Patent Description:
<CIT> focuses on resource selection and interference management through sensing. <NPL> concentrates on power control adjustments and pathloss acquisition methods. <NPL> deals with radio link monitoring and failure detection using specific metrics and reference signals.

An apparatus and a method are provided as set out in the independent claims.

The transceiver may be used by a processor (e.g., controller/processor <NUM>) and memory <NUM> to perform aspects of any of the methods described herein (for example, as described with reference to <FIG>).

The transceiver may be used by a processor (e.g., controller/processor <NUM>) and memory <NUM> to perform aspects of any of the methods described herein (for example, as described with reference to <FIG>).

Controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform one or more techniques associated with effective contention windows (ECWs) for New Radio (NR) sidelink over unlicensed bands, as described in more detail elsewhere herein. For example, controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform or direct operations of, for example, process <NUM> of <FIG>, and/or other processes as described herein. Memories <NUM> and <NUM> may store data and program codes for base station <NUM> and UE <NUM>, respectively. In some aspects, memory <NUM> and/or memory <NUM> may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and/or program code) for wireless communication. For example, the one or more instructions, when executed (e.g., directly, or after compiling, converting, and/or interpreting) by one or more processors of the base station <NUM> and/or the UE <NUM>, may cause the one or more processors, the UE <NUM>, and/or the base station <NUM> to perform or direct operations of, for example, process <NUM> of <FIG>, and/or other processes as described herein. In some aspects, executing instructions may include running the instructions, converting the instructions, compiling the instructions, and/or interpreting the instructions, among other examples.

In some aspects, UE <NUM> may include means for selecting, for a sidelink transmission over an unlicensed band and associated with a medium access control (MAC) protocol data unit (PDU), one or more candidate resources of a set of candidate resources that are within an adaptive effective contention window (ECW), means for adjusting at least one parameter of the adaptive ECW to determine an adjusted at least one parameter based at least in part on a channel access output associated with the one or more candidate resources, means for transmitting the MAC PDU using the one or more candidate resources or an additional one or more candidate resources, wherein the additional one or more candidate resources are selected based at least in part on the adjusted at least one parameter, and/or the like. In some aspects, such means may include one or more components of UE <NUM> described in connection with <FIG>, such as controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, and/or the like.

<FIG> is a diagram illustrating an example <NUM> of sidelink communications, in accordance with the present disclosure.

As shown in <FIG>, a first UE <NUM>-<NUM> may communicate with a second UE <NUM>-<NUM> (and one or more other UEs <NUM>) via one or more sidelink channels <NUM>. The UEs <NUM>-<NUM> and <NUM>-<NUM> may communicate using the one or more sidelink channels <NUM> for P2P communications, D2D communications, V2X communications (e.g., which may include V2V communications, V2I communications, and/or V2P communications) and/or mesh networking. In some aspects, the UEs <NUM> (e.g., UE <NUM>-<NUM> and/or UE <NUM>-<NUM>) may correspond to one or more other UEs described elsewhere herein, such as UE <NUM>. In some aspects, the one or more sidelink channels <NUM> may use a PC5 interface and/or may operate in a high frequency band (e.g., the <NUM> band). Additionally, or alternatively, the UEs <NUM> may synchronize timing of transmission time intervals (TTIs) (e.g., frames, subframes, slots, or symbols) using global navigation satellite system (GNSS) timing.

As further shown in <FIG>, the one or more sidelink channels <NUM> may include a physical sidelink control channel (PSCCH) <NUM>, a physical sidelink shared channel (PSSCH) <NUM>, and/or a physical sidelink feedback channel (PSFCH) <NUM>. The PSCCH <NUM> may be used to communicate control information, similar to a physical downlink control channel (PDCCH) and/or a physical uplink control channel (PUCCH) used for cellular communications with a base station <NUM> via an access link or an access channel. The PSSCH <NUM> may be used to communicate data, similar to a physical downlink shared channel (PDSCH) and/or a physical uplink shared channel (PUSCH) used for cellular communications with a base station <NUM> via an access link or an access channel. For example, the PSCCH <NUM> may carry sidelink control information (SCI) <NUM>, which may indicate various control information used for sidelink communications, such as one or more resources (e.g., time resources, frequency resources, and/or spatial resources) where a transport block (TB) <NUM> may be carried on the PSSCH <NUM>. The TB <NUM> may include data. The PSFCH <NUM> may be used to communicate sidelink feedback <NUM>, such as hybrid automatic repeat request (HARQ) feedback (e.g., acknowledgement or negative acknowledgement (ACK/NACK) information), transmit power control (TPC), and/or a scheduling request (SR).

Although shown on the PSCCH <NUM>, in some aspects, the SCI <NUM> may include multiple communications in different stages, such as a first stage SCI (SCI-<NUM>) and a second stage SCI (SCI-<NUM>). The SCI-<NUM> may be transmitted on the PSCCH <NUM>. The SCI-<NUM> may be transmitted on the PSSCH <NUM>. The SCI-<NUM> may include, for example, an indication of one or more resources (e.g., time resources, frequency resources, and/or spatial resources) on the PSSCH <NUM>, information for decoding sidelink communications on the PSSCH, a quality of service (QoS) priority value, a resource reservation period, a PSSCH demodulation reference signal (DMRS) pattern, an SCI format for the SCI-<NUM>, a beta offset for the SCI-<NUM>, a quantity of PSSCH DMRS ports, and/or a modulation and coding scheme (MCS). The SCI-<NUM> may include information associated with data transmissions on the PSSCH <NUM>, such as a hybrid automatic repeat request (HARQ) process ID, a new data indicator (NDI), a source identifier, a destination identifier, and/or a channel state information (CSI) report trigger.

In some aspects, the one or more sidelink channels <NUM> may use resource pools. For example, a scheduling assignment (e.g., included in SCI <NUM>) may be transmitted in sub-channels using specific resource blocks (RBs) across time. In some aspects, data transmissions (e.g., on the PSSCH <NUM>) associated with a scheduling assignment may occupy adjacent RBs in the same subframe as the scheduling assignment (e.g., using frequency division multiplexing). In some aspects, a scheduling assignment and associated data transmissions are not transmitted on adjacent RBs.

