Patent Description:
Aspects of wireless communication may comprise direct communication between devices, such as in V2X and/or other D2D communication. There exists a need for further improvements in V2X and/or other D2D technology.

<CIT> relates to distributed joint access of an unlicensed sidelink channel wherein each sidelink device may perform independent and asynchronous listen before talk (LBT) of the unlicensed sidelink channel with a respective back-off timer value.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus of a wireless device are provided. The wireless device may initiate an LBT sidelink sensing procedure including initiating an LBT timer to run for at least a minimum sensing duration in a channel. The wireless device may detect one or more signals in the channel during the LBT sidelink sensing procedure. The wireless device may allow the LBT timer to continue to run, such as based at least in part on determining that the one or more signals are one or more sidelink signals.

By way of example, and not limitation, such computer-readable media can include 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 types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

While aspects and implementations are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, implementations and/or uses may come about via integrated chip implementations and other nonmodule-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also include additional components and features for implementation and practice of claimed and described aspect. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor(s), interleaver, adders/summers, etc.). It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

A sidelink network, such as a V2X network, may be deployed in an unlicensed spectrum. To facilitate communications in the unlicensed spectrum, LBT sidelink sensing procedures may be applied prior to sidelink transmissions, such as V2X transmissions, in order to avoid collisions without other transmissions in the unlicensed spectrum. The term "LBT sidelink sensing procedure" may refer to a sensing procedure used for a sidelink transmission, i.e., a direct communication between two UEs. The other transmissions may be based on other radio access technologies (RAT)s. LBT sensing is based on energy detection, and the channel for which sensing is performed may be identified as busy due to other sidelink, e.g., V2X activities. However, identifying the channel as busy and canceling/delaying sidelink, e.g., V2X transmissions due to V2X activities may be inefficient because sidelink activities may be designed to avoid the collisions without relying on the LBT. For example, in a mode <NUM> sidelink resource allocation, or decentralized resource allocation mode, a sidelink UE may perform a sidelink sensing and reservation procedure. In order to avoid collisions with sidelink signals, the UE may apply sensing/reservation of resources based on sidelink. For example, the UE may monitor for sidelink reservations from other devices and may select transmission resources that avoid the reserved sidelink resources of the other devices. The cancellation/delay of sidelink transmissions reduced the efficiency of the sidelink network such as interrupting procedures such as resource selection/reservation and introduces latency. Aspects described herein provide a more efficient LBT sidelink sensing procedure for sidelink devices by considering whether a detected signal is a sidelink signal. For example, when performing LBT, if a UE detects an energy level that meets a threshold, the UE switches the LBT state to a frozen state, e.g., freezing an LBT timer under the LBT procedure. As presented herein, the UE may further consider the source of the detected energy, and if the energy is due to a sidelink transmission, the UE may continue to run the LBT timer instead of freezing the LBT timer. Thus, the LBT of a sidelink device may continue uninterrupted by the presence of sidelink signals.

As illustrated in <FIG>, the UE <NUM>, Road Side Unit (RSU) <NUM>, or other sidelink such as V2X device, may comprise an LBT component <NUM> configured to initiate an LBT sidelink sensing procedure including initiating an LBT timer to run for at least a minimum sensing duration in a channel. The LBT component <NUM> may be further configured to detect one or more signals in the channel during the LBT sidelink sensing procedure. The LBT component <NUM> may be further configured to allow the LBT timer to continue to run, such as based at least in part on determining that the one or more signals are one or more sidelink signals.

A link between a UE <NUM> and a base station <NUM> or <NUM> may be established as an access link, e.g., using a Uu interface. Other communication may be exchanged between wireless devices based on sidelink. For example, some UEs <NUM> may communicate with each other directly using a device-to-device (D2D) communication link <NUM>. In some examples, the D2D communication link <NUM> may use the DL/UL WWAN spectrum.

