Abstract: Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may transmit the sidelink message to a second UE via a sidelink communications channel of an unlicensed radio frequency spectrum band. The first UE or the second UE may transmit a reservation signal to retain the sidelink communication channel for corresponding feedback for the sidelink message (e.g., while the second UE generates a feedback transmission). The second UE may transmit the feedback transmission over the sidelink communication channel.

Abstract: Methods, systems, and devices for wireless communications are described. A transmitting user equipment (UE) such as a vehicle may identify data for transmission and transmit a request message to one or more receiving UEs (e.g., other vehicles). The request message may be associated with a first priority. The transmitting UE may monitor resources for a response message. The response message may be associated with a second priority. If the transmitting UE receives a response message, the transmitting UE may determine whether to transmit the data based on a comparison of the priorities of the request message and the response message. In some cases, the transmitting UE may transmit the data if the transmitting UE does not receive any response message. A receiving UE may receive the request message and determine whether to transmit a response message based on the priority and/or the receive power of the request message.

Abstract: Methods, systems, and devices for wireless communication are described to support security techniques for ranging in wireless networks. A first device may transmit an indication to initiate a ranging procedure with a second device, and in response to the indication, the second device may transmit signaling to the first device and to one or more third devices. The first device and the one or more third devices may each determine a respective location metric associated with the second device based on the signaling. The one or more third devices may each transmit, to the first device, the respective location metric. Based on the communicated location metric(s), the first device may determine whether an eavesdropper is present and may communicate with the second device based on the determination.

Abstract: Techniques are provided which may be implemented using various methods and/or apparatuses in a vehicle to utilize vehicle external sensor data, vehicle internal sensor data, vehicle capabilities and external CV2X input to determine, send, receive and utilize data elements to determine inter-vehicle spacing, intersection priority, lane change behavior and spacing and other autonomous vehicle behavior.

Abstract: An apparatus receives, in a transmission from a second UE, an indication of reserved resources for the second UE. The apparatus measures a received power of the transmission from the second UE. The apparatus excludes the reserved resources indicated by the second UE from a set of candidate resources based on the received power of the transmission from the second UE meeting a threshold, where the threshold is based at least in part on whether the reserved resources are associated with a retransmission.

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 via reflection by one or more passive devices, a first reference signal (RS) that is based at least in part on a shared first key that corresponds to a configuration of the one or more passive devices. The first UE may receive, from the second UE via reflection, a second RS that is based at least in part on the first key. The first UE may generate a second key based at least in part on a measurement of the second RS. The first UE may transmit a positioning reference signal that is based at least in part on the second key and that is associated with a measurement of a range between the first UE and the second UE. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine, periodically, at least one metric associated with a current reference signal on a sidelink. Accordingly, the UE may extend a time window allowed for a search for a new reference signal on the sidelink based at least in part on the at least one metric. For example, the UE may extend the time window as a function of a discontinuous reception cycle associated with the UE. Alternatively, the UE may extend the time window for a preconfigured amount of time. Numerous other aspects are described.

Abstract: Improved communications, including indication of channel occupancy time-structure information (COT-SI) for NR-U sidelink (NR-U SL) operations is disclosed. A UE may establish a current channel occupancy time (COT) on a shared communication spectrum for UE transmissions in response to a successful listen before talk (LBT) procedure. The UE may then generates a COT structure information (COT-SI) message including at least a remaining duration of the current COT and a set of time and frequency resources of the current COT. The COT-SI message may be transmitted by the UE to one or more neighboring UEs via sidelink transmission. Once the COT-SI message is sent, the UE transmits the UE transmission within the set of time and frequency resource of the current COT.

Abstract: Certain aspects of the present disclosure provide methods and apparatus for determining a Zone identifier (ID), Zone Center, and negative acknowledgement (NACK) ranges. Included are operations and means at a receiving user equipment (UE) to determine a current geographic location (GLL) of the receiving UE, and select a Zone ID based on a two-dimensional (2-D) lookup into an indexed array with the current GLL, the indexed array storing Zone data for one or more geographic Zones. The Zone data for each geographic Zone may be indexed according to geographic position, and include a Zone ID, Zone center, and one or more NACK ranges, each NACK range corresponding with a geographic Zone disposed about the geographic Zone corresponding to the Zone ID. Operations further include performing a NACK operation based on the selected Zone ID and a NACK range.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a packet at a transmitter of the UE for transmission in a sidelink network. The UE may select one or more resources for transmission of the packet based at least in part on a reservation status of the one or more resources, wherein at least one of the one or more resources is a reserved resource that is reserved by another UE. The UE may transmit the packet using the one or more resources based at least in part on selecting the one or more resources. Numerous other aspects are provided.

