Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may obtain a common key. The UE may communicate with one or more other UEs using a lower layer groupcast key that is based at least in part on the common key, a parameter, and at least one of a group identifier or a destination identifier. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may receive, from a second UE, a first sidelink synchronization signal (SLSS) at a first transmission-reception point (TRP) and a second TRP different from the first TRP. The first UE may perform a first set of measurements on the first SLSS received at the first TRP and a second set of measurements on the first SLSS received at the second TRP. The first UE may then transmit, to a third UE, a second SLSS based at least in part on the first set of measurements, the second set of measurements, or both, satisfying one or more measurement thresholds.

Abstract: A configuration to enable a UE operating as a full duplex device to transmit or receive feedback to or from other full duplex wireless devices or half duplex wireless devices. The apparatus allocates one or more sets of feedback resources, in association with a second UE, for transmission or reception of feedback message. The apparatus determines to transmit or receive the feedback message on a first resource set of the one or more sets of feedback resources based on a priority of the feedback message or a priority of a feedback resource set to transmit or receive a feedback message. The apparatus transmits or receives the feedback message based on the priority of the feedback message or the feedback resource set.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may identify one or more spectral efficiency ranges that are to be used to select a modulation and coding scheme (MCS) for a sidelink communication. The UE may transmit the sidelink communication using the MCS selected based at least in part on the one or more spectral efficiency ranges. Numerous other aspects are provided.

Abstract: In one aspect, a method includes determining, by a user equipment (UE), a channel busy ratio (CBR) window for a CBR measurement for one or more resources; determining, by the UE, a CBR measurement value for the CBR window and for the one or more resources; determining, by the UE, a channel occupancy ratio (CR) window based on a first number of subframes used for a history of past transmissions and based on a second number of subframes used for future planned transmissions and corresponding retransmissions; and determining, by the UE, a CR value for the CR window based on subchannels used for the one or more resources for the first number of subframes and based on subchannels estimated for the one or more resources for the second number of subframes. In another aspect, a method includes determining a CR window based on a CBR measurement value.

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 wireless communications device, such as a roadside unit (RSU) or a user equipment (UE), may transmit a network coding packet on a sidelink to perform an efficient retransmission for multiple packets. In some systems, a base station may coordinate sidelink communications between devices, such as by granting resources for the devices to communicate on the sidelink. The device which transmits the network coding packet may request resources from the base station, and the base station may grant resources for the device to transmit the network coding packet. These techniques may be implemented to prevent the base station from granting resources to the original source UEs for retransmission.

Abstract: A method of wireless communication by a transmitting sidelink user equipment (UE) determines at least one quasi-co-location (QCL) relationship between antenna ports of the transmitting sidelink UE. The QCL relationship corresponds to carrier frequency offset (CFO), average delay, delay spread, Doppler shift, and/or Doppler spread across the antenna ports of the transmitting sidelink UE. Each port maps to a different transmission and reception point (TRP). The method also indicates the QCL relationship(s) to a receiving sidelink UE. A method of wireless communication by a receiving sidelink UE receives a message from TRPs of a transmitting sidelink UE. The message indicates a QCL assumption for the TRPs. The method also individually measures reference signals received from each transmission port of the TRPs. The method may also determine whether signaling from the TRPs satisfies all conditions for the QCL assumption, and report to the transmitting sidelink UE a result of the determining.

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: In various embodiments supporting directional security, a user equipment (UE) may receive from a network device a noise resource allocation including an indication of a noise direction and a noise parameter, generate a noise signal based at least in part on the noise parameter, and transmit the noise signal in the noise direction while transmitting a communication transmission signal in a different direction from the noise direction. In various embodiments, a network device may determine a geographic zone of interest, select one or more reconfigurable intelligent surfaces (RISs) associated with the geographic zone of interest, selecting one or more noise transmitting UEs, control the one or more noise transmitting UEs to transmit at least one noise signal, and control the one or more RISs to steer the at least one noise signal into the geographic zone of interest.

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 enhancing sidelink communications between devices. As described herein, a single sidelink control information (SCI) may schedule sidelink data transmissions with repetition in time and/or frequency.

Abstract: According to a first method, a first user equipment (UE) may receive sidelink control information (SCI) over a sidelink communication link between the first UE and a second UE. The SCI may indicate a precoding resource block group (PRG) size associated with sidelink communications with the second UE. The first UE may determine the PRG size for communications over the sidelink communication link based at least in part on the SCI. The first UE may then receive a sidelink message from the second UE via the sidelink communication link based on the determined PRG size, and may transmit a sidelink message to the second UE based on the determined PRG size.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may transmit, to a second UE, an initial transmission of a transport block via a sidelink unlicensed band. The UE may receive, from the second UE, a negative acknowledgement (NACK) based at least in part on the initial transmission of the transport block. The UE may transmit, to the second UE and based at least in part on the NACK and a retransmission reservation, a retransmission of the transport block via the sidelink unlicensed band in a retransmission occasion of a plurality of retransmission occasions associated with the retransmission reservation. Numerous other aspects are described.

Abstract: Certain aspects of the present disclosure provide a method for wireless communications between a first UE and a second UE. The method includes, at the first UE, receiving, from the second UE, a paging indication message on a sidelink channel, the paging indication message associating the first UE with one or more resources of a common resource pool that includes a plurality of resources for communication on the sidelink channel. The method further includes, based on the received paging indication message, monitoring the one or more resources for a message from the second UE.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may determine a communication collision between a first reservation, by a second UE, of a sidelink resource and a second reservation of the sidelink resource based at least in part on a first set of estimated reference signal received quality (RSRQ) values associated with the first reservation and a second set of estimated RSRQ values associated with the second reservation, wherein the first set of estimated RSRQ values corresponds to a plurality of transmitter-receiver points (TRPs) of the first UE, and wherein the second set of estimated RSRQ values corresponds to the plurality of TRPs. The UE may perform an action based at least in part on identifying the communication collision. Numerous other aspects are provided.

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: In some aspects of the disclosure, a method of wireless communication includes performing a first wireless transmission using a plurality of transmission and reception points (TRPs) of a vehicle. The first wireless transmission is performed based on a first transmit power allocation among the plurality of TRPs. The method further includes, in response to the first wireless transmission, receiving one or more feedback signals indicating a receive status of the first wireless transmission at one or more devices. The method further includes performing a second wireless transmission using the plurality of TRPs based on a second transmit power allocation among the plurality of TRPs. The second transmit power allocation is determined based on at least one received signal strength of the one or more feedback signals.

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 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.