Abstract: Methods, systems, and devices for wireless communication are described. One method for wireless communication at a first device includes receiving a multicast packet from a second device, decoding control header information in the received multicast packet, determining that a decoding procedure associated with a payload of the received multicast packet is unsuccessful and transmitting a negative acknowledgement (NACK) based at least in part on the determining. The method also includes retrieving a list of transmitter identifiers. In some cases, transmitting the NACK is based at least in part on the list of transmitter identifiers. The method further includes determining a transmitter identifier associated with the multicast packet and determining that the transmitter identifier is present in the list of transmitter identifiers.

Abstract: Certain aspects of the present disclosure provide techniques for mapping two-stage sidelink control with multiple layer sidelink data channel. A first user equipment (UE) can rate-match a multiple-layer second stage of a two-stage sidelink control information (SCI) transmission as a single layer. The first UE transmits the multiple-layer second stage of the two-stage SCI, to a second UE, using multiple antenna ports.

Abstract: Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to methods and apparatus for warning pedestrians, for example, of potential collisions with vehicles. The techniques may be considered a hybrid approach to reaching a pedestrian, in that it may employ a combination of interfaces (e.g., the radio interface between the pedestrian UE and the radio access network as well as a sidelink interface between the pedestrian UE and vehicle UE).

Abstract: Methods, systems, and devices for wireless communications are described that may enable a user equipment (UE) to transmit sidelink data within an interference avoidance resource scheduling scheme. For example, a UE may determine to segment a data packet for transmission in a vehicle-to-everything (V2x) system (e.g., to ensure that each segment fits within one transmission time interval (TTI)). In some cases, a UE may identify a data packet for transmission, may determine that the size of the data packet exceeds a threshold size, may segment the data packet to ensure each segment fits within one TTI, and may transmit the data packet segments (e.g., to additional UEs), where said transmissions may be discontinuous. In some examples, a UE may determine to segment the data packet and then encode the data packet. Additionally or alternatively, the UE may determine to encode the data packet and then segment the data packet.

Abstract: Disclosed are techniques for using ranging signals to determine a position of a pedestrian user equipment (P-UE). In an aspect, a UE receives a plurality of ranging signals transmitted by one or more UEs, measures one or more properties of each of the plurality of ranging signals, and calculates an estimate of the position of the P-UE based on the one or more properties of each of the plurality of ranging signals. In an aspect, the P-UE transmits a plurality of ranging signals, receives a first message and a second message from first and second vehicle UEs (V-UEs), the first and second messages including first and second estimated positions of the P-UE and associated first and second confidences, and calculates an estimate of the position of the P-UE based on the first estimated position, the first confidence, the second estimated position, the second confidence, or a combination thereof.

Abstract: In an aspect, the present disclosure includes a method, apparatus, and computer readable medium for wireless communications for receiving, by a relay user equipment (UE) from a remote UE, a remote UE radio resource control (RRC) message for establishing a relayed communication between the remote UE and a network entity via the relay UE; determining, by the relay UE, remote UE information associated with the remote UE for establishing a remote UE communication context between the relay UE and the network entity based on the remote UE RRC message; and transmitting, by the relay UE to the network entity, the remote UE RRC message and the remote UE information.

Abstract: Disclosed are techniques for wireless communication. In an aspect, a transmitter user equipment (UE) determines a first zone identifier (ID) corresponding to a first zone in which the transmitter UE is located, determines a distance threshold based on a distance requirement of an application associated with the transmitter UE, determines a second zone ID based on the first zone ID, the distance threshold, a size of the first zone, or any combination thereof, and transmits the second zone ID and the distance threshold to one or more receiver UEs. In an aspect, the receiver UE receives the second zone ID and the distance threshold, determines a distance between the receiver UE and the transmitter UE based on the second zone ID and a location of the receiver UE, and transmits, based on the distance being less than the distance threshold, a feedback message to the transmitter UE.

Abstract: Embodiments include systems and methods for sidelink communications. In embodiments, a processor of a wireless device may determine signal strength information and priority information associated with a sidelink communication resource. The processor may determine coordination information based on the determined signal strength information and priority information. The processor may generate a message to include the determined coordination information. The processor may transmit the generated message including the determined coordination information to a second wireless device. In some embodiments, the generated message may be a control message, such as a medium access control control-element (MAC-CE) or a sidelink control information message.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may utilize priority levels associated with packets or transmissions to determine whether to transmit feedback for a received transmission. The UE may compare priority levels between a transmission subject to a feedback condition and a transmission scheduled to be received when the feedback is scheduled to be transmitted to determine whether to send the feedback. The UE may communicate with the transmitting device according to the comparison and the determining. The UE may determine signal conditions causing a NAK and determine to send the NAK based on the signal conditions.