Some examples of sidelink communication may include vehicle-based communication devices that can communicate from vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from the vehicle-based communication device to road infrastructure nodes such as a Road Side Unit (RSU)), vehicle-to-network (V2N) (e.g., from the vehicle-based communication device to one or more network nodes, such as a base station), vehicle-to-pedestrian (V2P), cellular vehicle-to-everything (C-V2X), and/or a combination thereof and/or with other devices, which can be collectively referred to as vehicle-to-anything (V2X) communications. Sidelink communication may be based on V2X or other D2D communication, such as Proximity Services (ProSe), etc. In addition to UEs, sidelink communication may also be transmitted and received by other transmitting and receiving devices, such as Road Side Unit (RSU) <NUM>, etc. Sidelink communication may be exchanged using a PC5 interface, such as described in connection with the example in <FIG>. Although the following description, including the example slot structure of <FIG>, may provide examples for sidelink communication in connection with <NUM> NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

Similarly, beamforming may be applied for sidelink communication, e.g., between UEs.

Although this example is described for the base station <NUM> and UE <NUM>, the aspects may be similarly applied between a first and second device (e.g., a first and second UE) for sidelink communication.

<FIG> includes diagrams <NUM> and <NUM> illustrating example aspects of slot structures that may be used for sidelink communication (e.g., between UEs <NUM>, RSU <NUM>, etc.). The slot structure may be within a <NUM>/NR frame structure in some examples. In other examples, the slot structure may be within an LTE frame structure. Although the following description maybe focused on <NUM> NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies. The example slot structure in <FIG> is merely one example, and other sidelink communication may have a different frame structure and/or different channels for sidelink communication. Diagram <NUM> illustrates a single resource block of a single slot transmission, e.g., which may correspond to a <NUM> transmission time interval (TTI). A physical sidelink control channel may be configured to occupy multiple physical resource blocks (PRBs), e.g., <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> PRBs. The PSCCH may be limited to a single sub-channel. A PSCCH duration may be configured to be <NUM> symbols or <NUM> symbols, for example. A sub-channel may include <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> PRBs, for example. The resources for a sidelink transmission may be selected from a resource pool including one or more subchannels. As a nonlimiting example, the resource pool may include between <NUM>-<NUM> subchannels. A PSCCH size may be established for a resource pool, e.g., as between <NUM>-<NUM> % of one subchannel for a duration of <NUM> symbols or <NUM> symbols. The diagram <NUM> in <FIG> illustrates an example in which the PSCCH occupies about <NUM>% of a subchannel, as one example to illustrate the concept of PSCCH occupying a portion of a subchannel. The physical sidelink shared channel (PSSCH) occupies at least one subchannel. The PSCCH may include a first portion of sidelink control information (SCI), and the PSSCH may include a second portion of SCI in some examples.

Each time slot may include a resource block (RB) (also referred to as physical RBs (PRBs)) that extends <NUM> consecutive subcarriers. As illustrated in <FIG>, some of the REs may include control information in PSCCH and some REs may include demodulation RS (DMRS). At least one symbol maybe used for feedback. <FIG> illustrates examples with two symbols for a physical sidelink feedback channel (PSFCH) with adjacent gap symbols. A symbol prior to and/or after the feedback may be used for turnaround between reception of data and transmission of the feedback. The gap enables a device to switch from operating as a transmitting device to prepare to operate as a receiving device, e.g., in the following slot. Data may be transmitted in the remaining REs, as illustrated. The data may include the data message described herein. The position of any of the data, DMRS, SCI, feedback, gap symbols, and/or LBT symbols maybe different than the example illustrated in <FIG>. Multiple slots may be aggregated together in some aspects.

<FIG> is a block diagram of a first wireless communication device <NUM> in communication with a second wireless communication device <NUM>. In some examples, the devices <NUM> and <NUM> may communicate based on V2X or other D2D communication. The communication may be based, e.g., on sidelink using a PC5 interface. The devices <NUM> and the <NUM> may comprise a UE, an RSU, a base station, etc. Packets may be provided to a controller/processor <NUM> that implements layer <NUM> and layer <NUM> functionality.

The memory <NUM> maybe referred to as a computer-readable medium.

