Patent Description:
3GPP document R1- <NUM> "<NPL>, discloses <NUM> alternatives for transmission of HARQ feedback corresponding to PDSCHs outside of the channel occupancy of the PDSCHs: gNB requests/triggers feedback for PDSCH from earlier COT(s), UE is configured to report HARQ feedback for PDSCH from earlier COT(s) without an explicit request/trigger, and PDSCH-to-HARQ-timing indicator is used in the DCI scheduling the PDSCH.

3GPP document R1-<NUM>, "<NPL>, discloses multiple / supplemental transmission opportunities for HARQ feedback and <NUM> alternatives to report HARQ feedback outside of the same channel occupancy: gNB requests/triggers feedback for PDSCH from earlier COT(s), UE is configured to report HARQ feedback for PDSCH from earlier COT(s) without an explicit request/trigger, and PDSCH-to-HARQ-timing indicator is used in the DCI scheduling the PDSCH.

For example, a fifth generation (<NUM>) wireless communications technology (which may be referred to as new radio (NR)) is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, <NUM> communications technology may include: enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with certain specifications for latency and reliability; and massive machine type communications, which may allow a very large number of connected devices and transmission of a relatively low volume of non-delay-sensitive information. As the demand for mobile broadband access continues to increase, however, further improvements in NR communications technology and beyond may be desired.

Independent claim <NUM> defines a method of wireless communication by a receiving user equipment according to the invention. Independent claim <NUM> defines the corresponding receiving user equipment according to the invention.

In the following, each of the described methods, apparatuses, examples, and aspects which do not fully correspond to the invention as defined in the claims is thus not according to the invention and is, as well as the whole following description, present for illustration purposes only or to highlight specific aspects or features of the claims.

Conventionally, new radio (NR) sidelink communications (e.g., NR vehicle-to-everything (V2X) communications) are designed to use licensed spectrums such as shared cellular bands or dedicated spectrum for intelligent transportation system (ITS) for communications. However, licensed spectrums may not be guaranteed in some regions. In these situations, NR V2X may use unlicensed spectrum shared by other technologies (e.g., Wi-Fi) to obtain additional bandwidth not provided by the licensed spectrum. However, unlicensed spectrums may be subject to regulatory requirements. One of the requirements includes listen-before-talk (LBT) techniques requiring a device to perform sensing (e.g., listen) before the device can transmit (e.g., talk). In LBT, a device may measure energy in a band and transmit if the energy is below a threshold. LBT includes different types of regulations including, for example, category (CAT) <NUM> LBT which does not include random back-off and CAT <NUM> LBT, which includes random back-off with a contention window of variable size. However, use of LBT may create uncertainty and add time delays for acknowledging data transmissions.

The present disclosure provides for cross channel occupancy time ((COT), or referred to as channel occupancy, (CO)) hybrid automatic repeat request (HARQ) feedback transmission for sidelink communication in unlicensed spectrum, which may improve success probability of HARQ feedback transmissions.

In more detail, NR V2X sidelink HARQ feedback mechanisms in licensed spectrums may include, for example, a first user equipment (UE1) that transmits a data channel, a second UE (UE2) that receives the transmission and sends an acknowledgment / negative acknowledgment (ACK/NACK) to indicate whether the data is successfully decoded. HARQ feedback transmissions may occur in a configured or pre-configured physical sidelink feedback channel (PSFCH) resource, which occurs in every N slots, where the feedback periodicity N = <NUM>, <NUM>, or <NUM>. For example N = <NUM> means feedback opportunity in every slot (e.g., every slot has a resource configured for HARQ feedback transmission), N = <NUM> means feedback opportunity in every other slot, and N = <NUM> means feedback opportunity in every <NUM> slots.

The resource used for HARQ feedback transmission corresponding to a physical sidelink shared channel (PSSCH) is determined based on a time and a frequency location of the transmission and a transmitter UE identification (ID), and a receiver UE ID if the HARQ feedback is for ACK/NACK based groupcast communications.

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

In an aspect, NR V2X for licensed spectrums may support autonomous resource allocation (e.g., Mode <NUM>). In this example, a UE can access the channel based on V2X channel sensing by the UE. Specifically, the UE may first identify available resources for sidelink transmission (e.g., candidate resources) by the UE. The UE may then select resources for transmissions from the candidate resources. Resource selection and reservation in autonomous resource allocation may include reservations of up to two future resources, in addition to a current resource, for the UE's transmission (e.g., for retransmission of a packet) when transmitting the current transmission. For resource reservation, the UE may select resources from candidate resources. When transmitting a PSSCH, the UE's sidelink control indicator (SCI) transmission may indicate resource allocation for the current transmission. The SCI also may indicate one or more future resources, which may be used by the UE to perform retransmission(s) or to transmit different data packets. In some examples, the resource reservations can be chained.