Abstract: This disclosure provides systems, methods, and devices for wireless communication that support vehicle alerting, such as in autonomous driving networks. Vehicle alerting may provide messages alerting other vehicles and/or network components to instances of autonomous driving disengagement. A vehicle operating according to an autonomous vehicle (AV) mode may transmit an over-the-air message to one or more other devices, such as nodes of an autonomous driving network, to alert the one or more devices to the vehicle disengaging the AV mode. A device receiving an autonomous disengagement message may alter one or more autonomous operation aspects in response to the over-the-air message. 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 first user equipment (UE) may receive, from a base station or a roadside unit (RSU), information associated with one or more security keys for sidelink communications, wherein the information includes at least one of a base key, the one or more security keys, or one or more parameters for deriving the one or more security keys. The UE may transmit, to a second UE, a sidelink communication that is scrambled using a security key of the one or more security keys. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a vulnerable road unit (VRU) device may determine that a parameter associated with movement of the VRU device satisfies one or more thresholds indicated in an event reporting configuration. The VRU device may transmit, to a vehicle user equipment device, an indication of an event associated with the VRU device based at least in part on determining that the parameter satisfies the one or more thresholds. Numerous other aspects are provided.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The apparatus may receive from a second device a first data packet in one or more receiving slots of a time division duplex frame that includes a plurality of slots. The apparatus may determine whether the first data packet is received incorrectly. The apparatus may wait until the end of the one or more receiving slots and may transmit to the second device a first NACK in a NACK feedback symbol in a configured slot after the end of the one or more receiving slots in response to determining that the first data packet was not received correctly.

Abstract: Aspects of the present disclosure include methods, apparatuses, and computer readable media for receiving a plurality of requests, from a plurality of user equipments (UEs), to exit a parking area comprising a plurality of vehicles, wherein each of the plurality of UEs is associated with a corresponding vehicle of the plurality of vehicles, determining an exit order for the plurality of vehicles to exit the parking area, and transmitting, to the plurality of UEs, a plurality of exit commands, based on the exit order, for the plurality of vehicles to exit the parking area.

Abstract: To facilitate coexistence of a first radio access technology (RAT) and a second RAT, methods, apparatuses, and computer program products are provided. An example method of a first wireless device operating based on a RAT includes receiving a sidelink resource reservation from a second wireless device based on a second RAT, the sidelink resource reservation indicating a first set of resources. The example method further includes determining whether to exclude, from a candidate resource set for the first RAT within a sidelink resource pool for the first RAT, resources that overlap with the set of reserved resources for the second RAT. The example method further includes transmitting a sidelink transmission using one or more sidelink transmission resources selected from the candidate resource set in the sidelink resource pool for the first RAT.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to select, from a resource pool for sidelink communications, a set of resources for one or more sidelink messages to be performed by the UE. The UE may select an additional resource to transmit a resource reservation for an earliest resource of the set of resources, the selection of the additional resource based on a time interval between the additional resource and the earliest resource satisfying a time threshold. The UE may transmit, via the additional resource, An inter-UE (IUE) coordination message including an indication of the earliest resource within a first-stage sidelink control information portion of the IUE coordination message, and may transmit a first sidelink message of the one or more sidelink messages within the earliest resource indicated via the first-stage sidelink control information portion of the IUE coordination message.

Abstract: Aspects described herein relate to receiving, over a sub-channel of multiple sub-channels, ultra-reliable quality-of-service (QoS) traffic from one or more UEs over a time duration wherein other sub-channels of the multiple sub-channels are used for initial ultra-reliable QoS transmissions from one or more other transmitting UEs over the time duration, and relaying, along with one or more other relaying UEs, the ultra-reliable QoS traffic over a subsequent time duration.

Abstract: Techniques are provided which may be implemented using various methods and/or apparatuses in a vehicle to utilize vehicle external sensor data, vehicle internal sensor data, vehicle capabilities and external CV2X input to determine, send, receive and utilize data elements to determine inter-vehicle spacing, intersection priority, lane change behavior and spacing and other autonomous vehicle behavior.

Abstract: Methods, systems, and devices for wireless communications (e.g., vehicle to everything systems) are described relating to an adaptive design of demodulation reference signals (DMRS) density based on user equipment (UE) velocity. A UE may send assistance information to a transmitting UE to help identify a DMRS pattern based on the relative speed between the two UEs. Also, the transmitter may determine the adaptive DMRS pattern based on its speed without information of the receiver's speed. The transmitter may indicate the adaptive DMRS pattern in control information to the receiver. A base station may receive assistance information, and the base station may determine the adaptive DMRS pattern to be used by the transmitting UE based on the received assistance information and then indicate the adaptive DMRS pattern to the transmitting UE. A UE may determine an adaptive DMRS pattern to use based on feedback from the receiving UE.