<FIG> illustrates an example <NUM> of wireless communication between devices based on V2X, D2D, or other sidelink communication. The communication may be based on a slot structure comprising aspects described in connection with <FIG>. For example, transmitting UE <NUM> may transmit a transmission <NUM>, e.g., comprising a control channel and/or a corresponding data channel, that may be received by receiving UEs <NUM>, <NUM>, <NUM>. A control channel may include information for decoding a data channel, e.g., including reservation information. The reservation information may indicate time and frequency resources that the UE <NUM> intends to use for a transmission. UEs that receive the control channel may use the reservation information to avoid interference by refraining from transmitting on the reserved resources. For example, the UE <NUM> may indicate the number of TTIs, as well as the RBs that will be occupied by the data transmission, e.g., in a control message. The UEs <NUM>, <NUM>, <NUM>, <NUM> may each be capable of operating as a transmitting device in addition to operating as a receiving device. Thus, UEs <NUM>, <NUM> are illustrated as transmitting transmissions <NUM>, <NUM>. The transmissions <NUM>, <NUM>, <NUM> may be broadcast or multicast to nearby devices. For example, UE <NUM> may transmit communication intended for receipt by other UEs within a range <NUM> of UE <NUM>. Additionally/alternatively, RSU <NUM> may receive communication from and/or transmit communication <NUM> to UEs <NUM>, <NUM>, <NUM>, <NUM>. One or more of the UEs <NUM>, <NUM>, <NUM>, or <NUM> may include an LBT component <NUM>, such as described in connection with <FIG>.

A sidelink network, such as a CV2X network, may be deployed in an unlicensed spectrum. To facilitate communications in the unlicensed spectrum, LBT sidelink sensing procedures may be applied prior to transmissions in order to determine resources occupied by transmissions from other devices and to avoid collisions. The other transmissions may be based on different RATs. Because LBT sensing may be based on energy detection, the monitors channel being may be identified as busy due to other sidelink, such as V2X transmissions. However, identifying the channel as busy with the LBT process, and canceling/delaying sidelink transmissions based on sidelink, such as V2X activities may be inefficient because sidelink activities may be designed to avoid the collisions between sidelink communication even without the LBT sidelink sensing procedure. Thus, the LBT sidelink sensing procedure may be employed by a sidelink device in order to share the unlicensed spectrum with other RATs. Such inefficiency in delaying sidelink transmission due to the detection of sidelink signals during an LBT sidelink sensing procedure may reduce performance of the sidelink network. For example, the delay may interrupt sidelink sensing and reservation procedures.

A sidelink device may generate a new packet and may select a resource (subchannel/slot) for the sidelink transmission that may be preceded by an LBT sidelink sensing procedure. The LBT sidelink sensing procedure may be associated with an LBT timer that may be frozen during the LBT sidelink sensing procedure. The selected slot may be referred to as a target slot for the sidelink transmission. The start of the LBT sensing may be aligned such that successful termination of the LBT sidelink sensing procedure coincides with the start of the "target" slot. Therefore, the device may have an estimate of a length of the LBT (energy) sensing duration. For example, the device may consider a minimum sensing duration assuming operation in an idle channel and initiate the LBT sidelink sensing procedure accordingly. After initiating the LBT sidelink sensing procedure, the LBT timer may start to run. After the LBT timer runs for the minimum sensing duration, the LBT sidelink sensing procedure may complete and the device may transmit the packet. Because the device assumed an idle channel for initializing its LBT procedure, any detected transmission during the LBT sidelink sensing procedure may freeze the LBT timer and may render the LBT sidelink sensing procedure unable to terminate on time. Therefore, if the LBT sidelink sensing procedure is not able to finish before the target slot due to the detected transmission(s), the target slot may be abandoned (i.e., no transmission may be performed in that slot as was originally intended when the resource was selected).

<FIG> illustrates an example <NUM> of sidelink (V2X) device communication with LBT sensing. As illustrated in <FIG>, in order to transmit a packet, a V2X device 502A may initiate LBT sensing at <NUM> after the packet arrives. The V2X device may initiate the LBT sensing such that without interference the LBT sensing period may terminate at the start of the target slot <NUM> (slot n), enabling the transmission of the packet. A second V2X device 502B may transmit a communication <NUM>, or signal, at slot n-<NUM>. An energy associated with the communication <NUM> may be detected by the V2X device 502A and a timer of the LBT sidelink sensing procedure may temporarily "freeze" (i.e., cease/pause due to a communication) at <NUM> and resume at <NUM>, rendering the V2X device 502A unable to complete the LBT sidelink sensing procedure before the target slot <NUM>. Instead, the LBT sidelink sensing procedure may end at <NUM>, i.e., after the start of the target slot <NUM>, and the target slot <NUM> may not be used for the packet transmission.