In an aspect, NR - unlicensed (NR-U) may specify a Type <NUM> or a Type <NUM> channel access type. In the Type <NUM> channel access, time duration spanned by the sensing slots that are sensed to be idle before a transmission(s) may be random (e.g., CAT <NUM> LBT). In an example, the channel access by Type <NUM> channel access may include channel sensing or energy detection performed in a random number of sensing slots. In the Type <NUM> channel access, time duration spanned by sensing slots that are sensed to be idle before a transmission(s) is determined based on a Type 2A having a sensing duration of <NUM> microseconds (µs), a Type 2B having a sensing duration of <NUM>, or a Type 2C having no sensing duration (e.g., may be applied when a gap between two transmissions is no larger than <NUM>). Typically, Type <NUM> channel access requires less operations than a Type <NUM> channel access.

In another aspect of NR-U, a base station may initiate a channel occupancy time (COT) or channel occupancy (CO) based on a Type <NUM> channel access. The base station may share the COT with other UEs, such that the UE may perform Type <NUM> channel access before intended transmissions in the COT, and the UE may transmit if the Type <NUM> channel access is successful.

In an aspect, HARQ feedback-based retransmissions may improve system performance. For example, retransmission(s) based on NACK feedback may guarantee that a packet is successfully delivered to intended receivers. Compared to blind retransmission (e.g., the packet is blindly transmitted multiple times without HARQ feedback mechanism), HARQ feedback-based retransmission may improve spectral efficiency. However, for sidelink communications in the unlicensed spectrum, HARQ feedback transmission may be subject to availability of the channel because the unlicensed spectrum is shared with other radio access technologies. Due to the uncertain channel availability in the unlicensed spectrum, HARQ feedback transmissions taking place in certain or known slots (such as in the pre-configured HARQ feedback occasions depending on a configuration of the feedback periodicity N and HARQ feedback processing timeline), may not be guaranteed. For example, a sidelink receiving UE receiving a sidelink data channel transmission in slot n may not be able to transmit HARQ feedback until slot n+k, where k is a HARQ feedback processing timeline which may be greater than or equal to <NUM> slot; however, the availability of slot n+k for HARQ feedback may be subject to e.g., LBT. Further, a COT shared by UEs for sidelink communications may have a limitation (e.g., <NUM> milliseconds (ms) / <NUM> slots).

Due to HARQ timeline limitations and COT duration limitations, sidelink data channel transmissions in the last one or multiple slots of a COT may not have a same-COT HARQ feedback resource available (e.g., see COT duration of <FIG>). For example, for PSSCH transmissions taking place in the last few slots of the COT, there may not be HARQ feedback resources available for corresponding HARQ feedback transmissions in the same COT, due to the HARQ processing timeline (e.g., gap between PSSCH and PSFCH transmissions).

Accordingly, this present disclosure proposes HARQ feedback techniques that may improve the availability of the medium for HARQ feedback transmission, while, at the same time, without requiring the reduction of the receiving UE HARQ feedback processing time.

For a UE receiving a sidelink data channel transmission, the receiving UE may determine a first slot (or first PSFCH occasion) to transmit a HARQ feedback to acknowledge data channel, based on a PSFCH resource configuration and a HARQ timeline. If the receiving UE determines that the first PSFCH occasion is within the same active COT that the sidelink data channel has been received, the receiving UE may perform a HARQ feedback transmission following a regular HARQ feedback transmission procedure (e.g., perform Type <NUM> channel access for the HARQ feedback transmission).

However, if the receiving UE determines that the first PSFCH occasion is out of the first COT, for example, in a slot of the first COT but the first COT is no longer active in that slot (e.g., the first COT has been released at or prior to the slot) or a slot that is after the last slot of the first COT due to COT duration limitation, the UE may transmit the HARQ feedback based on four options. In Option <NUM>, the receiving UE may determine that the first PSFCH occasion is in a slot of another active COT, which is initiated by either the receiving UE, the UE transmitting the PSSCH, or another UE. In Option <NUM>, the receiving UE may transmit a HARQ feedback in the determined HARQ occasion (e.g., following a successful Type <NUM> channel access). In Option <NUM>, the receiving UE may determine that there is a second COT that is active and adjacent to the first COT. In Option <NUM>, the receiving UE may determine a second PSFCH occasion in the second COT to transmit the HARQ feedback (e.g., the second PSFCH occasion may be the same as or different from the first PSFCH occasion). In Option <NUM>, the receiving UE may perform a Type <NUM> channel access prior to the first PSFCH occasion, and transmit a HARQ feedback in the first PSFCH occasion if the receiving UE succeeds the Type <NUM> channel access (i.e., the Type <NUM> channel access indicates an idle channel for the transmission). In Option <NUM>, the receiving UE may determine that a total number of transmissions of PSFCH during a time window is smaller than a threshold value, and/or, a total duration of the transmissions of PSFCH during the time window is smaller than a threshold value, and the receiving UE may transmit the HARQ feedback in the first PSFCH occasion.

Storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may comprise a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that may be used to store computer executable code in the form of instructions or data structures that may be accessed by a computer.

Turning now to the figures, examples of systems, apparatus, and methods according to aspects of the present disclosure are depicted. It is to be understood that aspects of the figures may not be drawn to scale and are instead drawn for illustrative purposes.

The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes at least one base station <NUM>, UEs <NUM>, an Evolved Packet Core (EPC) <NUM>, and a <NUM> Core (5GC) <NUM>. The base station <NUM> may include macro cells (high power cellular base station) and/or small cells (low power cellular base station).

