disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory 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.

[0111] Any connection may be properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of computer-readable media. As used herein, disk and disc include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blue-ray discs, where a disk typically reproduces data magnetically and a disc reproduces data optically with a laser. Combinations of the above are also included within the scope of computer-readable media.

[0112] As used herein, including within the claims, "or" used in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such as, for example, a list of at least one of A, B, or C means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Similarly, a list of one or more of A, B, or C means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Also, the phrase "based on" as used herein should not be construed as a reference to a closed set of conditions. For example, an exemplary step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" is intended to be construed in the same manner as the phrase "based at least in part on". Additionally, as used herein, including in the claims, a "set" may include one or more elements.

[0113] The description set forth herein with respect to the accompanying drawings describes exemplary configurations and does not represent every example that may be implemented or that falls within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration" and does not mean "preferred" or "advantageous over other examples." The detailed description includes specific details for the purposes of providing an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0114] The description herein is provided to enable any person skilled in the art to make or use the disclosure. Various modifications of the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. [Explanation of symbols]

[0115] 100 Wireless communication system 102 Base station 104UE 106 Core Network 108 Communication Links 110 Geographic Coverage Areas 112 Communication Links 114 Backhaul Link 116 SL Grant 118 SL Management 120 SL Feedback 200 Systems 202 Start UE, UE 204 Sidelink Grant 206 Sidelink Resources 208 2nd UE 210 Secondary UE 212 Secondary UE 214 SL Feedback 402 Devices 404 Communications Manager 406 Processor 408 Memory 410 Receiver 412 Transmitter 414 I / O Controller 416 Antenna 502 Devices 504 Communications Manager 506 Processor 508 Memory 510 Receiver 512 Transmitter 514 I / O Controller 516 Antenna

Claims

Claim 1: A first user equipment (UE) for wireless communication, comprising: At least one memory; and at least one processor coupled to the at least one memory, the processor configured to: receiving, from a base station, first control signaling indicating a first sidelink (SL) grant having one or more associated SL resources; performing a clear channel assessment (CCA) for the one or more associated SL resources; including a negative acknowledgement (NACK) in hybrid automatic repeat request (HARQ) feedback in response to the CCA failing for the one or more associated SL resources; and transmitting the HARQ feedback to the base station. First UE.

2. The first UE of claim 1, wherein the at least one processor is further configured to cause the first UE to perform autonomous resource selection to obtain resources for the first SL grant in response to determining that the one or more SL resources are not included in the first SL grant or that the one or more SL resources are outside of remaining channel occupancy (CO).

3. The first UE of claim 1, wherein the at least one processor is further configured to cause the first UE to transmit discontinuous transmission (DTX) in the HARQ feedback in response to a physical sidelink feedback channel (PSFCH) not being received from a second UE via the one or more SL resources before a physical uplink control channel (PUCCH) resource is to transmit the HARQ feedback to the base station.

4. The at least one processor, in response to a physical sidelink feedback channel (PSFCH) not being received from a second UE via the one or more SL resources before a physical uplink control channel (PUCCH) resource is to transmit the SL HARQ feedback to the base station, sends to the first UE: transmitting the NACK in the HARQ feedback; receiving second control signaling from the base station indicating a second SL grant; 2. The first UE of claim 1, further configured to: ignore the second SL grant in response to the PSFCH being received from the second UE via the one or more SL resources after the HARQ feedback is transmitted to the base station.

5. The first UE of claim 1, wherein the HARQ feedback is included in a first physical uplink control channel (PUCCH) resource indicating a first status of the CCA when the CCA fails for the one or more SL resources, or in a second PUCCH resource indicating a second status of the CCA when a decoding failure of SL data occurs.

6. The first UE of claim 1, wherein the first SL grant identifies one or more of the associated SL resource, a channel occupation time (COT) sharing indicator, or a remaining channel occupation (CO) duration.

7. The at least one processor, in response to the CCA failing for the one or more SL resources, to the UE: The first UE of claim 1 , further configured to: receive a second SL grant from the base station in response to the HARQ feedback.

8. The first UE of claim 1, wherein the at least one processor is further configured to cause the first UE to perform Cat2 listen-before-talk (LBT) as the CCA in response to the first SL grant identifying a channel occupation time (COT) sharing indicator and the one or more associated SL resources.