To facilitate more efficient LBT sidelink sensing procedures, as illustrated in example <NUM> in <FIG>, a V2X device 602A may determine an energy level for received communication/signals and identify the origin of the communication/signals that are detected during an LBT sensing period. As illustrated in <FIG>, the V2X device 602A may initiate the LBT sensing period at <NUM>. The V2X device 602A may detect a communication <NUM> from a V2X device 602B. The 602A may detect communication <NUM> by sensing the energy and then determine that the communication <NUM> is a V2X communication after successfully decoding sidelink control information (SCI) in the communication <NUM>. Because the V2X device 602A successfully decoded SCI in the communication <NUM>, the V2X device 602A may continue the LBT timer. The LBT sidelink sensing procedure may end at <NUM>, i.e., prior to the start of the target slot <NUM>, and the V2X device 602A may successfully transmit the packet at target slot <NUM>. In some examples, the V2X device 602A may be a CV2X device, and may continue the LBT timer if the energy is due to a CV2X transmission.

Operations illustrated in the example <NUM> may lead to aggressive channel utilization by V2X devices. As illustrated in example <NUM> of <FIG>, because the V2X device 702A will continue the LBT timer starting at <NUM> after detecting communications 722A, 722B, 722C, 722D, 722E, and 722F from other V2X devices 702B, the V2X devices may use the channel continuously. Such continuous usage may affect other V2X devices and non-V2X devices because the channel may be continuously occupied by V2X devices.

To reduce such aggressive channel utilization by V2X devices, as illustrated in example <NUM> in <FIG>, a V2X device 802A may be configured to count the number of slots where SCI is decoded while continuing the LBT timer starting at <NUM>. For example, based on the communication <NUM> from a V2X device 802B, the V2X device 802A may count two slots where the SCI is decoded. After the number of slots where SCI is decoded reaches a threshold of two, the V2X device 802A may decode another SCI in communication <NUM> and may freeze the LBT timer at <NUM> and resume the LBT timer at <NUM> accordingly.

In some aspects, as illustrated in example <NUM> in <FIG>, a V2X device 902A may be configured to continue the LBT timer starting at <NUM> if isolated slots (i.e., slots that are not immediately preceded or followed by an active V2X slot) with SCI are detected. For example, the V2X device 902A may decode SCI in communication 920A and communication 920B from V2X device 902B and continue the LBT timer because the communication 920A and the communication 920B are associated with isolated slots. After the V2X device 902A decodes SCI in communication <NUM> and detects an immediately following slot with SCI in the communication <NUM>, the V2X device 902A may freeze the LBT timer at <NUM>. In some aspects, instead of determining isolated slots, the V2X device may determine the number of consecutive slots with SCI and freeze the timer after a threshold is reached (threshold = <NUM> for isolated slot aspect).

In some aspects, as illustrated in example <NUM> in <FIG>, a V2X device 1002A may be configured to continue the LBT timer starting at <NUM> after detecting V2X communication as part of channel occupancy time (COTs) and if a number of COTs has not reached a threshold. A V2X device 1002B that identified the channel as idle (after performing LBT) and begins transmission may initiate a "channel occupancy" with duration COT that may span multiple V2X slots. The COT duration may be indicated in SCI and the SCI may indicate that one or more slots that are associated with the same COT. If another V2X device detects the COT, e.g., by decoding the SCI, and determines that the COT is not fully utilized, the V2X device may transmit within the COT without LBT and indicate the remaining COT duration in SCI. In some aspects, the V2X device 1002A may be configured to ignore (i.e., continuing without freezing the LBT timer) a configured number of V2X initiated COTs. For example, if the V2X device 1002A is configured to ignore <NUM> COTs, the V2X device 1002A may ignore COT <NUM> at communication <NUM> and COT <NUM> at communication <NUM> and freeze the LBT timer at <NUM> after detecting a third COT at <NUM>. The V2X device 1002A may continue the LBT timer at <NUM>.

