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: 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: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a sidelink transmission that includes a transport block, and may transmit sidelink feedback, for each of a plurality of code block groups included in the transport block, in respective physical sidelink feedback channel (PSFCH) resources. In some aspects, a UE may receive a sidelink transmission that spans a plurality of slots, and may transmitting, for the sidelink transmission, sidelink feedback in at least one of: first one or more PSFCH resources that occur during the sidelink transmission, or second one or more PSFCH resources that occur after the sidelink transmission. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communication are described. A transmitting device may select an orthogonal metric based at least in part on at least one of each direction of a plurality of directions to transmit millimeter wave discovery signals or a location parameter associated with the transmitting device. The transmitting device may transmit, in the each direction of the plurality of directions, the millimeter wave discovery signals, where the each transmitted millimeter wave discovery signal has a different orthogonal metric applied that was selected based at least in part on the at least one of the each direction or the location parameter.

Abstract: Methods, apparatuses, and computer-readable mediums for wireless communication by a user equipment (UE) includes transmitting a packet on a first resource, determining one or more repetition resources on which to send one or more redundancy versions of the packet, wherein the one or more repetition resources are at a time subsequent to the first resource, transmitting repetition resource information identifying the one or more repetition resources to one or more neighboring UEs, and transmitting the one or more redundancy versions of the packet on respective ones of the one or more repetition resources.

Abstract: Aspects described herein relate to determining a congestion level related to communicating with one or more devices in a wireless network, determining, based on the congestion level, a retransmission scheme for transmitting and/or retransmitting communications in the wireless network, and transmitting or retransmitting a communication in the wireless network based on the retransmission scheme.

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: Certain aspects of the present disclosure provide techniques for channel estimation for two-stage sidelink control using sidelink data channel demodulation reference signals (DMRS). A user equipment (UE) can transmit DMRS for the sidelink data channel. The UE may transmit the second stage of the sidelink control using antenna ports or a precoder used for the sidelink data channel. The receiving device may receive the DMRS, estimate the channel, and demodulate the second stage of the sidelink control based on the estimated channel. The receiving device may flexibly determine the DMRS to use for the estimation and demodulation.

Abstract: Methods, systems, and devices for wireless communications are described. Generally, the described techniques at a user equipment (UE) provide for efficiently falling back to a half-duplex mode from a full-duplex mode when a level of interference is high. In particular, the UE may measure the level of interference at the UE (e.g., caused at least partially by self-interference between transmissions and receptions at the UE), and the UE may fall back to a half-duplex mode if the level of interference is above a threshold. In one example, the UE may transmit channel state information (CSI) reference signals (CSI-RSs) on resources allocated for interference measurements, and the UE may perform measurements on the CSI-RSs to identify a level of interference. In another example, the UE ay transmit a data packet on resources allocated for interference measurements, and the UE may decode the data packet to identify a level of interference.

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: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine, for a device-to-device communication with another UE, a modulation and coding scheme (MCS) configuration, of a set of MCS configurations, based at least in part on at least one of a transmission mode, a packet characteristic, a mobility state of the UE, a capability of the UE, a transmission mode of the device-to-device communication, a received indication from the other UE, or a combination thereof. The UE may transmit, to the other UE, data using an MCS selected based at least in part on the MCS configuration. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE), may receive, at a processing layer of the UE, sets of discontinuous reception (DRX) cycle parameters from a corresponding set of applications at an application layer of the UE. The UE may determine, based on the sets of DRX parameters, a common DRX cycle to satisfy each of the sets of applications. The UE may transmit the common DRX cycle to one or more layers in the user plane protocol stack of the UE. A base station may also receive a request, from the UE, for a set of DRX cycle parameters that satisfies the common DRX cycle of the UE. The base station may transmit an indication of the set of DRX parameters, and receive, from the UE, a confirmation of a DRX cycle associated with the set of DRX cycle parameters.