In some implementations, UEs <NUM> may include a modem <NUM> and/or a sidelink HARQ component <NUM> for channel access for sidelink HARQ feedback transmissions in an unlicensed spectrum.

A base station <NUM> may be configured for <NUM> LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC <NUM> through backhaul links interfaces <NUM> (e.g., S1, X2, Internet Protocol (IP), or flex interfaces). A base station <NUM> configured for <NUM> NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with 5GC <NUM> through backhaul links interfaces <NUM> (e.g., S1, X2, Internet Protocol (IP), or flex interface). In addition to other functions, the base station <NUM> may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base station <NUM> may communicate directly or indirectly (e.g., through the EPC <NUM> or 5GC <NUM>) with each other over the backhaul links interfaces <NUM>. The backhaul links <NUM>, <NUM> may be wired or wireless.

The base station <NUM> may wirelessly communicate with the UEs <NUM>. Each of the base station <NUM> may provide communication coverage for a respective geographic coverage area <NUM>. For example, the small cell <NUM>' may have a coverage area <NUM>' that overlaps the coverage area <NUM> of one or more macro base station <NUM>. A network that includes both small cell and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node base station (eNBs) (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG). The communication links <NUM> between the base station <NUM> and the UEs <NUM> may include uplink (UL) (also referred to as reverse link) transmissions from a UE <NUM> to a base station <NUM> and/or downlink (DL) (also referred to as forward link) transmissions from a base station <NUM> to a UE <NUM>. The base station <NUM> / UEs <NUM> may use spectrum up to Y MHz (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL).

A base station <NUM>, whether a small cell <NUM>' or a large cell (e.g., macro base station), may include an eNB, gNodeB (gNB), or other type of base station. Extremely high frequency (EHF) is part of the radio frequency (RF) in the electromagnetic spectrum. The mmW base station <NUM> may utilize beamforming <NUM> with the UE <NUM> to compensate for the path loss and short range.

The MBMS Gateway <NUM> may be used to distribute MBMS traffic to the base station <NUM> belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The 5GC <NUM> may include a Access and Mobility Management Function (AMF) <NUM>, other AMFs <NUM>, a Session Management Function (SMF) <NUM>, and a User Plane Function (UPF) <NUM>. The AMF <NUM> is the control node that processes the signaling between the UEs <NUM> and the 5GC <NUM>.

The base station <NUM> may also be referred to as a gNB, Node B, evolved Node B (eNB), an access point, a base transceiver station, a radio base station, an access point, an access node, a radio transceiver, a NodeB, eNodeB (eNB), gNB, Home NodeB, a Home eNodeB, a relay, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. The base station <NUM> provides an access point to the EPC <NUM> or 5GC <NUM> for a UE <NUM>.

Referring to <FIG>, an example implementation of the UE <NUM> may include the modem <NUM> having the sidelink HARQ component <NUM>. The modem <NUM> and/or the sidelink HARQ component <NUM> of the UE <NUM> may be configured to manage communications with other UEs via a cellular network, a Wi-Fi network, or other wireless and wired networks using licensed and/or unlicensed spectrums.

In some implementations, the UE <NUM> may include a variety of components, including components such as one or more processors <NUM> and memory <NUM> and transceiver <NUM> in communication via one or more buses <NUM>, which may operate in conjunction with the modem <NUM> and/or the sidelink HARQ component <NUM> to enable one or more of the functions described herein related to sidelink HARQ transmissions. Further, the one or more processors <NUM>, modem <NUM>, memory <NUM>, transceiver <NUM>, RF front end <NUM> and one or more antennas <NUM>, may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies. The one or more antennas <NUM> may include one or more antennas, antenna elements and/or antenna arrays.

In an aspect, the one or more processors <NUM> may include the modem <NUM> that uses one or more modem processors. The various functions related to the sidelink HARQ component <NUM> may be included in the modem <NUM> and/or the processors <NUM> and, in an aspect, may be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors <NUM> may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiving device processor, or a transceiver processor associated with transceiver <NUM>. Additionally, the modem <NUM> may configure the UE <NUM> along with the processors <NUM>. In other aspects, some of the features of the one or more processors <NUM> and/or the modem <NUM> associated with the sidelink HARQ component <NUM> may be performed by the transceiver <NUM>.

Also, the memory <NUM> may be configured to store data used herein and/or local versions of applications <NUM> or the sidelink HARQ component <NUM> and/or one or more subcomponents of the sidelink HARQ component <NUM> being executed by at least one processor <NUM>. The memory <NUM> may include any type of computer-readable medium usable by a computer or at least one processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, the memory <NUM> may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining the sidelink HARQ component <NUM> and/or one or more of its subcomponents, and/or data associated therewith, when the UE <NUM> is operating at least one processor <NUM> to execute the sidelink HARQ component <NUM> and/or one or more of the subcomponents.