In some aspects, as illustrated in example <NUM> in <FIG>, a V2X device 1102A may be configured to continue the LBT timer starting at <NUM> after detecting two isolated active V2X slots 1120A and 1120B that is used by a V2X device 1102B. After detecting a third active V2X isolated slot 1120C, the V2X device 1102A may determine to stop the LBT timer at <NUM>. The term "LBT sensing cycle" may be used to refer to a continuous cycle where the LBT timer is running, e.g., between <NUM> and <NUM>. For each LBT cycle, the V2X device 1102A may freeze the LBT timer based on a different set of rules. For example, for the cycle between <NUM> and <NUM>, the V2X device 1102A may stop the LBT timer based on a threshold of three isolated active V2X slots. After resuming the LBT timer, the V2X device 1102A may adjust the rules for freezing the LBT timer. In some aspects, the adjustments may be based on the type of activity (e.g., whether it was a V2X signal or a non-CV2X signal) that caused the LBT timer to freeze. In some aspects, the adjustments may be based on the number of times where the LBT timer has stopped during the current LBT sidelink sensing procedure. For example, at a second LBT sensing cycle starting after <NUM>, the V2X device 1102A may be configured to freeze the LBT timer at <NUM> after detecting two isolated active V2X slots at 1122A and 1122B. At a third LBT sensing cycle starting after <NUM>, the V2X device 1102A maybe configured to freeze the LBT timer at <NUM> after detecting one isolated active V2X slot at <NUM>. At <NUM>, the LBT timer may expire and the V2X device 1102A may transmit the packet.

Because the V2X SCI may be distributed over the first OFDM symbols of the slot, a V2X receiver may wait for some time after a V2X transmission has started in order to be able to decode the SCI. Therefore, when energy is detected at the very start of a slot, the LBT of a V2X device may first assume that the energy is V2X-originated and continue as if no signal is present. If an SCI is decoded later in the slot, the LBT may continue. If the SCI is not decoded by the expected time, the LBT timer may freeze as the V2X device may treat the signal as a non-V2X signal. When the LBT sidelink sensing procedure is resumed, it may be continued from the state at the slot start of the detected non-V2X signal. Similarly, if the V2X device determines to freeze the LBT timer because of a COT, the LBT timer may be continued from the state at the beginning of the COT.

V2X wireless devices may initiate a new LBT sidelink sensing procedure with a set of rules for the LBT timer being the same as or different from the previous LBT sidelink sensing procedure. For example, for a LBT first initiates it may be set to ignore (i.e., continuing without freezing LBT timer after detecting) up to two V2X slots, for the next sensing procedure it may ignore one V2X slot, and for the following procedures, it may not ignore V2X slots. The new set of rules may depend on the type of activity that interrupted the previous procedure (i.e., whether it was a V2X signal or a non-V2X signal that interrupted the LBT). Although <FIG> are described in connection with V2X communication, the aspects may be applied to other types of sidelink communication in the unlicensed spectrum or to other types of communication in the unlicensed spectrum that includes a separate mechanism than LBT for avoiding collisions.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a sidelink, such as a V2X wireless device (e.g., the UE <NUM>, the wireless device 502A, the wireless device 602A, the wireless device 702A, the wireless device 802A, the wireless device 902A, the wireless device 1002A, the apparatus <NUM>). The method may enable the wireless device to ignore one or more V2X signals during LBT to facilitate more efficient LBT sidelink sensing procedures.

At <NUM>, the wireless device initiates an LBT sidelink sensing procedure including initiating an LBT timer to run for at least a minimum sensing duration in a channel. For example, the initiation <NUM> may be performed by an LBT initiation component <NUM> of <FIG>. The initiation <NUM> may correspond to the LBT initiation <NUM>, the LBT initiation <NUM>, the LBT initiation <NUM>, the LBT initiation <NUM>, the LBT initiation <NUM>, or the like in <FIG>.

At <NUM>, the wireless device detects one or more signals in the channel during the LBT sidelink sensing procedure. For example, the detection <NUM> maybe performed by a signal detection component <NUM> of <FIG>. The detection <NUM> may correspond to the detections of the communication <NUM>, the communications 722A-F, the communication <NUM>, the communication 920A/B, the communication <NUM>, or the communication <NUM> in <FIG>. In some aspects, detecting the one or more signals in the channel during the LBT sidelink sensing procedure includes detecting energy.

