Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit a first message identifying a set of UEs comprising one or more other UEs with which the UE is engaging in sidelink communication. The UE may transmit a second message, based at least in part on a determination of a loss of a sidelink connection to a previously-connected UE of the set of UEs, identifying a subset of the set of UEs and indicating the loss of the sidelink connection. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A receiver user equipment (UE) may communicate with a transmitter UE in a sidelink channel to report a congestion index to the transmitter UE and/or additional transmitter UEs, where the transmitter UE(s) may then adjust one or more sidelink operation parameters based on the reported congestion index. In some cases, the transmitter UE may report the congestion index to an upper layer, to other transmitter UEs, to application layers, or a combination thereof. The transmitter UEs 115 and/or application layer may then adjust one or more sidelink transmission operation parameters based on the reported congestion index. For example, the transmitter UEs and/or application layer may adjust threshold values to lessen a number of retransmissions and lessen congestion.

Abstract: Certain aspects of the present disclosure provide techniques for sidelink feedback in resource pool. A first user equipment (UE) can determine a slot, from a resource pool including a plurality of slots allocated for sidelink communications, for providing hybrid automatic repeat request (HARQ) feedback to a second UE via a sidelink channel. The determination may be based on a physical slot index or a logical slot index. The first UE may send the HARQ feedback on the sidelink channel in the slot, or refrain from sending the HARQ feedback, based on the determination.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit, to a second user equipment, an indication of a time buffer threshold associated with providing sidelink hybrid automatic repeat request feedback on a physical sidelink feedback channel. The UE may receive, from the second user equipment, an indication of an agreement to use the time buffer threshold. The UE may transmit, to the second user equipment and based at least in part on the indication of the agreement, sidelink hybrid automatic repeat request feedback for a sidelink communication received from the second user equipment, the sidelink hybrid automatic repeat request feedback being transmitted on the physical sidelink feedback channel based at least in part on the time buffer threshold. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A communication device, which may be otherwise known as user equipment (UE), may receive a data transmission and determine a slot to transmit a hybrid automatic repeat request (HARQ) feedback based on the data transmission. The communication device may determine one or more HARQ feedback resources or one or more HARQ feedback resource sets in the slot to transmit the HARQ feedback, where the one or more hybrid automatic repeat request feedback resources or the one or more hybrid automatic repeat request feedback resource sets in the slot comprises a set of frequency resources associated with the slot, and transmit the HARQ feedback using the one or more HARQ feedback resources or the one or more HARQ feedback resource sets in the slot.

Abstract: Certain aspects of the present disclosure provide techniques for flexible resource reservations in sidelink communications. An example method that may be executed by a first user equipment (UE) includes determining, for sidelink communications with a second UE, one or more first resource reservations and one or more second resource reservations. The second resource reservations may have a different frequency resource allocation than the first resource reservations. The method also includes transmitting, to the second UE, control information having an indication of the first resource reservations and the second resource reservations. The method further includes communicating with the second UE based on the first resource reservations and the second resource reservations.

Abstract: Certain aspects of the present disclosure provide techniques for managing resource reservations in sidelink communications. A method that may be performed by a first user equipment (UE) includes determining a plurality of resource reservations allocated for sidelink communications with at least one second UE and transmitting, to the at least one second UE, control information having an indication of the resource reservations. The method also includes communicating with the at least one second UE during at least one of the resource reservations and determining that a remaining set of the resource reservations is enabled to be reclaimed by one or more UEs. The method further includes taking one or more actions based on the determination that the remaining set of the resource reservations is enabled to be reclaimed by the one or more UEs.

Abstract: Methods, systems, and devices for wireless communications are described. A communication device, which may be otherwise known as user equipment (UE), may receive a data transmission and determine a feedback timing value based on the data transmission. The communication device may determine a feedback resource set in a resource pool associated with one or more slots based on the feedback timing value, and transmit a feedback using the feedback resource set associated with the one or more slots and corresponding to the feedback timing value.

Abstract: Disclosed are techniques for transmitting and receiving a plurality of encoded information bits on a radar signal. In an aspect, a transmitter radar generates a first set of modulated phase-coded symbols to convey the plurality of encoded information bits, generates a second set of modulated phase-coded symbols as reference symbols having a known phase modulation, phase codes a plurality of chirps of the radar signal according to the first and second sets of modulated phase-coded symbols, and transmits the plurality of chirps according to the phase coding. A receiver radar determines a phase difference between the receiver and transmitter radars based on a phase of the plurality of chirps, equalizes the phase based on the determined phase difference, determines a phase code of the first set of symbols based on the equalized phase, and decodes the encoded information bits based on the phase code of the first set of symbols.