The transceiver <NUM> may include at least one receiver <NUM> and at least one transmitter <NUM>. The receiver <NUM> may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). The receiver <NUM> may be, for example, an RF receiving device. In an aspect, the receiver <NUM> may receive signals transmitted by at least one base station <NUM>. The transmitter <NUM> may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). A suitable example of the transmitter <NUM> may include, but is not limited to, an RF transmitter.

Moreover, in an aspect, the UE <NUM> may include the RF front end <NUM>, which may operate in communication with one or more antennas <NUM> and the transceiver <NUM> for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station <NUM> or wireless transmissions transmitted by the UE <NUM>. The RF front end <NUM> may be coupled with one or more antennas <NUM> and may include one or more low-noise amplifiers (LNAs) <NUM>, one or more switches <NUM>, one or more power amplifiers (PAs) <NUM>, and one or more filters <NUM> for transmitting and receiving RF signals.

In an aspect, the LNA <NUM> may amplify a received signal at a desired output level. In an aspect, each of the LNAs <NUM> may have a specified minimum and maximum gain values. In an aspect, the RF front end <NUM> may use one or more switches <NUM> to select a particular LNA <NUM> and the specified gain value based on a desired gain value for a particular application.

Further, for example, one or more PA(s) <NUM> may be used by the RF front end <NUM> to amplify a signal for an RF output at a desired output power level. In an aspect, each of the PAs <NUM> may have specified minimum and maximum gain values. In an aspect, the RF front end <NUM> may use one or more switches <NUM> to select a particular PA <NUM> and the specified gain value based on a desired gain value for a particular application.

Also, for example, one or more filters <NUM> may be used by the RF front end <NUM> to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter <NUM> may be used to filter an output from a respective PA <NUM> to produce an output signal for transmission. In an aspect, each filter <NUM> may be coupled with a specific LNA <NUM> and/or PA <NUM>. In an aspect, the RF front end <NUM> may use one or more switches <NUM> to select a transmit or receive path using a specified filter <NUM>, the LNA <NUM>, and/or the PA <NUM>, based on a configuration as specified by the transceiver <NUM> and/or processor <NUM>.

As such, the transceiver <NUM> may be configured to transmit and receive wireless signals through one or more antennas <NUM> via the RF front end <NUM>. In an aspect, the transceiver <NUM> may be tuned to operate at specified frequencies such that the UE <NUM> may communicate with, for example, one or more of the base stations <NUM> or one or more cells associated with one or more of the base stations <NUM>. In an aspect, for example, the modem <NUM> may configure the transceiver <NUM> to operate at a specified frequency and power level based on a UE configuration of the UE <NUM> and the communication protocol used by the modem <NUM>.

In an aspect, the modem <NUM> may be a multiband-multimode modem, which may process digital data and communicate with the transceiver <NUM> such that the digital data is sent and received using the transceiver <NUM>. In an aspect, the modem <NUM> may be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, the modem <NUM> may be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, the modem <NUM> may control one or more components of the UE <NUM> (e.g., RF front end <NUM>, transceiver <NUM>) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, a modem configuration may be based on the mode of the modem <NUM> and the frequency band in use. In another aspect, the modem configuration may be based on UE configuration information associated with the UE <NUM> as provided by the network (e.g., base station <NUM>).

Referring to <FIG>, a single slot format <NUM> for an NR V2X communication is provided. In an example, the slot format <NUM> may include <NUM> symbols including a portion for a physical sidelink control channel (PSCCH) <NUM> used, for example, for carrying control signals, a portion for the PSSCH <NUM> used, for example, for carrying data signals, one or more gaps <NUM>, and the PSFCH <NUM> used, for example, for carrying feedback signals (e.g., HARQ ACK/NACK). Each slot <NUM> of a plurality of slots <NUM> may be divided into frequency PRB <NUM> or sub-channel; PSFCH resources in a PSFCH slot may consist of a set of PRBs <NUM>. In NR V2X, one PSFCH may be transmitted using one PRB <NUM>, with a certain code domain resource (cyclic shift (CS)).

Referring to <FIG>, an example of a series of slots <NUM> for NR V2X communications is provided. As illustrated, the series of slots <NUM> may initiate with slot n, and increase until n+m slots, where m is any whole number. As described herein, feedback may be based on the feedback periodicity N, and the processing time of a receiving UE <NUM> to decode a received transmission. As shown by the series of slots <NUM>, if N = <NUM> (i.e., feedback opportunities are in every other slot) and k = <NUM> (i.e., two slots are needed for the processing time of the receiving UE <NUM> to decode the transmission and process the HARQ feedback), a feedback occasion may not occur until every other slot.

Referring to <FIG>, an example COT <NUM> including a duration of <NUM> slots (e.g., Slot n - Slot n+<NUM>) is depicted. However, in other examples the COT may have a duration less than or greater than <NUM> slots.