Abstract: This disclosure provides systems, methods and apparatus, including computer storage media, for retransmission of sidelink transmissions using network coding with binned feedback. A transmitting device transmits a transport block and a request for a network coding (NC) encoding device to retransmit the transport block to a plurality of user equipment (UEs). The UEs decode the transport block and report an acknowledgment (ACK) or negative acknowledgment (NACK) on a physical sidelink feedback channel (PSFCH) resource associated with a bin for the UEs. The NC encoding device decodes the PSFCH resource for each bin to determine an ACK or NACK status for each bin, and determines whether to encode the transport block in a NC combination packet. The UEs receive the NC combination packet including an encoding of a subset of transport blocks. The receiving devices transmit an ACK or NACK on a PSFCH resource for a bin for each transport block.

Abstract: Certain aspects of the present disclosure provide techniques for recovering a sidelink communication. A wireless node may receive a plurality of sidelink communications, each sidelink communication between two user equipments (UEs); and transmit recovery information in a recovery slot, wherein the recovery information is for recovery of at least one of the sidelink communications by the two UEs or other UEs that transmitted when at least one of the sidelink communications occurred and wherein the recovery slot is for transmission of the recovery information.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first wireless communication device may receive, on a sidelink and from a second wireless communication device, resource reservation information associated with the second wireless communication device. The resource reservation information may identify sidelink resources that are reserved for the second wireless communication device for transmission on the sidelink. The first wireless communication device may transmit, on the sidelink, the resource reservation information to a third wireless communication device. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) to be scheduled by a scheduler UE in a sidelink system may transmit a first scheduling request (SR) to request sidelink resources. The UE may transmit the first SR via a set of feedback resources. The scheduler UE may transmit, to the UE, a sidelink control message to schedule a sidelink transmission. The sidelink control message may indicate a set of feedback resources mapped to the sidelink transmission. The UE may transmit the scheduled sidelink transmission based on the sidelink control message and may request additional sidelink resources. The UE may transmit a second SR, where the second SR is transmitted via the set of feedback resources mapped to the sidelink transmission.

Abstract: Certain aspects of the present disclosure provide techniques for high reliability vehicle-to-everything (V2X) communications. Aspects of the present disclosure provide methods that may be performed by a first sidelink device. The first sidelink device may be a roadside unit (RSU) or a user equipment (UE). The first sidelink device may detect traffic from at least a second sidelink device and send the traffic to one or more other sidelink devices. A first sidelink device may receive reservation information from a first plurality of sidelink devices and schedule a second plurality of sidelink devices based on the reservation information.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment may determine parameters for congestion metrics based on a type for a channel access procedure associated with a sidelink transmission. The user equipment may determine a channel access procedure type for a sidelink channel transmission, and determine a limit for a channel occupancy (e.g., a channel occupancy ratio) based on the type. The user equipment may compare the channel occupancy with the limit to determine whether to transmit the sidelink channel transmission, based on whether the channel is available. In some aspects, the user equipment may additionally perform the channel access procedure (e.g., a listen before talk procedure) to determine whether to transmit the sidelink channel transmission. The user equipment may also perform channel measurements to obtain a congestion metric (e.g., a channel busy ratio) based on a threshold before transmitting the sidelink channel transmission.

Abstract: A transmitting user equipment (UE) may perform resource hopping for a periodic sidelink resource reservation by scheduling a plurality of periodic sidelink resources with a first periodicity, the plurality of periodic sidelink resources being shifted at a first offset in a frequency domain. The transmitting UE may reduce persistent collisions of periodic or semi-persistent scheduling (SPS) reservation of the sidelink resources with another UE. The transmitting UE may transmit, to a receiving UE, sidelink control information (SCI) indicating the first offset and the plurality of sidelink transmissions via the plurality of periodic sidelink resources at the first periodicity based on the SCI. The receiving UE may receive, from the transmitting UE, the SCI and the plurality of sidelink transmissions via the plurality of periodic sidelink resources at the first periodicity based on the SCI.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a mobile station may transmit, from the mobile station to an encoding device, acknowledgement or negative acknowledgement (ACK-NACK) feedback based at least in part on a transmission by the encoding device, wherein the ACK-NACK feedback is associated with a feedback bin, and wherein the feedback bin is associated with a location of the mobile station. The mobile station may receive, at the mobile station from the encoding device, a network coding transport block, wherein the network coding transport block is formed based at least in part on the transmission and the ACK-NACK feedback associated with the feedback bin. Numerous other aspects are described.