Abstract: Aspects of the present disclosure describe indicating per-packet quality of service (QoS) in communications by a wireless communications device. A packet from an application generated for a first radio access technology (RAT) can be obtained, where the packet includes a first QoS value associated with the first RAT, and/or the first QoS value can be mapped to a second QoS value associated with the second RAT. In another example, the QoS value can be indicated in the packet along with a reflective indicator indicating to use the QoS value in transmitting a response to the packet.

Abstract: Methods, systems, and devices for sidelink wireless communications are described in which a user equipment (UE) engaged in sidelink communications may provide for radio link maintenance of the sidelink connection by initiating a maintenance procedure, such as a measurement procedure, when one or more conditions are detected. The one or more conditions may include a threshold time being exceeded since a data transmission via the sidelink connection, or a threshold time being exceeded since a successful reception of a sidelink transmission from another UE. An access stratum layer at the initiating UE may format a data packet in the absence of higher layer data to be transmitted via the sidelink connection to initiate the maintenance procedure.

Abstract: Aspects relate to mechanisms for a wireless communication device to generate a superposition transmission of a sidelink signal to be transmitted to at least one receiving wireless communication device and an uplink signal to be transmitted to a base station. The wireless communication device may transmit the superposition transmission on resources allocated by the base station on a common carrier utilized for both sidelink and uplink transmissions. The superposition transmission includes a base layer corresponding to the uplink signal and an enhanced layer corresponding to the sidelink signal. The wireless communication device may further generate and transmit interference assistance information to the receiving wireless communication device for use by the receiving wireless communication device in canceling the base layer from the superposition transmission.

Abstract: Disclosed are techniques for wireless communication. In an aspect, a transmitter user equipment (UE) determines a first demodulation reference signal (DMRS) pattern for a first slot allocated for transmission over a sidelink between the transmitter UE and a receiver UE, wherein the first DMRS pattern is determined based at least on the first slot having a first slot format of two or more slot formats, and transmits, to the receiver UE, DMRS in the first slot according to the first DMRS pattern. In an aspect, the receiver UE determines the first DMRS pattern for the first slot based at least on the first slot having the first slot format, and receives, from the transmitter UE, DMRS in the first slot according to the first DMRS pattern.

Abstract: Methods, systems, and devices for wireless communications are described. A communication device supports sidelink communications, including device-to-device (D2D) communications and vehicle-based communications. The communication device receives, from another device, a discontinuous transmission (DTX) configuration for a sidelink connection between the communications device and the other device. Based on the received DTX configuration, the communications device determines a discontinuous reception (DRX) configuration and transmit, to the other device, the determined DRX configuration. The devices experience power savings, among other results according to the DTX configuration or the DRX configuration.

Abstract: Aspects relate to managing a device-to-device communication link via radio resource control (RRC) layer signaling. In an example operation, a first wireless communication device establishes a unicast link with a second wireless communication device over a device-to-device communication interface and determines that the unicast link is to be reconfigured with at least one updated parameter. The first wireless communication device then sends a link reconfiguration request to the second wireless communication device via a first RRC message over the communication interface. The first RRC message includes the at least one updated parameter. The first wireless communication device receives a link reconfiguration response from the second wireless communication device via a second RRC message over the communication interface based on the link reconfiguration request and determines whether to reconfigure the unicast link using the at least one updated parameter based on the received link reconfiguration response.

Abstract: Methods, systems, and devices for wireless communications are described. A communication device, which may be otherwise known as user equipment (UE), may identify a default modulation and coding scheme table and a preconfigured modulation and coding scheme table associated with a resource pool. The UE may receive, from a transmitting communication device, an indication of the preconfigured modulation and coding scheme table to use for upcoming sidelink communications. The UE may then communicate based on the preconfigured modulation and coding scheme table.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may perform at least one transmission of a communication, wherein the at least one transmission includes information indicating a feedback parameter for feedback regarding the at least one transmission, wherein the feedback parameter is a function of a control exclusion parameter of the UE. The UE may retransmit the communication when the feedback indicates that the at least one transmission was not received by a recipient device within the feedback parameter. 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, from a base station, a slot configuration identifying one or more symbols to be used for sidelink communications. The user equipment may transmit an indication of the slot configuration to another user equipment to configure the other user equipment to use the identified one or more symbols for sidelink communications. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described, in which a user equipment (UE) may communicate with one or more other UEs using sidelink communications. Multiple UEs may form a sidelink communications group and provide for sidelink groupcast communications in which an identification of a UE is determined based at least in part on a member identification of the UE within the group. Each UE in the group may determine feedback resources for acknowledgment feedback within the group based on a UE identification and a size of the group.

Abstract: Certain aspects of the present disclosure are generally directed to techniques for selecting a configuration for communication using vehicle to everything (V2X) type communication protocol. Certain aspects provide a method for wireless communication by a user-equipment (UE). The method generally includes determining one or more parameters corresponding to quality of service (QoS) information for communication of data using a V2X communication protocol, reporting the one or more parameters by transmitting a first message, receiving a second message indicating configuration information corresponding to the communication of the data using the V2X communication protocol, and communication the data based on the configuration information.