As described herein, the feedback periodicity N may be set to different periodicities including, for example, the N=<NUM> such that the PFSCH occasion <NUM> (or HARQ occasion) is every other slot, as illustrated by <FIG>. As described herein, due to HARQ timeline limitations and COT duration limitations, sidelink data channel transmissions in a last single slot or multiple last slots of a COT may not have a same-COT HARQ feedback resource available. For example, if N = <NUM> and k = <NUM> (i.e., at least two slots are needed for the receiving UE <NUM> to decode a transmission and process HARQ feedback), as illustrated by <FIG>, when a PSSCH is transmitted in slot n, the first HARQ occasion satisfying the timeline is slot n+<NUM>, so a HARQ feedback for the PSSCH may be transmitted in slot n+<NUM>. However, if a PSSCH is transmitted in slot n+<NUM> (or slot n+<NUM>), the corresponding HARQ feedback is mapped to slot n+<NUM> which is not included in the same COT because the COT ends at slot n+<NUM>. Accordingly, the present disclosure provides techniques for cross COT HARQ feedback transmission.

Referring to <FIG>, an example of a first feedback technique <NUM> (e.g., Option <NUM> described above) is provided. As illustrated, two active COTs, a first active COT <NUM> and a second active COT <NUM> may be available. COTs <NUM> and <NUM> may be examples of the COT <NUM>.

In the first feedback technique <NUM>, the receiving UE <NUM> may determine that a first PSFCH occasion <NUM> (e.g., first available PSFCH to transmit HARQ feedback based on the feedback periodicity N and processing time for the receiving UE <NUM> to decode a PSSCH transmission) is outside of the first active COT <NUM>. For example, the UE may determine that the feedback should be transmitted in slot n+<NUM>, which outside of the first active COT <NUM> (e.g., current COT). However, based on sidelink decoding (e.g., the UE decoded information of a second active COT <NUM> from sidelink transmissions in slot n+<NUM>), the UE realizes that slot n+<NUM> is included in the second active COT <NUM>, so the UE can still transmit HARQ feedback in slot n+<NUM>. In response to this determination, the receiving UE <NUM> may determine the first PSFCH occasion <NUM> in a slot of the second active COT <NUM> is available for sending a HARQ feedback <NUM>. The receiving UE <NUM> may transmit the HARQ feedback <NUM>, as feedback to the PSSCH transmission received in the slot n+<NUM> or slot n+<NUM> of the first active COT <NUM>, in the first PSFCH occasion <NUM> (e.g., following a successful Type <NUM> channel access). In an example, the second active COT <NUM> may be initiated by either the receiving UE <NUM> or another UE <NUM> during channel access. Thus, the receiving UE <NUM> may transmit the HARQ feedback <NUM> if the first PSFCH occasion <NUM> is in the second active COT <NUM>. In an example, the receiving UE <NUM> may transmit the HARQ feedback <NUM> if the receiving UE <NUM> is allowed to transmit (e.g., the receiving UE <NUM> determines that it can share the second COT <NUM>). The receiving UE <NUM> may determine that it is allowed to transmit, for example, based on decoded COT information (e.g., from decoding sidelink transmissions in slot n+<NUM>), which indicates the COT is a shared COT. In another example, the receiving UE <NUM> may transmit the HARQ feedback <NUM> if a channel access (e.g., Type <NUM> channel access) is successful prior to the HARQ feedback <NUM> transmission.

As an example, as illustrated by <FIG>, the first active COT <NUM> ends at slot n+<NUM> and feedback periodicity N=<NUM>. For a data channel transmission in slot n+<NUM> or slot n+<NUM>, the PSFCH occasion <NUM> is determined to be in slot n+<NUM>. The receiving UE <NUM> may determine that slot n+<NUM> is in the second active COT <NUM> (which is initiated at slot n+<NUM>), so the receiving UE <NUM> may transmit the HARQ feedback <NUM> in the determined PSFCH occasion <NUM>.

Referring to <FIG>, a second feedback technique <NUM> (e.g., Option <NUM> described above) is provided according to the claimed invention.

As illustrated, two active COTs, a first active COT <NUM> and a second active COT <NUM> (including slot p - slot p+<NUM>) are available. COTs <NUM> and <NUM> may be examples of the COT <NUM>.

In the second feedback technique <NUM>, the receiving UE <NUM> determines that a PSFCH occasion is out of the first active COT <NUM> and transmits a HARQ feedback <NUM> in the second active COT <NUM> if the second active COT <NUM> is adjacent to the first active COT <NUM>. In an example, the second active COT <NUM> may be initiated by the receiving UE <NUM>, or another UE.

In this technique, "adjacent" may include one or more of the following characteristics: the two COTs <NUM> and <NUM> are initiated by the receiving UE <NUM> (i.e., the same UE); the two COTs <NUM> and <NUM> are initiated by two UEs (e.g., receiving UE <NUM> and a second UE) that are within a range threshold (e.g., distance between COT initiators based on initiator locations as indicated by COT information) of each other; a distance such as absolute distance (e.g., meters) or RF distance (e.g., reference signal receive power (RSRP)) to an initiator UE of the second active COT <NUM> or initiator UE(s) of both COTs <NUM> and <NUM> is within a distance threshold; or a gap <NUM> (e.g., duration from ending of the first active COT <NUM> to beginning of the second active COT <NUM>) between the two COTs <NUM> and <NUM> has a duration that is smaller than a threshold.