In some aspects, a UE <NUM> may operate using a transmission mode where resource selection and/or scheduling is performed by the UE <NUM> (e.g., rather than a base station <NUM>). In some aspects, the UE <NUM> may perform resource selection and/or scheduling by sensing channel availability for transmissions. For example, the UE <NUM> may measure a received signal strength indicator (RSSI) parameter (e.g., a sidelink-RSSI (S-RSSI) parameter) associated with various sidelink channels, may measure a reference signal received power (RSRP) parameter (e.g., a PSSCH-RSRP parameter) associated with various sidelink channels, and/or may measure a reference signal received quality (RSRQ) parameter (e.g., a PSSCH-RSRQ parameter) associated with various sidelink channels, and may select a channel for transmission of a sidelink communication based at least in part on the measurement(s).

Additionally, or alternatively, the UE <NUM> may perform resource selection and/or scheduling using SCI <NUM> received in the PSCCH <NUM>, which may indicate occupied resources and/or channel parameters. Additionally, or alternatively, the UE <NUM> may perform resource selection and/or scheduling by determining a channel busy rate (CBR) associated with various sidelink channels, which may be used for rate control (e.g., by indicating a maximum number of resource blocks that the UE <NUM> can use for a particular set of subframes).

In the transmission mode where resource selection and/or scheduling is performed by a UE <NUM>, the UE <NUM> may generate sidelink grants, and may transmit the grants in SCI <NUM>. A sidelink grant may indicate, for example, one or more parameters (e.g., transmission parameters) to be used for an upcoming sidelink transmission, such as one or more resource blocks to be used for the upcoming sidelink transmission on the PSSCH <NUM> (e.g., for TBs <NUM>), one or more subframes to be used for the upcoming sidelink transmission, and/or an MCS to be used for the upcoming sidelink transmission. In some aspects, a UE <NUM> may generate a sidelink grant that indicates one or more parameters for semi-persistent scheduling (SPS), such as a periodicity of a sidelink transmission. Additionally, or alternatively, the UE <NUM> may generate a sidelink grant for event-driven scheduling, such as for an on-demand sidelink message.

<FIG> is a diagram illustrating an example <NUM> of sidelink communications and access link communications, in accordance with the present disclosure.

As shown in <FIG>, a transmitter (Tx)/receiver (Rx) UE <NUM> and an Rx/Tx UE <NUM> may communicate with one another via a sidelink, as described above in connection with <FIG>. As further shown, in some sidelink modes, a base station <NUM> may communicate with the Tx/Rx UE <NUM> via a first access link. Additionally, or alternatively, in some sidelink modes, the base station <NUM> may communicate with the Rx/Tx UE <NUM> via a second access link. The Tx/Rx UE <NUM> and/or the Rx/Tx UE <NUM> may correspond to one or more UEs described elsewhere herein, such as the UE <NUM> of <FIG>. Thus, a direct link between UEs <NUM> (e.g., via a PC5 interface) may be referred to as a sidelink, and a direct link between a base station <NUM> and a UE <NUM> (e.g., via a Uu interface) may be referred to as an access link. Sidelink communications may be transmitted via the sidelink, and access link communications may be transmitted via the access link. An access link communication may be either a downlink communication (from a base station <NUM> to a UE <NUM>) or an uplink communication (from a UE <NUM> to a base station <NUM>).

<FIG> is a diagram illustrating an example <NUM> of resource selection for sidelink, in accordance with the present disclosure. The example <NUM> shows a scheme for sensing a sidelink channel, based on a resource selection window, for selecting resources for a sidelink communication.

As shown in <FIG>, a UE may perform a sensing procedure in a sensing window. In some cases, the sensing window may be <NUM> milliseconds (ms) (e.g., for aperiodic resource reservation, such as aperiodic reservation in one or more slots of up to <NUM> logical slots in the future) or <NUM> (e.g., for periodic resource reservation). In some cases, a UE configured for communication in an NR network may use a sensing procedure for aperiodic or periodic resource reservation.

According to the sensing procedure, the UE may decode control messages relating to resource reservations of other UEs, as well as perform measurements (e.g., RSRP measurements) associated with one or more sidelink channels. For example, UEs may transmit reservation information (e.g., in SCI) that indicates a resource reservation for a current slot (e.g., the slot in which the reservation information is transmitted) and for one or more (e.g., up to two) future slots. A resource allocation associated with a resource reservation may be one or more sub-channels in a frequency domain and one slot in a time domain. In some cases, a resource reservation may be aperiodic or periodic. In periodic resource reservation, a UE may signal (e.g., in the reservation information in SCI) a period for the resource reservation (e.g., a value between <NUM> and <NUM>). In some cases, the sensing procedure may be performed by a physical layer of the UE based on a request from a medium access control (MAC) layer of the UE.

As shown in <FIG>, the UE may determine to select resources for a sidelink communication based at least in part on a resource selection trigger. For example, resource selection may be triggered when the UE has a packet that is to be transmitted. Based at least in part on the resource selection trigger, the UE may determine one or more resources that are available for selection in a resource selection window (RSW). That is, the UE may determine the one or more available resources based at least in part on the sensing procedure performed by the UE. For example, the sensing procedure may provide an indication of candidate resources in the RSW that are occupied and/or resources in the RSW associated with high interference.

The physical layer of the UE can report the set of candidate resources to the MAC layer of the UE. The MAC layer randomly chooses for transmission one or more resources of the set of candidate resources reported. In some cases, the UE may be reserving resources for a hybrid automatic request response (HARQ) transmission and/or retransmission, and the resources for multiple physical sidelink shared channels (PSSCHs) for the same transmission block may be randomly selected by the MAC layer.

The RSW shown in <FIG> may be defined by a first time period, T1, and a second time period, T2. In some cases, if a resource selection trigger occurs in a subframe n, the resource selection window is from n + T<NUM> to n + T<NUM>. In this case, T<NUM> may be less than a processing time (Tproc,<NUM>). Moreover, T<NUM> may be greater than or equal to T<NUM>,min, which may be a value configured for the UE based at least in part on a priority of the UE, and less than or equal to <NUM> or a remaining packet delay budget (PDB) of the UE (e.g., T<NUM> may be less than or equal to a remaining PDB).

A PDB is a constraint dictating a maximum delay between a time of packet arrival and a time of a last transmission of the packet. For example, each packet that arrives at a transmitter of a UE for transmission by the transmitter is associated with a PDB and a quantity of transmissions (a quantity of times that the packet is to be transmitted). The PDB and the quantity of transmissions may vary among packets depending on, for example, an application or a service associated with the packet (e.g., in order to achieve a desired coverage, range, reliability, and/or the like).