At <NUM>, the wireless device allows the LBT timer to continue to run, e.g., based at least in part on determining that the one or more signals are one or more sidelink signals. For example, the determination <NUM> may be performed by a continuation determination component <NUM> of <FIG>. In some aspects, the wireless device determines that the one or more signals are one or more sidelink signals based on successfully decoding sidelink control information (SCI) associated with the one or more signals. The device may determine to continue the LBT timer based on determining that the one or more signals are the one or more sidelink signals. The wireless device may determine that the one or more signals are one or more sidelink signals after decoding an SCI for each slot associated with each signal. In some aspects, determining to continue the LBT timer may be based on if the one or more signals are sidelink signals, e.g., as described in connection with <FIG> and <FIG>. In some aspects, determining to continue the LBT timer may further include determining that the one or more signals are one or more sidelink signals that satisfy a set of sidelink metrics (e.g., rules for freezing the LBT timer as described in connection with <FIG>) In some aspects, determining to continue the LBT timer after determining that the one or more signals are the one or more sidelink signals that satisfy a set of sidelink metrics further includes counting a number of slots where the SCI is decoded and determining that the one or more signals satisfy the set of sidelink metrics until a slot number threshold is reached, e.g., as described in connection with <FIG>. In some aspects, determining to continue the LBT timer after determining that the one or more signals are the one or more sidelink signals that satisfy a set of sidelink metrics further includes determining that the one or more signals are associated with one or more isolated sidelink slots that are not immediately preceded or followed by an active sidelink slot (i.e., a V2X slot over which a V2X transmission is detected, e.g., as described in connection with <FIG>). In some aspects, allowing the LBT timer to continue to run further includes determining that one or more consecutive slots associated with the one or more signals last shorter than a duration. In some aspects, determining that the one or more consecutive slots associated with the one or more signals last shorter than the duration is based on SCI associated with the one or more signals. In some aspects, the one or more signals are associated with a number of channel occupancy times, each channel occupancy time comprising one or more consecutive slots, and wherein allowing the LBT timer to continue to run further includes determining the number of channel occupancy times is less than a threshold, e.g., as described in connection with <FIG>. In some aspects, determining that the number of channel occupancy times is less than the threshold is based on SCI associated with the one or more signals.

At <NUM>, the wireless device detects one or more signals in the channel during the LBT sidelink sensing procedure. For example, the detection <NUM> may be performed by a signal detection component <NUM> of <FIG>. The detection <NUM> may correspond to the detections of the communication <NUM>, the communications 722A-F, the communication <NUM>, the communication 920A/B, the communication <NUM>, or the communication <NUM> in <FIG>. In some aspects, detecting the one or more signals in the channel during the LBT sidelink sensing procedure includes detecting energy.

At <NUM>, the wireless device detects a second set of one or more signals and freezes the LBT timer after determining that the second set of one or more signals are not the one or more sidelink signals that satisfy a first set of sidelink metrics. For example, the determination <NUM> may be performed by a freezing determination component <NUM> of <FIG>. The second set of one or more signals may correspond to the communication <NUM> in <FIG>, the communication <NUM> in <FIG>, the communication <NUM> in <FIG>, or the like.

At <NUM>, the wireless device continues the LBT timer after a configured duration. For example, continuation <NUM> may be performed by the LBT initiation component <NUM>. The continuation <NUM> may correspond to the continuation <NUM>, the continuation <NUM>, or the like in <FIG>. The configured duration may be referred as a "freeze duration". In some aspects, the LBT timer may be continued with a second set of sidelink metrics. The second set of sidelink metrics is based on the one or more signals that are not the one or more sidelink signals that satisfy the first set of sidelink metrics, e.g., as described in connection with <FIG>.

At <NUM>, the wireless device initiates a second LBT sidelink sensing procedure with a second set of sidelink metrics. For example, initiation <NUM> may be performed by the LBT initiation component <NUM> of <FIG>. The second set of sidelink metrics may be the same as or different from the set of sidelink metrics in initiation <NUM>. In some aspects, the second set of sidelink metrics is based on the LBT sidelink sensing procedure (e.g., whether a timer associated with the LBT sidelink sensing procedure was frozen for sidelink or non sidelink signals, the signals that cause the timer to freeze, or the like).