In an example, as illustrated by <FIG>, the first active COT <NUM> ends at slot n+<NUM>. For a data channel transmission in slot n+<NUM>, the PSFCH occasion is determined to be slot n+<NUM>, which is not in the first active COT <NUM>. The receiving UE <NUM> may determine that there is a second active COT <NUM> that is adjacent to the first active COT <NUM>, based on the characteristics described herein. The receiving UE <NUM> may determine a second PSFCH occasion <NUM> in the second active COT <NUM> to transmit the HARQ feedback <NUM>.

While this example describes the second PSFCH occasion <NUM> being different than a first PSFCH occasion, according to the claimed invention, the second PSFCH occasion <NUM> is the same as the first PSFCH occasion. In an aspect, the second feedback technique <NUM> may include a Type <NUM> channel access for HARQ feedback transmissions.

Referring to <FIG>, an example of a third feedback technique <NUM> (e.g., Option <NUM> described above) is provided. As illustrated, a first active COT <NUM> may be available. COT <NUM> may be examples of the COT <NUM>.

In the third feedback technique <NUM>, the receiving UE <NUM> may perform a Type <NUM> channel access (e.g., random back-off within a contention window) prior to the first PSFCH occasion <NUM> (or a HARQ feedback <NUM>), and transmit the HARQ feedback <NUM> in the first PSFCH occasion <NUM> if the receiving UE <NUM> succeeds with the Type <NUM> channel access (e.g., the Type <NUM> channel access indicates to the receiving UE <NUM> an idle channel for transmission). In an example, the UE may perform Type <NUM> channel access for the HARQ feedback <NUM> transmission irrespective of the PSFCH occasion <NUM> being in an active COT or not, and the HARQ feedback may be transmitted if the Type <NUM> channel access is successful. In another example, the UE may perform Type <NUM> channel access for HARQ feedback transmission if the PSFCH occasion <NUM> is not in an active COT; the HARQ feedback <NUM> may be transmitted if the Type <NUM> channel access is successful.

As an example, and as illustrated by <FIG>, the first active COT <NUM> may end at slot n+<NUM>. For a data channel transmission in slot n+<NUM>, the PSFCH occasion <NUM> may be determined to be slot n+<NUM>. The receiving UE <NUM> may determine that slot n+<NUM> is not in the first active COT <NUM> and therefore perform a Type <NUM> channel access for the HARQ feedback <NUM> transmission in slot n+<NUM>. The receiving UE <NUM> may transmit the HARQ feedback <NUM> in slot n+<NUM> if the Type <NUM> channel access succeeds.

Referring to <FIG>, a fourth feedback technique <NUM> (e.g., Option <NUM> described above) is provided according to the claimed invention.

As illustrated, a first active COT <NUM> may be available. The COT <NUM> may be an example of the COT <NUM>.

In the fourth feedback technique <NUM>, the receiving UE <NUM> determines that a PSFCH occasion <NUM> is out of the first active COT <NUM>, and in response to the determination, determines whether a total number of HARQ feedbacks <NUM> and <NUM> within a time window <NUM> is less than a transmission number threshold, and/or determines a total duration of HARQ feedbacks <NUM> and <NUM> in the time window <NUM> is less than a transmission duration threshold. In this example, the HARQ feedbacks <NUM> may represent HARQ feedback transmissions that the receiving UE <NUM> is going to transmit, and the HARQ feedbacks <NUM> may represent already transmitted HARQ feedback transmissions.

According to the claimed invention, if one or more of the thresholds are met, the receiving UE transmits the HARQ feedback <NUM> in the first PSFCH occasion <NUM>. In an example, the time window <NUM> may include a past window of time (e.g., look-back window) set at a determined duration of time (e.g., <NUM>). In an example, the time window <NUM> may include the first PSFCH occasion <NUM>, as illustrated by <FIG>. However, in other examples, the first PSFCH occasion <NUM> may not be included in the time window <NUM>.

In an example, the total number of HARQ feedbacks <NUM> and <NUM> may include any transmission that the receiving UE <NUM> transmits in a PSFCH occasion during the time window <NUM>. In an example, the total duration of the HARQ feedbacks <NUM> and <NUM> in the time window <NUM> may include a duration of each HARQ feedback <NUM> and <NUM> during the time window <NUM>.

In an example, the transmission number threshold and the transmission duration threshold may be pre-determined (e.g., configured, pre-configured, or pre-defined by the receiving UE <NUM>). In an example, the transmission number threshold may be <NUM> for a time window <NUM> of <NUM>, and the transmission duration threshold may be <NUM> for the time window <NUM> of <NUM>.

In an aspect, the fourth feedback technique <NUM> may include a PSFCH transmission that is LBT-free. For example, the UE may transmit HARQ feedback based on Type <NUM>-C channel access.

In an aspect, a global PSFCH resource configuration (e.g., PSFCH <NUM>) may be determined based on a periodicity (e.g., feedback periodicity N and a global slot index (e.g., slot index representing physical slot, or slot in a sidelink resource pool). For example, a HARQ timeline may be n+<NUM> and a PSFCH slot period may be N=<NUM> based on slot index in a sidelink resource pool. In another aspect, a COT-specific PSFCH resource configuration may be based on the periodicity (e.g., feedback periodicity N) and a slot index within the COT. For example, a HARQ timeline may be n+<NUM> and a PSFCH slot period may be N=<NUM> within a COT.