Some aspects described herein related to an unlicensed radio frequency spectrum band, which may be used for communications in a wireless network, such as wireless network <NUM>. In some aspects, the unlicensed radio frequency spectrum band may be used by base stations <NUM> and UEs <NUM> of a cellular network for cellular communications (e.g., NR communications), and by Wi-Fi access points and Wi-Fi stations of a Wi-Fi network for Wi-Fi communications. The unlicensed radio frequency spectrum band may be used in the cellular network in combination with, or independent from, a licensed radio frequency spectrum band. In some examples, the unlicensed radio frequency spectrum band may be a radio frequency spectrum band for which a device may need to contend for access because the radio frequency spectrum band is available, at least in part, for unlicensed use, such as Wi-Fi use.

Prior to gaining access to, and communicating over, an unlicensed radio frequency spectrum band, a UE may perform a listen-before-talk (LBT) procedure to contend for access to the unlicensed radio frequency spectrum band. An LBT procedure may include determining a channel busy ratio (CBR) to determine whether a channel of the unlicensed radio frequency spectrum band is available. The UE may use a pre-configured mapping from CBR to channel usage ratio (CR) to self-regulate channel access attempts, to avoid heavy congestion and contention in a system. The UE may perform fewer channel access attempts when the estimated CBR value is high.

In some cases, the presence of interference associated with the NR RAT from one or more other RATs can result in erroneous CBR estimates. For example, a sub-channel can be detected as "busy" in a CBR estimate when it is in fact occupied by one or more other RATs. Consequently, a typical case of a CBR based congestion control may break down. If a UE reacts to erroneous CBR, the UE can be starved by the other RAT or RATs. In addition, the robustness of CBR based congestion control can be frequently challenged due to a strong inter sub-channel leakage that can occur, especially for low-complexity receiver implementations. In some environments, a UE may be starved of access to a channel of an unlicensed radio frequency spectrum band due to activity of another RAT, such as Wi-Fi.

In some cases, with regard to some RATs, a UE adopts load-based equipment (LBE) channel access, of which the main channel access engine has a contention management scheme designed to manage channel access. In LBE, after observing one or more lost packets as a possible symptom of congestion, an LBE code can double its contention window (CW) to cool down channel access contention. However, as a node in a synchronous system, a UE cannot fully operate like an LBE node, and a UE cannot solely rely on LBE CW control for contention/congestion management.

In some cases, the RSW can be understood as a preliminary contention window (CW) for an NR sidelink autonomous sensing procedure. In some cases, the physical layer may filter the candidate resources to report only available resources to the MAC level. A slot index randomly selected by the MAC layer from the filtered RSW can be understood as a random number for a listen-before-talk (LBT) counter. In general, the smaller the slot indices selected by UEs near one another, the shorter the latency in channel access. However, smaller slot indices may increase risk of collision and/or congestion. There is currently no adaptive management for collision and/or congestion associated with the preliminary CW in NR sidelink, because collision and/or congestion is managed using the CBR mechanism described above. However, as described above, the CBR mechanism may not work well in unlicensed bands.

According to some aspects of techniques and apparatuses described herein, a UE may be configured with effective contention windows (ECWs) for NR sidelink over unlicensed band. The ECWs may serve as an effective CW based congestion/contention control mechanism for a sensing procedure for resource selection. In some aspects, techniques and apparatuses described herein may include selecting one or more candidate resources of a set of candidate resources that are within an adaptive ECW. A channel access attempt may be performed and the UE may adjust at least one parameter of the adaptive ECW to determine an adjusted at least one parameter of the adaptive ECW. The UE may adjust the at least one parameter based at least in part on a channel access output associated with the one or more candidate resources. The UE may transmit a MAC PDU using the one or more candidate resources or an additional one or more candidate resources. The additional one or more candidate resources may be selected based at least in part on the adjusted at least one parameter.

In some aspects, the adaptive ECW may be configured to facilitate resource selection in the autonomous sensing procedure of NR sidelink Mode <NUM> when operating in the unlicensed band. Aspects may enable adaptive ECW management according to channel access output at the chosen sidelink resource. For example, the UE may increase the adaptive ECW for a channel access failure, and may decrease the adaptive ECW when channel access is successful. In this way, aspects may provide an adaptive resource selection scheme that can enable adjustment to an ECW responsive to channel access outputs. As a result, aspects of the techniques and apparatuses described herein may increase channel access reliability in sidelink over unlicensed bands, increase efficiency of sidelink communications over unlicensed bands, and reduce collisions of sidelink communications over unlicensed bands.

<FIG> is a diagram illustrating an example <NUM> associated with ECWs for NR sidelink over unlicensed bands, in accordance with the present disclosure. As shown in <FIG>, a UE <NUM> and a UE <NUM> may communicate with one another via a sidelink. The UE <NUM> and/or the UE <NUM> may be, be similar to, include, or be included in the UE <NUM> shown in <FIG>.

As show by reference number <NUM>, the UE <NUM> may select one or more candidate resources of a set of candidate resources that are within an adaptive ECW. The UE <NUM> may select the one or more candidate resources for a sidelink transmission over an unlicensed band. The sidelink transmission may be associated with a MAC protocol data unit (PDU). The UE <NUM> may select the one or more candidate resources randomly from the set of candidate resources that are within the adaptive ECW.

The UE <NUM> may use a physical layer to determine the set of candidate resources and a MAC layer to select the one or more candidate resources from the set. The physical layer of the UE <NUM> may determine the set of candidate resources based at least in part on a sensing operation performed by a physical layer. As shown in <FIG> and described below in connection with <FIG>, the set of candidate resources may include an effective available resource set. The effective available resource set may include a subset of a plurality of identified resources within a resource selection window that are available.

As show by reference number <NUM>, the UE <NUM> may adjust at least one parameter of the adaptive ECW to determine an adjusted at least one parameter. The UE <NUM> may adjust the at least one parameter based at least in part on a channel access output associated with the one or more candidate resources. The channel access output may include an indication of a channel access failure. For example, the UE <NUM> may use the selected one or more candidate resources to attempt to access a corresponding channel. If the UE <NUM> fails to access the channel, the UE <NUM> may adjust the adaptive ECW and select an additional set of candidate resources that are within the adjusted adaptive ECW. The indication of the channel access failure may include a failure to receive an acknowledgement (ACK) feedback message associated with an ACK-based PSSCH transmission, a failure of an LBT procedure associated with a slot boundary, a failure to achieve a specified channel occupancy time at a specified sidelink slot, and/or the like.

The at least one parameter of the adaptive ECW that is adjusted may include an anchor time, an adaptive ECW offset associated with the anchor time, an adaptive ECW width, and/or the like. The adaptive ECW offset may include a number of symbols between the anchor time and an initial symbol corresponding to the adaptive ECW. The adaptive ECW width may include a number of symbols.