The apparatus <NUM> is a wireless device and includes a baseband unit <NUM>. The baseband unit <NUM> may communicate through a cellular RF transceiver with the UE <NUM>. The baseband unit <NUM> may include a computer-readable medium / memory. The baseband unit <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the baseband unit <NUM>, causes the baseband unit <NUM> to perform the various functions described supra. The computer-readable medium / memory may also be used for storing data that is manipulated by the baseband unit <NUM> when executing software. The baseband unit <NUM> further includes a reception component <NUM>, a communication manager <NUM>, and a transmission component <NUM>. The components within the communication manager <NUM> may be stored in the computer-readable medium / memory and/or configured as hardware within the baseband unit <NUM>. The baseband unit <NUM> may be a component of the device <NUM>/<NUM> and may include the memory <NUM>/<NUM> and/or at least one of the TX processor <NUM>/<NUM>, the RX processor <NUM>/<NUM>, and the controller/processor <NUM>/<NUM>.

The communication manager <NUM> includes an LBT initiation component <NUM> that initiates an LBT sidelink sensing procedure including initiating an LBT timer to run for at least a minimum sensing duration in a channel, e.g., as described in connection with initiation <NUM> and <NUM> of <FIG>, and <NUM> of <FIG>. The communication manager <NUM> may further include a signal detection component <NUM> that detects one or more signals in the channel during the LBT sidelink sensing procedure, e.g., as described in connection with detection <NUM> and detection <NUM> of <FIG>, and <NUM> of <FIG>. The communication manager <NUM> may further include a continuation determination component <NUM> that determines to allow the LBT timer to continue to run, e.g., based at least in part on determining that the one or more signals are one or more sidelink signals, e.g., as described in connection with determination <NUM> of <FIG>, and <NUM> of <FIG>. The communication manager <NUM> may further include a freezing determination component <NUM> that freezes the LBT sidelink sensing procedure after determining that the second set of one or more signals are not the one or more sidelink signals that satisfy a first set of sidelink metrics and continuing the LBT timer after a duration with a second set of sidelink metrics, e.g., as described in connection with determination <NUM> of <FIG>.

In one configuration, the apparatus <NUM>, and in particular the baseband unit <NUM>, includes means for initiating an LBT sidelink sensing procedure including initiating an LBT timer to run for at least a minimum sensing duration in a channel. In some aspects, the apparatus <NUM>, and in particular the baseband unit <NUM>, further includes means for detecting one or more signals in the channel during the LBT sidelink sensing procedure. In some aspects, the apparatus <NUM>, and in particular the baseband unit <NUM>, further includes means for allowing the LBT timer to continue to run. In some aspects, the apparatus <NUM>, and in particular the baseband unit <NUM>, further includes means for detecting a second set of one or more signals and freezing the LBT timer after determining that the second set of one or more signals are not the one or more sidelink signals that satisfy the set of sidelink metrics. In some aspects, the apparatus <NUM>, and in particular the baseband unit <NUM>, further includes means for continuing the LBT timer after a configured duration. In some aspects, the apparatus <NUM>, and in particular the baseband unit <NUM>, further includes means for initiating a second LBT sidelink sensing procedure with a second set of sidelink metrics.

The aforementioned means may be one or more of the aforementioned components of the apparatus <NUM> configured to perform the functions recited by the aforementioned means. As described supra, the apparatus <NUM> may include the TX processor <NUM>/<NUM>, the RX processor <NUM>/<NUM>, and the controller/processor <NUM>/<NUM>. As such, in one configuration, the aforementioned means may be the TX processor <NUM>/<NUM>, the RX processor <NUM>/<NUM>, and the controller/processor <NUM>/<NUM> configured to perform the functions recited by the aforementioned means.

Claim 1:
A method (<NUM>) of wireless communication at a wireless device (<NUM>), comprising:
initiating (<NUM>) a listen before talk, LBT, sidelink sensing procedure including initiating an LBT timer to run for at least a minimum sensing duration in a channel;
detecting (<NUM>) one or more signals in the channel during the LBT sidelink sensing procedure; and
allowing (<NUM>) the LBT timer to continue to run based on the one or more signals being one or more sidelink signals.