Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may select, from an available resource pool, one or more resources for transmitting a packet on a channel. The UE may determine that a new shared channel occupancy time (COT) has been initiated on the channel. The UE may adapt at least one resource of the one or more resources for transmitting the packet based at least in part on determining that the new shared COT has been initiated. Numerous other aspects are provided.

Abstract: Certain aspects of the present disclosure provide techniques for bit interleaving for sidelink communication with interlaced waveform. A method that may be performed by a user equipment (UE) includes mapping first bits and second bits to resource blocks (RBs) such that the first bits are mapped to first subcarriers of the RBs, a first subset of the second bits are mapped to the first subcarriers, and a second subset of the second bits are mapped to second subcarriers of the REs; and transmitting the first bits and the second bits via the RBs according to the mapping.

Abstract: Channel access for sidelink hybrid automatic repeat request (HARQ) feedback transmission in unlicensed spectrum may be performed. A receiving UE may receive a first transmission from a transmitting UE, and, upon reception of a second transmission from the transmitting UE, may transmit a HARQ feedback transmission to the transmitting UE to indicate decoding of the first transmission. Techniques described herein allow coordination between the receiving UE and the transmitting UE for consistent HARQ feedback in the unlicensed spectrum.

Abstract: In one aspect, a method of wireless communication includes receiving, by a user equipment (UE), a sidelink transmission in a first slot of an unlicensed channel The method also includes performing, by the UE, a Channel Access (CA) operation for a hybrid automatic repeat request (HARQ) feedback transmission in a second slot for the sidelink transmission, where the second slot is one of multiple slots configured for HARQ feedback for the sidelink transmission. The method further includes transmitting, by the UE, HARQ feedback transmission in the second slot based on successfully performing the CA operation. Other aspects and features are also claimed and described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive information identifying a shared channel occupancy for a packet transmission resource and a hop counter value associated with the shared channel occupancy. The user equipment may determine whether to transmit one or more packets in the shared channel occupancy based at least in part on the hop counter value associated with the shared channel occupancy. Numerous other aspects are provided.

Abstract: Certain aspects of the present disclosure provide techniques for resource allocation with collision indication for sidelink communication. A method that may be performed by a first user equipment (UE) includes receiving a first sidelink transmission from a second UE indicating a first resource reservation; receiving a second sidelink transmission from a third UE indicating a second resource reservation; and transmitting, to at least the second UE, feedback comprising: hybrid automatic retransmission request (HARQ) feedback regarding the first sidelink transmission; and an indication of whether a collision is detected by the first UE between the first resource reservation and the second resource reservation.

Abstract: A user equipment (UE) communicates on a shared channel using sidelink transmissions. The UE determines a channel access priority for the sidelink transmission based on a channel access priority for the UE, a channel access priority associated with a packet priority of the sidelink transmission, a congestion level for the channel, or a remaining time in a packet delay budget of the sidelink transmission. The UE performs a channel access procedure based on the channel access priority for the sidelink transmission to assess that the channel is clear prior to transmitting the sidelink transmission, and transmits the sidelink transmission on the channel.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may determine resource selection priority levels associated with available resources for sidelink signaling in an unlicensed radio frequency spectrum band, the resources selection priority levels may be determined based on resource reservation information of the available resources, a time domain location of the available resources, or both. For example, a first resource of the available resources may be associated with a higher priority than a second resource of the available resources in resource selection. The UE may select one or more resources for the sidelink signaling from the available resources based on the resource selection priority levels associated with the available resources. The UE may transmit the sidelink signaling on the unlicensed radio frequency spectrum band using the one or more selected resources.

Abstract: Certain aspects of the present disclosure provide techniques for sidelink communications in an unlicensed spectrum. A method that may be performed by a user equipment (UE) and a base station (BS) includes sensing, prior to a start of a time window, a frequency band to determine whether the frequency band is idle, the time window divided in time into a plurality of time periods, the frequency band divided in time across multiple of the plurality of time periods into a corresponding plurality of resources comprising one or more unassigned resources and one or more assigned resources assigned to one or more other wireless communication devices for wireless communication.

Abstract: Certain aspects of the present disclosure provide techniques for slot format for sidelink communication. A method that may be performed by a user equipment (UE) includes transmitting a data signal; refraining from transmitting during a gap portion occurring in time after the transmission of the data signal, wherein the gap portion has a duration less than or equal to a threshold; receiving a feedback signal after the gap portion, wherein the feedback signal comprises at least a signal and hybrid automatic retransmission request (HARQ) feedback for the data signal; receiving another signal; and adjusting a gain applied to the other signal based on the signal.