As shown by reference number <NUM> and as indicated above, the UE <NUM> may adjust the adaptive ECW offset, s, associated with an anchor time. The UE <NUM> may adjust the adaptive ECW offset s linearly (e.g., by adding an adjustment factor to the adaptive ECW offset, by adjusting the adaptive ECW offset using a linear equation, and/or the like), multiplicatively (e.g., by multiplying the adaptive ECW offset by an adjustment factor, by adjusting the adaptive ECW offset using a non-linear equation, and/or the like), and/or the like. The UE <NUM> may establish a fixed adaptive ECW width, w, and adjust a dynamic adaptive ECW offset s. The channel access output may include an indication of a channel access failure, and the UE <NUM> may increase the adaptive ECW offset s based at least in part on the indication of the channel access failure. The channel access output may include an indication of a channel access success, and the UE <NUM> may decrease the adaptive ECW offset based at least in part on the indication of the channel access success.

The UE <NUM> may introduce randomness in addition to the randomness introduce by random selection from the set of candidate resources. For example, the UE <NUM> may set an upper distribution bound based at least in part on the channel access output. The upper distribution bound may be determined based on an initial adaptive ECW offset value of the adaptive ECW offset s. The UE <NUM> may set the upper distribution bound to equal the initial adaptive ECW offset value of the adaptive ECW offset s. The UE <NUM> may select a random number, S, from a uniform distribution between zero and the upper distribution bound and adjust, based at least in part on the random number, the adaptive ECW offset to determine an adjusted adaptive ECW offset value. For example, the UE <NUM> may shift the beginning of the ECW, the middle of the ECW, the end of the ECW, or the like, to align with the selected random number S.

As shown by reference number <NUM> and as indicated above, the UE <NUM> may adjust the adaptive ECW width w. The UE <NUM> may adjust the offset s linearly, multiplicatively, and/or the like. The UE <NUM> may establish a fixed adaptive ECW offset s and adjust the adaptive ECW width w. The channel access output may include an indication of a channel access failure, and the UE <NUM> may increase the adaptive ECW width w, based at least in part on the indication of the channel access failure. The channel access output may include an indication of a channel access success, and the UE <NUM> may decrease the adaptive ECW width w, based at least in part on the indication of the channel access success.

In some aspects, the UE <NUM> may adjust the adaptive ECW offset s and the adaptive ECW width w. The channel access output may include an indication of a channel access failure, and the UE <NUM> may increase, based at least in part on the indication of the channel access failure, the adaptive ECW offset s and the adaptive ECW width w. The channel access output may include an indication of a channel access success, and the UE <NUM> may decrease, based at least in part on the indication of the channel access success, the adaptive ECW offset s and the adaptive ECW width w.

As indicated above, the at least one parameter of the adaptive ECW may include an anchor time. The anchor time may be defined by the MAC layer of the UE to include a first slot index of a resource selection window associated with the set of candidate resources, a slot index corresponding to a first available resource within the RSW, a slot index corresponding to a projected LBT completion time associated with the MAC PDU, a maximum slot index of any combination thereof, and/or the like.

The UE <NUM> may determine the projected LBT completion time based at least in part on a channel access priority class (CAPC) of the MAC PDU. The UE <NUM> may request, from a physical layer and using the MAC layer, a contention window size corresponding to the CAPC of the MAC PDU. The UE <NUM> may determine the projected LBT completion time using the MAC layer and based at least in part on the contention window size. The UE <NUM> may request, from the physical layer and using the MAC layer, an LBT counter value corresponding to the CAPC of the MAC PDU. The UE <NUM> may determine the projected LBT completion time using the MAC layer and based at least in part on the LBT counter value.

The UE <NUM> may adjust the at least one parameter using a binary exponential back-off (BEB) algorithm to determine an adjusted value of the at least one parameter. The UE <NUM> may use the BEB algorithm by determining a minimum parameter value of the at least one parameter and a maximum parameter value of the at least one parameter. The UE <NUM> may set the at least one parameter to the minimum parameter value. The UE <NUM> may set, for an iteration, the at least one parameter to a minimum of the maximum parameter value and two times a value of the at least one parameter corresponding to a preceding iteration, based at least in part on the channel access output comprising an indication of a channel access failure. Otherwise, the UE <NUM> may set the at least one parameter to a minimum parameter value based at least in part on the channel access output comprising an indication of a channel access success.

The UE <NUM> may adjust the at least one parameter by setting the at least one parameter to the maximum parameter value for a number of iterations. The UE <NUM> may determine that the number of iterations satisfies an iteration threshold, and set the at least one parameter to the minimum parameter value based at least in part on determining that the number of iterations satisfies the iteration threshold.

The UE <NUM> may adjust the at least one parameter by determining a minimum parameter value of the at least one parameter and a maximum parameter value of the at least one parameter and determining an increase step size and a decrease step size. The UE <NUM> may set, for an iteration, the at least one parameter to a minimum of the maximum parameter value and a sum of a value of the at least one parameter corresponding to a preceding iteration and the increase step size, based at least in part on the channel access output comprising an indication of a channel access failure. The UE <NUM> may set the at least one parameter to a maximum of the minimum parameter value and a difference of a value of the at least one parameter corresponding to the preceding iteration and the decrease step size, based at least in part on the channel access output comprising an indication of a channel access success. The increase step size and/or the decrease step size may correspond to a collision rate based at least in part on a block error rate determined in a channel quality information outer-loop rate control procedure.

The UE <NUM> may adjust the at least one parameter based at least in part on determining that an LBT CW parameter comprises a maximum LBT CW value. The UE <NUM> may adjust the at least one parameter by increasing a value of the at least one parameter and setting an LBT contention window (CW) value to a minimum LBT CW value based at least in part on increasing the value of the at least one parameter. The UE <NUM> may determine that the channel access output includes an indication of a channel access failure, and determine that a slot comprises one or more sidelink control information (SCI) transmissions having a signal strength that satisfies a signal strength threshold. The UE <NUM> may increase a value of the at least one parameter corresponding to the slot based at least in part on determining that the slot comprises the one or more SCI transmissions having a signal strength that satisfies a signal strength threshold. The UE <NUM> may determine that a size of an LBT CW is greater than a size of the slot, and increase the value of the at least one parameter corresponding to the slot based at least in part on determining that the size of the LBT CW is greater than the size of the slot.

