Abstract: Methods, systems, and devices for wireless communications are described. A base station may be co-located with a sidelink wireless device, such as a road-side unit (RSU). The base station may determine that a cellular user equipment (C-UE) and a vehicle UE (V-UE) are co-located, and altering downlink communications to the C-UE. The RSU may communicate over sidelink with a V-UE, and determine positioning information of a V-UE. The base station may communicate with a C-UE using downlink and uplink communications (e.g., Uu communications), and may determine some positioning information of a C-UE. The base station and RSU may communicate the positioning information of each device, and the base station may determine that the C-UE and V-UE are co-located. The base station may alter a feedback configuration for the C-UE based on the co-location determination.

Abstract: Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may establish a unicast connection over a sidelink communications with a second UE. To establish the unicast connection over the sidelink, the first UE may transmit a request message (e.g., a first message) to the second UE, and the second UE may transmit a response message (e.g., a second message) to the first UE accepting the request. The unicast connection over the sidelink may then be established between the first UE and the second UE, and user data may then be transmitted over the sidelink on the established unicast connection. Additionally, the first UE may transmit a connection complete message (e.g., a third message) to the second UE indicating that the unicast connection has been established. The request message, the response message, and the connection complete message may be radio resource control (RRC) messages.

Abstract: Method and apparatus for a prioritization of synchronization signals for NR-LTE in-band coexistence. The apparatus detects a first sidelink synchronization signal from a first RAT and a second sidelink synchronization signal from a second RAT. The apparatus determines a priority between a synchronization source associated with the first RAT and the second RAT. The apparatus transmits data using a timing based on a determination of the priority between the first RAT and the second RAT. The apparatus determines to transmit a sidelink synchronization signal to be the synchronization source in response to detecting the first sidelink synchronization signal from the first RAT. The apparatus determines to transmit at least one of the first sidelink synchronization signal or the second sidelink synchronization signal.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive an indication of a time offset for synchronization signal resources for synchronization signals associated with a first radio access technology (RAT). The UE may determine the synchronization signal resources and a synchronization periodicity based on the indication and a penetration ratio of UEs associated with the first RAT. The UE may selectively transmit the synchronization signals on the synchronization signal resources and according to the synchronization periodicity. Additionally, or alternatively, the UE may determine that other synchronization signal resources are allocated for a second RAT and may select resources for communications associated with the first RAT based on determining that the other synchronization signal resources are allocated. The UE may perform communications associated with the first RAT based on selecting the resources.

Abstract: Methods, systems, and devices for wireless communications are described. Some wireless communication system support communications between user equipment (UEs). In the examples, a UE may include two or more transmission reception points (TRPs) and may transmit two or more packets on partially or fully overlapping resources via individual TRPs of the two or more TRPs. The UE may identify a first data packet for transmission using a first spatial layer associated with a first TRP and a second data packet for transmission using a second spatial layer associated with a second TRP. The UE may map a portion of the first data packet to a set of resources of the second spatial layer and transmitting a control message indicating that the portion of the first data packet is mapped to the second spatial layer.

Abstract: Aspects presented herein may improve joint communication-radar system by providing a radar reference signal with GI-FMCW waveform. Aspects presented herein may be compatible with communication-centric waveforms and thereby may apply to UEs or network entities with minimal changes if specified. In one aspect, a wireless device transmits a set of communication signals. The wireless device configure one or more parameters associated with a set of radar reference signals for radar sensing based on the set of communication signals, each radar reference signal in the set of radar reference signals including a guard interval. The wireless device transmits the set of radar reference signals associated with the one or more parameters.

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: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may configure sidelink control information (SCI) to indicate a plurality of sidelink transmission opportunities that are to be reserved for the UE. The UE may transmit the SCI to one or more other UEs. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communication at a user equipment (UE) are described. A first user equipment (UE) may transmit, to a second UE, sidelink control information (SCI) including an indication of resources and a number of spatial layers for a sidelink transmission. The first UE may perform spatial domain multiplexing (SDM) between the spatial layers. The first UE may transmit a first data packet associated with the first spatial layer from a first transmission reception point (TRP) and may transmit a second data packet associated with a second spatial layer from a second TRP. In some examples, the first UE may include a first and second stage of the SCI, such that the first SCI corresponds to shared information for all spatial layers and the second stage of the SCI corresponds to separate information for each spatial layer.