Abstract: Methods, systems, and devices for wireless communications are described. A transmitting device and a receiving device may communicate sidelink messages of a second radio access technology (RAT) using a sidelink resource pool signaled using a first RAT. For example, the receiving UE may receive a sidelink control channel associated with the first RAT (e.g., Long Term Evolution (LTE)), may determine a set of time and frequency resources indicated by the sidelink control channel, and then may monitor the set of time and frequency resources to receive a sidelink message associated with the second RAT (e.g., New Radio (NR)). In some implementations, the set of time and frequency resource may be indicated that they may be used for the second RAT via a field in the sidelink control channel or via an additional sidelink message associated with the second RAT transmitted with the sidelink control channel.

Abstract: Techniques for wireless communications are described. A communication device, such as a user equipment (UE) may determine a resource usage level in a wireless communications system. Additionally or alternatively, the UE may determine a transmission property associated with sidelink communication at the UE. The UE may adjust, based on the determined resource usage level in the wireless communications system or the determined transmission property associated with the sidelink communication at the UE, or a combination thereof, a sensing mode of a sensing procedure or a sensing parameter of the sensing procedure, or a combination thereof. In some examples, the UE may identify a set of resources used for the sidelink communication at the UE based on the adjusted sensing mode or the adjusted sensing parameter, or a combination thereof. The UE may perform the sidelink communication based on the sensing mode or the sensing parameter, or a combination thereof.

Abstract: Methods, systems, and devices for wireless communications are described in which a user equipment (UE) may reserve one or more time frequency resources in an unlicensed frequency spectrum band for one or more sidelink transmissions. The UE may reserve the time frequency resources through a sidelink message transmitted in a first slot of a shared channel occupancy (CO). The UE may monitor a subset of slots before the reserved time frequency resources for sidelink transmissions from other UEs sharing the CO. The monitoring of the subset of slots may include decoding control messages or control information in each of the subset of slots, a reference signal received power (RSRP) measurement of sidelink transmissions in the subset of slots, channel sensing with energy detection in a sensing window, or a combination thereof. The UE may communicate in the reserved slot based on the monitoring.

Abstract: Certain aspects of the present disclosure provide techniques for sidelink communications in an unlicensed spectrum. A method that may be performed by a first user equipment (UE) of a plurality of UEs includes sensing a frequency band to determine whether the frequency band is idle, the sensing occurring prior to a first time period. In some examples, the method may include transmitting, by the first UE, one or more signals over the frequency band during the first time period based on determining that the frequency band is idle, the one or more signals indicating that the frequency band is reserved for wireless communication between the plurality of UEs during the first time period.

Abstract: Certain aspects of the present disclosure provide techniques for enhanced feedback transmission for sidelink communication in unlicensed spectrum.

Abstract: Certain aspects of the present disclosure provide techniques for unlicensed channel occupancy time sharing based on received signal strength. A method that may be performed by a first user equipment (UE) includes receiving a first transmission from a second UE, the first transmission indicating the second UE has acquired a frequency band for a channel occupancy time (COT). The method may also include transmitting a signal within the frequency band during the COT in response to a signal strength of the first transmission as received by the first UE being greater than at least one threshold.

Abstract: Certain aspects of the present disclosure provide techniques for sidelink communications in an unlicensed spectrum. A method that may be performed by a user equipment (UE) includes measuring, starting at least at a start time of a time interval, a frequency band to determine whether the frequency band is idle, the time interval including a plurality of time periods. While measuring the frequency band, decoding, by the UE, any signals received on the frequency band to determine if a clear-to-send (CTS) signal is received over the frequency band.

Abstract: Certain aspects of the present disclosure provide techniques for slot format for sidelink communication. A method that may be performed by a user equipment (UE) includes refraining from transmitting during a gap portion of a first symbol in time of a sidelink transmission, wherein the first symbol comprises the gap portion and a signal portion; transmitting a signal during the signal portion of the first symbol; and transmitting a data signal of the sidelink transmission in at least one second symbol subsequent in time to the first symbol in the sidelink transmission.

Abstract: Certain aspects of the present disclosure provide a method for wireless communications by a transmitter UE. The method generally includes transmitting data to at least one receiver UE in an unlicensed spectrum used for sidelink communication, determining if a resource in a slot is available for the at least one receiver UE to provide acknowledgment feedback for the data transmission, and transmitting a reservation signal in the slot if the resource is determined to be available.

Abstract: Certain aspects of the present disclosure provide techniques for carrier selection for sidelink communications in an unlicensed spectrum. A method that may be performed by a first sidelink user equipment (UE) includes determining one or more carriers, from a set of configured carriers, in an unlicensed spectrum to use for communicating with a second sidelink UE and communicating with the second sidelink UE using the determined one or more carriers.