In some aspects, the UE <NUM> may transmit and re-transmit HARQ transmissions and may adjust an adaptive ECW parameter based at least in part on a channel access output associated with requesting resources for transmitting the HARQ transmission. The UE <NUM> may select one or more resources for one or more HARQ transmissions based at least in part on the adaptive ECW. The UE <NUM> may select the one or more resources for the one or more HARQ transmissions by selecting a first resource for an initial HARQ transmission from the set of candidate resources that are within the adaptive ECW, and determining an anchor time associated with a HARQ retransmission of the initial HARQ transmission based at least in part on a slot index corresponding to the initial resource and a projected LBT completion interval. The UE <NUM> may determine a repositioned adaptive ECW with respect to the anchor time associated with the initial HARQ transmission. The UE <NUM> may select a second resource for the HARQ retransmission from an additional set of candidate resources that are within the repositioned adaptive ECW.

The UE <NUM> may determine the repositioned adaptive ECW based at least in part on at least one PDB. The at least one PDB may include a first PDB associated with the initial HARQ transmission, where the first PDB has a first PDB value, and a second PDB associated with the HARQ retransmission, where the second PDB has a second PDB value that is lower than the first PDB value.

The UE <NUM> may adjust the at least one parameter of the adaptive ECW based at least in part on a CBR. The UE <NUM> may receive a configuration that indicates a mapping associated with the CBR. The UE <NUM> may adjust the at least one parameter of the adaptive ECW based at least in part on the mapping. The configuration may be carried in a system information block (SIB) or a radio resource control (RRC) message. The mapping may include a mapping from the CBR to an activation or deactivation of the adaptive ECW, a mapping from the CBR to the at least one parameter of the adaptive ECW, a mapping from the CBR to a minimum parameter value of the at least one parameter of the adaptive ECW, a mapping from the CBR to a maximum parameter value of the at least one parameter of the adaptive ECW, a binary exponential back-off associated with the at least one parameter of the adaptive ECW, or a collision rate associated with the at least one parameter of the adaptive ECW.

The UE <NUM> may determine that a first traffic priority of a plurality of traffic priorities corresponds to the MAC PDU. The UE <NUM> may select the one or more candidate resources of the set of candidate resources that are within the adaptive ECW based at least in part on determining that the first traffic priority of the plurality of traffic priorities corresponds to the MAC PDU. The adaptive ECW may be associated with the first traffic priority, and an additional adaptive ECW may be associated with a second traffic priority of the plurality of traffic priorities. The adaptive ECW may be associated with a first bandwidth of a plurality of bandwidths corresponding to the set of candidate resources. An additional adaptive ECW may be associated with a second bandwidth of the plurality of bandwidths.

The UE <NUM> may send, using a MAC layer of the UE, a sidelink sensing request to a physical layer of the UE, where the sidelink sensing request indicates, based at least in part on the adaptive ECW, an RSW. The sidelink sensing request indicates a first time period and a second time period, where the first time period comprises an offset between a resource selection trigger and the RSW, and the second time period comprises a width of the RSW. The second time period may include an extra packet data budget associated with the MAC PDU. The sidelink sensing request may indicate the RSW based at least in part on an additional adaptive ECW. In some aspects, the UE <NUM> may adjust, according to an adaptive ECW, an RSW and/or a sensing window. For example, the UE <NUM> may enlarge a sensing window, based at least in part on the adaptive ECW, to avoid a resource collision such as a time domain resource collision and/or a frequency domain resource collision.

The adaptive ECW may be associated with an initial HARQ transmission, and the additional adaptive ECW may be associated with a retransmission of the initial HARQ transmission. The sidelink sensing request indicates an additional RSW based at least in part on an additional adaptive ECW. The adaptive ECW is associated with an initial hybrid automatic repeat request (HARQ) transmission, and the additional adaptive ECW may be associated with a retransmission of the initial HARQ transmission. The adaptive ECW may be associated with an initial HARQ transmission. The UE <NUM> may, using the MAC layer of the UE, send an additional sidelink sensing request to the physical layer of the UE. The additional sidelink sensing request may indicate, based at least in part on an additional adaptive ECW, an additional RSW. The additional adaptive ECW may be associated with a retransmission of the initial HARQ transmission.

As show by reference number <NUM>, the UE <NUM> may transmit a MAC PDU using the one or more candidate resources or an additional one or more candidate resources. The additional one or more candidate resources may be selected based at least in part on the adjusted at least one parameter.

<FIG> is a diagram illustrating an example <NUM> associated with ECWs for NR sidelink over unlicensed bands, in accordance with the present disclosure. The example <NUM> shows a plurality of identified resources that have been determined by a physical layer of a UE (e.g., the UE <NUM> shown in <FIG>, the UE <NUM> shown in <FIG>, and/or the like).

As shown, the UE (e.g., a MAC layer of the UE) may apply an adaptive ECW to the plurality of identified resources within an RSW to determine a set of candidate resources that are within the adaptive ECW. The adaptive ECW may be defined by an adaptive ECW offset, s (shown as s = <NUM>) and an adaptive ECW width, w, of orthogonal frequency division multiplexing (OFDM) symbols (shown as w = <NUM>). The UE (e.g., the MAC layer of the UE) may randomly select one or more resources from the set of candidate resources that are within the adaptive ECW. In the illustrated example, the UE <NUM> may select from among the resources indexed as {<NUM>, <NUM>, <NUM>}.

As shown by reference number <NUM>, the UE (e.g., using the MAC layer) may select the one or more candidate resources from among an effective available resource set. The effective available resource set may include a subset of the plurality of identified resources within a resource selection window. As shown, the UE (e.g., using the MAC layer) may determine the effective available resource set by excluding one or more slots of the plurality of identified resources that do not include one or more available resources. Thus, in the illustrated example, the UE may exclude the fourth slot, which contains no available resources. As a result, the effective available resource set includes the resources associated with the first, second, third, and fifth slots. The UE may apply the adaptive ECW to this effective available resource set. As a result, additional efficiencies in processing during resource selection may be enabled by aspects of the techniques described herein.

<FIG> is a diagram illustrating an example <NUM> associated with ECWs for NR sidelink over unlicensed bands, in accordance with the present disclosure. The example <NUM> shows a procedure for resource selection for HARQ transmission and retransmission base at least in part on the adaptive ECW. As shown, a UE (e.g., the UE <NUM> shown in <FIG>, the UE <NUM> shown in <FIG>, and/or the like) may select one or more resources for one or more HARQ transmissions based at least in part on the adaptive ECW. The UE may select the one or more resources by selecting a first resource for an initial HARQ transmission from the set of candidate resources that are within the adaptive ECW. The candidate resources may include effective available resources (as shown and as described above in connection with <FIG>). The UE may determine an anchor time associated with a HARQ retransmission of the initial HARQ transmission based at least in part on a slot index corresponding to the initial resource and a projected LBT completion interval.