9. The first UE of claim 1, wherein the at least one processor is further configured to, in response to the first SL grant not identifying the one or more associated SL resources, cause the first UE to perform autonomous resource selection to obtain resources for the first SL grant within a remaining channel occupancy (CO) duration.

10. The at least one processor, in response to a physical sidelink feedback channel (PSFCH) not being received from a second UE via the one or more SL resources before a physical uplink control channel (PUCCH) resource is to transmit the HARQ feedback to the base station, sends to the first UE: transmitting the NACK in the HARQ feedback; receiving second control signaling from the base station indicating a second SL grant; 10. The first UE of claim 1, further configured to: in response to the PSFCH not being received from the second UE via the one or more SL resources, transmit a new transmission to the second UE via one or more SL resources associated with the second SL grant.

11. The first UE of claim 1, wherein the at least one processor is further configured to cause the first UE to transmit, in a second physical uplink control channel (PUCCH) resource, the HARQ feedback indicating a delay in receiving the PSFCH in response to a physical sidelink feedback channel (PSFCH) not being received from the second UE via the one or more SL resources before the first PUCCH resource is to transmit the HARQ feedback to the base station.

12. The at least one processor, in the first UE, receiving a non-numeric HARQ feedback indicator from the base station; receiving a trigger to request the HARQ feedback from the base station after receiving the non-numeric HARQ feedback indicator; 10. The first UE of claim 1, further configured to: transmit the SL HARQ feedback to the base station in response to the trigger.

13. The at least one processor, in the first UE, receiving, as part of the first control signaling from the base station, an indication of a start of a channel occupation (CO) duration for transmission on the one or more associated SL resources; performing autonomous resource selection to acquire resources for the first SL grant during a time gap indicated by the start of the CO duration.

14. A base station for wireless communications, comprising: At least one memory; and at least one processor coupled to the at least one memory, the at least one processor causing the base station to: transmitting, to a user equipment (UE), first control signaling indicating a first backlink (SL) grant having one or more associated SL resources; and receiving a negative acknowledgement (NACK) during a hybrid automatic repeat request (HARQ) in a first physical uplink control channel (PUCCH) resource from the UE if clear channel assessment (CCA) fails for the one or more associated SL resources.

15. The at least one processor, in the base station, transmitting a non-numeric HARQ feedback indicator to the UE; sending a trigger to the UE to request the HARQ feedback after sending the non-numeric HARQ feedback indicator; and receiving the HARQ feedback from the UE in response to the trigger.

16. A method implemented by a user equipment (UE), comprising: receiving, from a base station, first control signaling indicating a first SL grant having one or more associated SL resources; performing CCA for the one or more associated SL resources; including a negative acknowledgement (NACK) in hybrid automatic repeat request (HARQ) feedback in response to the CCA failing for the one or more SL resources; transmitting the HARQ feedback to the base station.

17. The method described in claim 16, further comprising a step of performing autonomous resource selection to obtain resources for the first SL grant in response to determining that the one or more SL resources are not included in the first SL grant or that the one or more SL resources are outside of remaining channel occupancy (CO).

18. A processor for wireless communications, comprising: at least one controller coupled to at least one memory, the controller causing the processor to: receiving, from a base station, first control signaling indicating a first sidelink (SL) grant having one or more associated SL resources; performing a clear channel assessment (CCA) for the one or more associated SL resources; including a negative acknowledgement (NACK) in hybrid automatic repeat request (HARQ) feedback in response to the CCA failing for the one or more SL resources; and transmitting the HARQ feedback to the base station. Processor.

19. The at least one controller, in response to a physical sidelink feedback channel (PSFCH) not being received from a user equipment (UE) via the one or more SL resources before a physical uplink control channel (PUCCH) resource is to transmit the HARQ feedback to the base station, causes the processor to: transmitting the NACK in the HARQ feedback; receiving second control signaling from the base station indicating a second SL grant; and ignoring the second SL grant in response to the PSFCH being received from the UE via the one or more SL resources after the HARQ feedback has been transmitted to the base station.

20. The processor of claim 18.

20. The one or more controllers, in response to the CCA failing for the one or more SL resources, cause the processor to: and further configured to cause receiving a second SL grant from the base station in response to the HARQ feedback.

20. The processor of claim 18.

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