In an aspect, different techniques may be applied based on different conditions determined by the receiving UE <NUM>. For example, the third feedback technique <NUM> may be applied if conditions for the fourth feedback technique <NUM> are unable to be satisfied. In another example, the third feedback technique <NUM> may be applied if conditions for the first feedback technique <NUM> or the second feedback technique <NUM> are unable to be satisfied. In another example, the second feedback technique <NUM> may be applied if conditions for the first feedback technique <NUM> are unable to be satisfied.

Referring to <FIG>, an example of a method <NUM> for sidelink HARQ feedback transmissions in unlicensed spectrums may be performed by the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, the memory <NUM>, and or any other component/subcomponent of the receiving UE <NUM> of the wireless communication network <NUM>.

At block <NUM>, the method <NUM> may include receiving, from a transmitting UE, a first transmission in a first COT. For example, the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, and/or one or more additional components/subcomponents of the UE <NUM> may be configured to or may comprise means for receiving, from a transmitting UE, a first transmission in a first COT.

For example, the receiving of the first transmission at the block <NUM> may include receiving by the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, via the antenna <NUM>, the RF front end <NUM>, and/or the transceiver <NUM>, a data transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> of <FIG>, the first COT <NUM> of <FIG>, the first COT <NUM> of <FIG>, or the first COT <NUM> of <FIG> from a transmitting UE <NUM>.

At block <NUM>, the method <NUM> may include determining, in response to the receiving of the first transmission, a first feedback occasion is outside of the first COT. For example, the sidelink HARQ component <NUM>, the modem <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, and/or one or more additional components/subcomponents of the UE <NUM> may be configured to or may comprise means for determining a first feedback occasion is outside of the first COT.

For example, the determining the first feedback occasion is outside of the first COT at block <NUM> may include determining by the sidelink HARQ component <NUM>, the modem <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM> the first feedback occasion <NUM> of <FIG> is after the last slot n+<NUM> of the first COT <NUM>, the first feedback occasion (e.g., slot n+<NUM>) of <FIG> is after the last slot n+<NUM> of the first COT <NUM>, the first feedback occasion <NUM> of <FIG> is after the last slot n+<NUM> of the first COT <NUM>, or the first feedback occasion <NUM> of <FIG> is after the last slot n+<NUM> of the first COT <NUM>.

In an example, the first feedback occasion may be determined based on the feedback periodicity N and a global slot index (e.g., n - n+<NUM>), or the feedback periodicity N and a slot index of the second COT (e.g., n+<NUM>, or p - p+<NUM>).

At block <NUM>, the method <NUM> may include determining, in response to determining the first feedback occasion is after the last slot of the first COT, one or more feedback configurations. For example, the sidelink HARQ component <NUM>, the modem <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, and/or one or more additional components/subcomponents of the UE <NUM> may be configured to or may comprise means for determining one or more feedback configurations.

For example, the determining the one or more feedback configurations may include determining by the sidelink HARQ component <NUM>, the modem <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM> the first feedback occasion <NUM> of <FIG> is in an active second COT <NUM>, the a feedback occasion <NUM> of <FIG> is in an adjacent COT <NUM>, a successful Type <NUM> channel access was performed prior to the first feedback occasion <NUM> of <FIG>, or a total number of feedback transmissions <NUM> and/or <NUM> (or a total duration of the feedback transmission <NUM> and/or <NUM>) is less than a threshold (e.g., transmission number threshold or transmission duration threshold).

At block <NUM>, the method <NUM> may include transmitting, to the transmitting UE, a feedback message indicating decoding of the first transmission in the first feedback occasion or a second feedback occasion based on the one or more feedback configurations. For example, the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, and/or one or more additional components/subcomponents of the UE <NUM> may be configured to or may comprise means for transmitting, to the transmitting UE, a feedback message indicating decoding of the first transmission in the first feedback occasion or a second feedback occasion based on the one or more feedback configurations.

For example, the transmitting at block <NUM> may include transmitting by the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, via the antenna <NUM>, the RF front end <NUM>, and/or the transceiver <NUM>, to the transmitting UE <NUM>, the HARQ feedback <NUM> of <FIG> indicating decoding of the first transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> in the first feedback occasion <NUM> of the second COT <NUM> based on the one or more feedback configurations (e.g., determining the second COT <NUM> is an active COT), the HARQ feedback <NUM> of <FIG> indicating decoding of the first transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> in the feedback occasion <NUM> (first or second feedback occasion) of the second COT <NUM> based on the one or more feedback configurations (e.g., determining the second COT <NUM> is adjacent to the first COT <NUM>), the HARQ feedback <NUM> of <FIG> indicating decoding of the first transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> in the first feedback occasion <NUM> based on the one or more feedback configurations (e.g., determining a Type <NUM> channel access was successful prior to the first feedback occasion <NUM>), or the HARQ feedback <NUM> of <FIG> indicating decoding of the first transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> in the first feedback occasion <NUM> based on the one or more feedback configurations (e.g., determining the total number of feedback transmissions is less than a transmission number threshold or determining the total duration of feedback transmissions is less than a transmission duration threshold).