Abstract: Wireless communications systems and methods related to sidelink communications in a TDD system are provided. A first user equipment (UE) may receive from a base station (BS), a time-division-duplexing (TDD) configuration. The first UE may select a first TDD configuration from a set of configured TDD configurations based on the TDD configuration. Additionally, the first UE may transmit to a second UE, an indication of the first TDD configuration. The first and the second UEs may communicate a sidelink communication based on the first TDD configuration. Other features are also claimed and described.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may perform a slot reservation procedure to obtain a TxOP for communicating with a second UE. The slot reservation procedure may be performed in an earliest slot in the TxOP in which the first UE has data to send to the second UE. The apparatus may transmit the data to the second UE using at least one slot in the TxOP when the slot reservation procedure is successful. In certain aspects, all remaining slots in the TxOP may be reserved for the first UE when the slot reservation procedure is successful. The apparatus may refrain from performing a subsequent slot reservation procedure in another slot in the TxOP when the slot reservation procedure is unsuccessful unless an end of transmission signal is received during the TxOP.

Abstract: Certain aspects of the present disclosure provide techniques for floating-band channel state information (CSI) reference signals (RS). A method that may be performed by an apparatus includes determining a floating band for transmitting one or more CSI-RSs to a wireless device based on a previously scheduled data transmission by the apparatus. The apparatus transmits the one or more CSI-RSs to the wireless device on the floating band. In some aspects, a wireless device receives, from an apparatus, one or more floating-band CSI-RSs. The wireless device generates one or more CSI reports based on the one or more CSI-RSs and transmits the one or more CSI reports.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may configure a first set of resources for a physical sidelink shared channel (PSSCH) transmission. The UE may configure a second set of resources for a sidelink channel state information (CSI) reference signal (CSI-RS) transmission, the sidelink CSI-RS transmission is associated with the PSSCH transmission, and the sidelink CSI-RS transmission occurs prior to the PSSCH transmission. The UE may transmit a first sidelink control information (SCI) in a physical sidelink control channel (PSCCH) transmission, the first SCI including an indication of the first set of resources and the second set of resources. Numerous other aspects are provided.

Abstract: Certain aspects of the present disclosure provide techniques for sidelink communication. A method that may be performed by a user equipment (UE) includes selecting a modulating and coding scheme (MCS) and a transmission power based on a configured dependency between one or more candidate MCSs and one or more candidate transmission powers, and transmitting, via a sidelink channel, one or more frames using the selected MCS and the selected transmission power.

Abstract: Aspects of the present disclosure provide techniques for configuring device-to-device (D2D) communication in new radio (NR) for one or more user equipments (UEs). Specifically, features of the present disclosure provide techniques for initial beam-pairing for sidelink communication that optimize communication resources (e.g., resource pools) by indicating the direction of traffic (e.g., transmit or receive) during the initial beam-pairing procedure and to establish sidelink communication without the need for scheduling request transmissions between the UEs.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a sidelink channel state information (CSI) reference signal (CSI-RS). The UE may transmit, based at least in part on the sidelink CSI-RS, a CSI report on a physical sidelink feedback channel. Numerous other aspects are provided.

Abstract: Methods, systems, and devices are described for vehicle-to-everything (V2X) communication over one or more determined transmission time intervals (TTIs) in an unlicensed (shared) radio frequency spectrum band. A user equipment (UE) such as a vehicle may perform one or more listen-before-talk (LBT) mechanisms on the shared radio frequency spectrum and contend for access to available system resources. Upon gaining access, the UE may determine a data payload for transmission. The data type or payload may exceed a threshold and as a result, the UE may bundle a multiple TTIs for continuous data transmission. The UE may send control information, indicating a TTI bundling implementation as well as modification to the control or LBT symbols of subsequent TTIs of the data transmission, and subsequently perform data transmission over a plurality of TTIs.

Abstract: Some aspects provide a method for wireless communication by a first wireless device. The method generally includes receiving one or more instances of channel state information reference signals (CSI-RS), generating CSI based on one or more of the CSI-RS instances, determining timing for transmitting the CSI based, at least in part, on at least one condition involving the CSI-RS instances, and transmitting the CSI in accordance with the determined timing.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit to a base station a request for resources including an indication of a transmission beam for performing a sidelink communication in a millimeter wave (mmW) system. The base station may determine a transmission configuration based on the request for resources. The UE may transmit reference signals based on the transmission configuration, and the base station may monitor for the reference signals using one or more reception beams. The base station may determine timing information for the sidelink communication, and transmit the timing information to the UE in a resource grant. Based on the timing information, the UE may perform the sidelink communication using the transmission beam. In some examples, the sidelink communication may be multiplexed in frequency from the perspective of the base station with an uplink transmission from another UE.

Abstract: Some aspects provide a method for wireless communication by a first wireless device. The method generally includes transmitting control information regarding at least one of scheduling or configuration of a channel state information (CSI) report to be transmitted by the first wireless device. The method generally includes generating the CSI report based on one or more CSI reference signals (CSI-RSs) received by the first wireless device. The method generally includes and transmitting the CSI report in accordance with the control information.