The UE may also determine a repositioned adaptive ECW with respect to the anchor time associated with the initial HARQ transmission, as shown, selecting a second resource for the HARQ retransmission from an additional set of candidate resources that are within the repositioned adaptive ECW. The UE may determine the repositioned adaptive ECW based at least in part on at least one PDB. The at least one PDB may include a first PDB associated with the initial HARQ transmission, where the first PDB has a first PDB value, and a second PDB associated with the HARQ retransmission, where the second PDB has a second PDB value that is lower than the first PDB value. The at least one parameter of the adaptive ECW may include at least one first parameter value, and at least one additional parameter of the repositioned adaptive ECW may include at least one second parameter value that is less than the at least one first parameter value.

The UE may adjust the at least one parameter of the adaptive ECW based at least in part on a CBR. The UE may receive (e.g., from a base station, such as base station <NUM> shown in <FIG>) a configuration that indicates a mapping associated with the CBR. The configuration may be carried in a SIB, an RRC message, and/or the like. The UE may adjust the at least one parameter of the adaptive ECW based at least in part on the mapping. The mapping may include a mapping from the CBR to an activation or deactivation of the adaptive ECW, a mapping from the CBR to the at least one parameter of the adaptive ECW, a mapping from the CBR to a minimum parameter value of the at least one parameter of the adaptive ECW, a mapping from the CBR to a maximum parameter value of the at least one parameter of the adaptive ECW, a binary exponential back-off associated with the at least one parameter of the adaptive ECW, a collision rate associated with the at least one parameter of the adaptive ECW, and/or the like.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with the present disclosure. Example process <NUM> is an example where the UE (e.g., UE <NUM>) performs operations associated with ECWs for NR sidelink over unlicensed bands.

As shown in <FIG>, in some aspects, process <NUM> may include selecting, for a sidelink transmission over an unlicensed band and associated with a MAC PDU, one or more candidate resources of a set of candidate resources that are within an adaptive ECW (block <NUM>). For example, the UE (e.g., using communication manager <NUM>, depicted in <FIG>) may select, for a sidelink transmission over an unlicensed band and associated with a MAC PDU, one or more candidate resources of a set of candidate resources that are within an adaptive ECW, as described above.

As further shown in <FIG>, in some aspects, process <NUM> may include adjusting at least one parameter of the adaptive ECW to determine an adjusted at least one parameter based at least in part on a channel access output associated with the one or more candidate resources (block <NUM>). For example, the UE (e.g., using communication manager <NUM>, depicted in <FIG>) may adjust at least one parameter of the adaptive ECW to determine an adjusted at least one parameter based at least in part on a channel access output associated with the one or more candidate resources, as described above.

As further shown in <FIG>, in some aspects, process <NUM> may include transmitting the MAC PDU using the one or more candidate resources or an additional one or more candidate resources, wherein the additional one or more candidate resources are selected based at least in part on the adjusted at least one parameter (block <NUM>). For example, the UE (e.g., using transmission component <NUM>, depicted in <FIG>) may transmit the MAC PDU using the one or more candidate resources or an additional one or more candidate resources, wherein the additional one or more candidate resources are selected based at least in part on the adjusted at least one parameter, as described above.

In a first aspect, selecting the one or more candidate resources comprises selecting the one or more candidate resources randomly.

In a second aspect, alone or in combination with the first aspect, the at least one parameter of the adaptive ECW comprises at least one of an anchor time, an adaptive ECW offset associated with the anchor time, or an adaptive ECW width.

In a third aspect, alone or in combination with one or more of the first and second aspects, the adaptive ECW offset comprises a number of symbols between the anchor time and an initial symbol corresponding to the adaptive ECW.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the adaptive ECW width comprises a number of symbols.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the channel access output comprises an indication of a channel access failure, and adjusting the at least one parameter comprises increasing the adaptive ECW width based at least in part on the indication of the channel access failure.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, increasing the adaptive ECW width comprises increasing the adaptive ECW width multiplicatively.

In a seventh aspect, alone or in combination with one or more of the first through fourth aspects, the channel access output comprises an indication of a channel access success, and adjusting the at least one parameter comprises decreasing the adaptive ECW width based at least in part on the indication of the channel access success.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, decreasing the adaptive ECW width comprises decreasing the adaptive ECW width linearly.

In a ninth aspect, alone or in combination with one or more of the first through fourth aspects, the channel access output comprises an indication of a channel access failure, and adjusting the at least one parameter comprises increasing the adaptive ECW offset based at least in part on the indication of the channel access failure.

In a tenth aspect, alone or in combination with one or more of the first through fourth aspects, the channel access output comprises an indication of a channel access success, and adjusting the at least one parameter comprises decreasing the adaptive ECW offset based at least in part on the indication of the channel access success.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, adjusting the at least one parameter comprises setting an upper distribution bound based at least in part on the channel access output, wherein the upper distribution bound is determined based on an initial adaptive ECW offset value of the adaptive ECW offset, selecting a random number from a uniform distribution between zero and the upper distribution bound, and adjusting, based at least in part on the random number, the adaptive ECW offset to determine an adjusted adaptive ECW offset value.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the adjusted adaptive ECW offset value corresponds to a number of symbols offset from the anchor time, wherein the number of symbols comprises the random number.

In a thirteenth aspect, alone or in combination with one or more of the first through fourth aspects, the channel access output comprises an indication of a channel access failure, and adjusting the at least one parameter comprises increasing, based at least in part on the indication of the channel access failure, the adaptive ECW width and the adaptive ECW offset.

In a fourteenth aspect, alone or in combination with one or more of the first through fourth aspects, the channel access output comprises an indication of a channel access success, and adjusting the at least one parameter comprises decreasing, based at least in part on the indication of the channel access success, the adaptive ECW width and the adaptive ECW offset.

In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, the channel access output comprises an indication of a channel access failure, and the indication of the channel access failure comprises at least one of a failure to receive an ACK feedback message associated with an ACK-based physical sidelink shared channel transmission, a failure of an LBT procedure associated with a slot boundary, or a failure to achieve a specified channel occupancy time at a specified sidelink slot.

In a sixteenth aspect, alone or in combination with one or more of the first through fifteenth aspects, process <NUM> includes determining the set of candidate resources based at least in part on a sensing operation performed by a physical layer of the UE.

In a seventeenth aspect, alone or in combination with one or more of the first through sixteenth aspects, the set of candidate resources comprises an effective available resource set, wherein the effective available resource set comprises a subset of a plurality of identified resources within a resource selection window.