Referring to <FIG>, an example of a method <NUM> for sidelink HARQ feedback transmissions in unlicensed spectrums may be performed by the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, the memory <NUM>, and or any other component/subcomponent of the transmitting UE <NUM> of the wireless communication network <NUM>.

At block <NUM>, the method <NUM> may include transmitting, to a receiving UE, a first transmission in a first COT. For example, the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, and/or one or more additional components/subcomponents of the UE <NUM> may be configured to or may comprise means for transmitting, to a receiving UE, a first transmission in a first COT.

For example, the transmitting of the first transmission at the block <NUM> may include transmitting, to a receiving UE <NUM>, a data transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> of <FIG>, the first COT <NUM> of <FIG>, the first COT <NUM> of <FIG>, or the first COT <NUM> of <FIG> from a transmitting UE <NUM>.

At block <NUM>, the method <NUM> may include receiving, from the receiving UE, a feedback message indicating decoding of the first transmission in a feedback occasion after a last slot of the first COT based on one or more feedback configurations. For example, the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, and/or one or more additional components/subcomponents of the UE <NUM> may be configured to or may comprise means for receiving, from the receiving UE, a feedback message indicating decoding of the first transmission in a feedback occasion after a last slot of the first COT based on one or more feedback configurations.

For example, the receiving at block <NUM> may include receiving by the sidelink HARQ component <NUM>, the modem <NUM>, the transceiver <NUM>, the processor <NUM>, and/or the memory <NUM> of the UE <NUM>, via the antenna <NUM>, the RF front end <NUM>, and/or the transceiver <NUM>, from the receiving UE <NUM>, the HARQ feedback <NUM> of <FIG> indicating decoding of the first transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> in the first feedback occasion <NUM> of the second COT <NUM> based on the one or more feedback configurations (e.g., determining the second COT <NUM> is an active COT), the HARQ feedback <NUM> of <FIG> indicating decoding of the first transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> in the feedback occasion <NUM> (first or second feedback occasion) of the second COT <NUM> based on the one or more feedback configurations (e.g., determining the second COT <NUM> is adjacent to the first COT <NUM>), the HARQ feedback <NUM> of <FIG> indicating decoding of the first transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> in the first feedback occasion <NUM> based on the one or more feedback configurations (e.g., determining a Type <NUM> channel access was successful prior to the first feedback occasion <NUM>), or the HARQ feedback <NUM> of <FIG> indicating decoding of the first transmission in slot n+<NUM> or slot n+<NUM> of the first COT <NUM> in the first feedback occasion <NUM> based on the one or more feedback configurations (e.g., determining the total number of feedback transmissions is less than a transmission number threshold or determining the total duration of feedback transmissions is less than a transmission duration threshold).

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

The above example method, wherein the determining the one or more feedback configurations comprises: determining the first feedback occasion is in a second COT that is active, wherein the feedback message is transmitted in the first feedback occasion of the second COT.

One or more of the above example methods, wherein the second COT is initiated by the receiving UE or a second UE.

One or more of the above example methods, further comprising: determining the feedback message can be transmitted in the second COT based on the second COT being shared with one or more second UEs, wherein the feedback message is transmitted further based on the second COT being shared.

One or more of the above example methods, further comprising: performing a channel access, wherein the feedback message is transmitted further based on the channel access being successful.

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

One or more of the above example methods, wherein the second COT is adjacent to the first COT based on the first COT and the second COT being initiated by a same UE including the receiving UE or a second UE.

One or more of the above example methods, wherein the second COT is adjacent to the first COT based on the first COT and the second COT being initiated by two UEs that are within a range threshold of each other, the two UEs including the receiving UE or one or more second UEs.

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

One or more of the above example methods, wherein the second COT is adjacent to the first COT based on a gap between the last slot of the first COT and a first slot of the second COT has a duration less than a gap threshold.

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

One or more of the above example methods, wherein the first feedback occasion is in a non-active COT.

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

One or more of the above example methods, wherein the first feedback occasion is determined based on a feedback periodicity and a global slot index or wherein the first feedback occasion is determined based on a feedback periodicity and a slot index within a second COT.

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

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

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

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

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

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

An example apparatus, comprising: means for performing one or more of the above second example methods.

For example, changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Also, various examples may omit, substitute, or add various procedures or components as appropriate.

It should be noted that the techniques described herein may be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" are often used interchangeably. IS-<NUM> Releases <NUM> and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-<NUM> (TIA-<NUM>) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, Flash-OFDM™, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP LTE and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over a shared radio frequency spectrum band. The description herein, however, describes an LTE/LTE-A system or <NUM> system for purposes of example, and LTE terminology is used in much of the description below, although the techniques may be applicable other next generation communication systems.

Other examples and implementations are within the scope of the disclosure.

For example, due to the nature of software, functions described above may be implemented using software executed by a specially programmed processor, hardware, firmware, hardwiring, or combinations of any of these.

A storage medium may be any available medium that may be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.

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