Abstract: Aspects relate to techniques for efficient sidelink resource reservation based on the congestion on a sidelink. A wireless communication device may transmit control information indicating a number of resources reserved for an initial transmission and at least one retransmission of a packet. In some examples, the number of resources included in the control information can be either three resources or two resources based on the congestion. For example, the number of resources included in the control information can be three resources in response to a congestion value representing the congestion on the sidelink being less than a threshold. In addition, the number of resources included in the control information can be two resources in response to the congestion value being greater than or equal to the threshold.

Abstract: Certain aspects of the present disclosure provide techniques for sidelink communications. A method that may be performed by a user equipment (UE) includes monitoring a latency between a packet arrival time from an upper layer at the UE and an over-the-air (OTA) packet transmission time. The latency is based at least in part on, a first number of subframes reserved for a sidelink synchronization signal (SLSS) and/or a second number of subframes reserved based on a configured subframe bitmap. The method includes triggering a transmit resource selection at the UE when the latency exceeds a threshold latency.

Abstract: Methods and systems for performing time synchronization for a Cellular Vehicle-to-Everything (C-V2X) wireless interface of a vehicle are provided. In one example, a method comprises: determining, by a vehicle UE, whether a Global Navigation Satellite System (GNSS) receiver of the vehicle receives a GNSS signal including time information for a time synchronization operation for the vehicle's local clock source; based on whether the GNSS receiver receives a GNSS signal including the time information, adjusting a local clock time of the vehicle's local clock source based on one of: the time information included in the GNSS signal, or one or more wireless signals broadcasted from a base station; and adjusting, based on the adjusted local clock time, at least one of: a phase or a frequency of a clock signal supplied to the C-V2X wireless interface.

Abstract: Methods, systems, and devices for wireless communications are described. Generally, the user equipment (UE) may adjust an operational mode of a circuit of the UE by selecting one or more parameters (e.g., power level or clock frequency or both). Adjusting parameter values may result in avoiding increased temperature. The UE may set an operational mode of a circuit based on a determination or a prediction of a number of blind decodes to be performed, a number of pending receive packets, or a number of transmitting UEs from which the UE will receive traffic. The UE may efficiently reduce unnecessary power expenditures and decrease temperature.

Abstract: Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for synchronizing a UE's timing for sidelink communications with one or more other UEs. The techniques may be used, for example, in NR V2X systems to maintain sidelink timing synchronization when a UE is outside the coverage area of a synchronization source such as a global navigation satellite system (GNSS).

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a transmitter device may determine that a criterion relating to semi-persistent scheduling (SPS) is satisfied, wherein the criterion relates to packet arrival times for SPS transmission; and trigger an SPS resource reselection based at least in part on determining that the criterion is satisfied. Numerous other aspects are provided.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive an indication that identifies one or more neighbor cells, of a set of neighbor cells, that support a service; and perform a cell reselection process based at least in part on the indication that the one or more neighbor cells support the service. Numerous other aspects are provided.

Abstract: Certain aspects of the present disclosure provide techniques for collision mitigation in sidelink. A method that may be performed by a user equipment (UE) includes measuring channel busy ratio (CBR), estimating a number of UEs using the channel, estimating a congestion level based on the CBR and the estimated number of UEs. A method that may be performed by a sidelink UE includes determining a semi-persistent scheduling (SPS) resource reservation including first subframes, determining second subframes for generated packet transmission, determining to skip transmission in the second subframes, listening during the second subframes for another sidelink UE’s transmission, and determining whether to reselect resources. Another method includes listening during a first subframe for another sidelink UE’s transmission, detecting the transmission collides with a scheduled transmission resource for the sidelink UE based on an amount of frequency resource overlap, and determining to reselect resources.