In an eighteenth aspect, alone or in combination with one or more of the first through seventeenth aspects, process <NUM> includes determining the effective available resource set by excluding one or more slots of the plurality of identified resources that do not include one or more available resources.

In a nineteenth aspect, alone or in combination with one or more of the first through eighteenth aspects, the at least one parameter of the adaptive ECW comprises an anchor time, and process <NUM> further comprises defining, using a MAC layer, the anchor time to include a first slot index of a resource selection window associated with the set of candidate resources, a slot index corresponding to a first available resource within the resource selection window, a slot index corresponding to a projected LBT completion time associated with the MAC PDU, or a maximum slot index of any combination thereof.

In a twentieth aspect, alone or in combination with one or more of the first through nineteenth aspects, process <NUM> includes determining the projected LBT completion time based at least in part on a CAPC of the MAC PDU.

In a twenty-first aspect, alone or in combination with one or more of the first through twentieth aspects, process <NUM> includes requesting, from a physical layer and using the MAC layer, a contention window size corresponding to the CAPC of the MAC PDU, wherein determining the projected LBT completion time comprises determining the projected LBT completion time using the MAC layer and based at least in part on the contention window size.

In a twenty-second aspect, alone or in combination with one or more of the first through twenty-first aspects, process <NUM> includes requesting, from a physical layer and using the MAC layer, an LBT counter value corresponding to the CAPC of the MAC PDU, wherein determining the projected LBT completion time comprises determining the projected LBT completion time using the MAC layer and based at least in part on the LBT counter value.

In a twenty-third aspect, alone or in combination with one or more of the first through twenty-second aspects, adjusting the at least one parameter comprises using a binary exponential back-off algorithm to determine an adjusted value of the at least one parameter.

In a twenty-fourth aspect, alone or in combination with one or more of the first through twenty-third aspects, using the binary exponential back-off algorithm comprises determining a minimum parameter value of the at least one parameter and a maximum parameter value of the at least one parameter, setting the at least one parameter to the minimum parameter value, and setting, for an iteration, the at least one parameter to a minimum of the maximum parameter value and two times a value of the at least one parameter corresponding to a preceding iteration, based at least in part on the channel access output comprising an indication of a channel access failure, or the minimum parameter value based at least in part on the channel access output comprising an indication of a channel access success.

In a twenty-fifth aspect, alone or in combination with one or more of the first through twenty-fourth aspects, adjusting the at least one parameter comprises setting the at least one parameter to the maximum parameter value for a number of iterations, determining that the number of iterations satisfies an iteration threshold, and setting the at least one parameter to the minimum parameter value based at least in part on determining that the number of iterations satisfies the iteration threshold.

In a twenty-sixth aspect, alone or in combination with one or more of the first through twenty-fifth aspects, adjusting the at least one parameter comprises determining a minimum parameter value of the at least one parameter and a maximum parameter value of the at least one parameter, determining an increase step size and a decrease step size, and setting, for an iteration, the at least one parameter to a minimum of the maximum parameter value and a sum of a value of the at least one parameter corresponding to a preceding iteration and the increase step size, based at least in part on the channel access output comprising an indication of a channel access failure, or a maximum of the minimum parameter value and a difference of a value of the at least one parameter corresponding to the preceding iteration and the decrease step size, based at least in part on the channel access output comprising an indication of a channel access success.

In a twenty-seventh aspect, alone or in combination with one or more of the first through twenty-sixth aspects, at least one of the increase step size or the decrease step size corresponds to a collision rate based at least in part on a block error rate determined in a channel quality information outer-loop rate control procedure.

In a twenty-eighth aspect, alone or in combination with one or more of the first through twenty-seventh aspects, adjusting the at least one parameter comprises adjusting the at least one parameter based at least in part on determining that an LBT CW parameter comprises a maximum LBT CW value.

In a twenty-ninth aspect, alone or in combination with one or more of the first through twenty-eighth aspects, adjusting the at least one parameter comprises increasing a value of the at least one parameter, and process <NUM> further comprises setting an LBT CW value to a minimum LBT CW value based at least in part on increasing the value of the at least one parameter.

In a thirtieth aspect, alone or in combination with one or more of the first through twenty-ninth aspects, adjusting the at least one parameter comprises determining that the channel access output comprises an indication of a channel access failure, determining that a slot comprises one or more SCI transmissions having a signal strength that satisfies a signal strength threshold, and increasing a value of the at least one parameter corresponding to the slot based at least in part on determining that the slot comprises the one or more SCI transmissions having a signal strength that satisfies a signal strength threshold.

In a thirty-first aspect, alone or in combination with one or more of the first through thirtieth aspects, process <NUM> includes determining that a size of an LBT CW is greater than a size of the slot, and increasing the value of the at least one parameter corresponding to the slot comprises increasing the value of the at least one parameter corresponding to the slot based at least in part on determining that the size of the LBT CW is greater than the size of the slot.

In a thirty-second aspect, alone or in combination with one or more of the first through thirty-first aspects, process <NUM> includes selecting one or more resources for one or more HARQ transmissions based at least in part on the adaptive ECW.

In a thirty-third aspect, alone or in combination with one or more of the first through thirty-second aspects, selecting the one or more resources for the one or more HARQ transmissions comprises selecting a first resource for an initial HARQ transmission from the set of candidate resources that are within the adaptive ECW, determining an anchor time associated with a HARQ retransmission of the initial HARQ transmission based at least in part on a slot index corresponding to the initial resource and a projected listen-before-talk completion interval, determining a repositioned adaptive ECW with respect to the anchor time associated with the initial HARQ transmission, and selecting a second resource for the HARQ retransmission from an additional set of candidate resources that are within the repositioned adaptive ECW.

In a thirty-fourth aspect, alone or in combination with one or more of the first through thirty-third aspects, determining the repositioned adaptive ECW comprises determining the repositioned adaptive ECW based at least in part on at least one PDB.

In a thirty-fifth aspect, alone or in combination with one or more of the first through thirty-fourth aspects, the at least one PDB comprises a first PDB associated with the initial HARQ transmission, wherein the first PDB has a first PDB value, and a second PDB associated with the HARQ retransmission, wherein the second PDB has a second PDB value that is lower than the first PDB value.

In a thirty-sixth aspect, alone or in combination with one or more of the first through thirty-fifth aspects, the at least one parameter of the adaptive ECW has at least one first parameter value, and at least one additional parameter of the repositioned adaptive ECW has at least one second parameter value that is less than the at least one first parameter value.

In a thirty-seventh aspect, alone or in combination with one or more of the first through thirty-sixth aspects, adjusting the at least one parameter of the adaptive ECW comprises adjusting the at least one parameter of the adaptive ECW based at least in part on a CBR.

In a thirty-eighth aspect, alone or in combination with one or more of the first through thirty-seventh aspects, process <NUM> includes receiving a configuration that indicates a mapping associated with the CBR, wherein adjusting the at least one parameter of the adaptive ECW comprises adjusting the at least one parameter of the adaptive ECW based at least in part on the mapping.

In a thirty-ninth aspect, alone or in combination with one or more of the first through thirty-eighth aspects, the configuration is carried in at least one of a system information block, or a radio resource control message.

In a fortieth aspect, alone or in combination with one or more of the first through thirty-ninth aspects, the mapping comprises at least one of a mapping from the CBR to an activation or deactivation of the adaptive ECW, a mapping from the CBR to the at least one parameter of the adaptive ECW, a mapping from the CBR to a minimum parameter value of the at least one parameter of the adaptive ECW, a mapping from the CBR to a maximum parameter value of the at least one parameter of the adaptive ECW, a binary exponential back-off associated with the at least one parameter of the adaptive ECW, or a collision rate associated with the at least one parameter of the adaptive ECW.

In a forty-first aspect, alone or in combination with one or more of the first through fortieth aspects, process <NUM> includes determining that a first traffic priority of a plurality of traffic priorities corresponds to the MAC PDU, wherein selecting the one or more candidate resources of the set of candidate resources that are within the adaptive ECW comprises selecting the one or more candidate resources based at least in part on determining that the first traffic priority of the plurality of traffic priorities corresponds to the MAC PDU, wherein the adaptive ECW is associated with the first traffic priority, and wherein an additional adaptive ECW is associated with a second traffic priority of the plurality of traffic priorities.

In a forty-second aspect, alone or in combination with one or more of the first through forty-first aspects, the adaptive ECW is associated with a first bandwidth of a plurality of bandwidths corresponding to the set of candidate resources, and an additional adaptive ECW is associated with a second bandwidth of the plurality of bandwidths.

In a forty-third aspect, alone or in combination with one or more of the first through forty-second aspects, process <NUM> includes sending, using a MAC layer of the UE, a sidelink sensing request to a physical layer of the UE, wherein the sidelink sensing request indicates, based at least in part on the adaptive ECW, a resource selection window (RSW).

In a forty-fourth aspect, alone or in combination with one or more of the first through forty-third aspects, the sidelink sensing request indicates a first time period and a second time period, wherein the first time period comprises an offset between a resource selection trigger and the RSW and the second time period comprises a width of the RSW.

In a forty-fifth aspect, alone or in combination with one or more of the first through forty-fourth aspects, the second time period comprises a packet data budget associated with the MAC PDU.

In a forty-sixth aspect, alone or in combination with one or more of the first through forty-fifth aspects, the sidelink sensing request indicates the RSW based at least in part on an additional adaptive ECW, wherein the adaptive ECW is associated with an initial HARQ transmission, and wherein the additional adaptive ECW is associated with a retransmission of the initial HARQ transmission.

In a forty-seventh aspect, alone or in combination with one or more of the first through forty-sixth aspects, the sidelink sensing request indicates an additional RSW based at least in part on an additional adaptive ECW, wherein the adaptive ECW is associated with an initial HARQ transmission, and wherein the additional adaptive ECW is associated with a retransmission of the initial HARQ transmission.

In a forty-eighth aspect, alone or in combination with one or more of the first through forty-seventh aspects, the adaptive ECW is associated with an initial HARQ transmission, and process <NUM> further comprises sending, using the MAC layer of the UE, an additional sidelink sensing request to the physical layer of the UE, wherein the additional sidelink sensing request indicates, based at least in part on an additional adaptive ECW, an additional RSW, wherein the additional adaptive ECW is associated with a retransmission of the initial HARQ transmission.

<FIG> is a block diagram of an example apparatus <NUM> for wireless communication. The apparatus <NUM> may be a UE, or a UE may include the apparatus <NUM>. In some aspects, the apparatus <NUM> includes a reception component <NUM> and a transmission component <NUM>, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus <NUM> may communicate with another apparatus <NUM> (such as a UE, a base station, or another wireless communication device) using the reception component <NUM> and the transmission component <NUM>. As further shown, the apparatus <NUM> may include a communication manager <NUM>, among other examples.

In some aspects, the apparatus <NUM> may be configured to perform one or more operations described herein in connection with <FIG>. Additionally, or alternatively, the apparatus <NUM> may be configured to perform one or more processes described herein, such as process <NUM> of <FIG>. In some aspects, the apparatus <NUM> and/or one or more components shown in <FIG> may include one or more components of the UE described above in connection with <FIG>. Additionally, or alternatively, one or more components shown in <FIG> may be implemented within one or more components described above in connection with <FIG>. Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of the component.

The communication manager <NUM> may select, for a sidelink transmission over an unlicensed band and associated with a MAC PDU, one or more candidate resources of a set of candidate resources that are within an adaptive ECW. The communication manager <NUM> may adjust at least one parameter of the adaptive ECW to determine an adjusted at least one parameter based at least in part on a channel access output associated with the one or more candidate resources. In some aspects, the communication manager <NUM> may include a demodulator, a MIMO detector, a receive processor, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with <FIG>. The transmission component <NUM> may transmit the MAC PDU using the one or more candidate resources or an additional one or more candidate resources, wherein the additional one or more candidate resources are selected based at least in part on the adjusted at least one parameter.

Claim 1:
A user equipment, UE (<NUM>, <NUM>, <NUM>) for wireless communication, comprising:
a memory; and
one or more processors, coupled to the memory, configured to:
select (<NUM>), for a sidelink transmission over an unlicensed band and associated with a medium access control, MAC protocol data unit, PDU, one or more candidate resources of a set of candidate resources that are within an adaptive effective contention window, ECW;
adjust (<NUM>) at least one parameter of the adaptive ECW to determine an adjusted at least one parameter based at least in part on a channel access output associated with the one or more candidate resources, wherein the channel access output comprises an indication of channel access success or channel access failure and wherein the user equipment is configured to adjust the at least one parameter by increasing the adaptive ECW for a channel access failure and decreasing the adaptive ECW when channel access is successful; and
transmit (<NUM>) the MAC PDU using the one or more candidate resources or an additional one or more candidate resources, wherein the additional one or more candidate resources are selected based at least in part on the adjusted at least one parameter.