Abstract: Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may belong to a group of UEs that includes at least a second UE and a third UE. The first UE may perform a channel access procedure and, when the channel access procedure is successful, may transmit a first positioning reference signal (PRS) over a sidelink communication link to the second and third UEs. The first UE may transmit the first PRS during a first time interval of a transmission window. Based on receiving the first PRS, the second UE may perform a channel access procedure and may transmit a second PRS to the first UE during a second time interval of the transmission window. The second PRS may be multiplexed (e.g., using frequency division multiplexing (FDM) or code division multiplexing (CDM)) with at least a third PRS transmitted by the third UE.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive information indicative of one or more sets of redundancy version available for sidelink communications. Each set of redundancy versions may be associated with one or more conditions for use of a respective set. The UE may determine that one or more conditions for a first set of the one or more sets of redundancy versions are satisfied. The UE may select the first set for transmission of a sidelink message based on the satisfaction of the one or more conditions associated with the first set. The UE may transmit the sidelink message to a second UE using a redundancy version included within the first set of redundancy versions.

Abstract: Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may identify feedback indications and collision indications to transmit to a second UE. A feedback indication may indicate whether sidelink data was received and decoded successfully by the first UE, and a collision indication may indicate an expected conflict between the second UE and a third UE. In one aspect, the first UE may generate a feedback message including both feedback indications and collision indications, and the first UE may prioritize the feedback message based on the feedback indications, the collision indications, or both. In another aspect, the first UE may avoid including collision indications in a same feedback message as feedback indications.

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: Methods, systems, and devices for wireless communications are described. User equipments (UEs) may transmit sidelink control information (SCI) messages indicating reservations for upcoming sidelink transmissions in the same reserved resource. One of the UEs or another UE may detect a collision in the reserved resource based on the SCI messages. A feedback channel resource for indicating the collision may be calculated based on a time domain parameter of a resource mapping between time domain resources of the sidelink feedback channel and time domain resources of the reserved resource or a frequency domain parameter of a resource mapping between frequency domain resources of the sidelink feedback channel and frequency domain resources of the SCI message. A UE may transmit a collision indication in the calculated feedback channel resource. The UEs that transmitted the SCI messages may monitor the calculated feedback channel resource for a collision indication for the reserved resource.

Abstract: Aspects relate to a demodulation reference signal (DMRS) in a sidelink wireless communication network. In some examples, a sidelink device generates a DMRS based on first and second identifiers of the sidelink device. In some examples, a sidelink device generates a DMRS based on an initialization parameter and/or at least one scaling parameter. In some examples, the initialization parameter may be based on a first identifier of a sidelink device. In some examples, the at least one scaling parameter may be based on a second identifier of a sidelink device. In some examples, a first sidelink device synchronizes with a second sidelink device based on broadcast channel information that is obtained by using DMRS information to decode a received broadcast signal. In some examples, the DMRS information may be based on first and second identifiers of the first sidelink device.

Abstract: Techniques are provided for sidelink positioning with a single anchor using distributed antenna systems. An example method for determining relative locations of two stations includes determining a first round trip time for positioning reference signals transmitted between a first station and a first antenna of a second station, determining a second round trip time for the positioning reference signals transmitted between the first station and a second antenna of the second station, wherein the first antenna and the second antenna are disposed in different locations proximate to the second station, and determining relative locations of the first station and the second station based at least in part on the first round trip time and the second round trip time.

Abstract: Methods, systems, and devices for wireless communications are described. A cellular user equipment (C-UE) and vehicle UE (V-UE) may perform a discovery process. The C-UE and the V-UE may exchange identification and location information. One of the UEs may communicate the identification information of one or both of the UEs to a base station or a sidelink wireless device. The base station and the sidelink wireless device may be co-located. Based on the identification information of the C-UE and the V-UE, the base station may determine that the C-UE and the V-UE are co-located, and the base station may perform downlink transmissions based on the determined co-location.

Abstract: Certain aspects of the present disclosure provide a method for wireless communication at a first user equipment (UE). The method generally includes receiving, from a second UE, sidelink control information (SCI) scheduling a physical sidelink shared channel (PSSCH), determining a sequence for providing feedback for the PSSCH, from a plurality of possible sequences, based on one or more parameters, and transmitting the sequence via a physical sidelink feedback channel (PSFCH) as feedback for the PSSCH.

Abstract: Methods, systems, and devices for wireless communications are described. The method includes receiving, from a second UE, a discontinuous transmission configuration for a sidelink connection between the first UE and the second UE, determining, based on the received discontinuous transmission configuration, a set of receive beams for discontinuous reception by the first UE for the sidelink connection, and transmitting, to the second UE, a discontinuous reception configuration that indicates the determined set of receive beams for discontinuous reception for the sidelink connection.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit route information indicating a route associated with the UE. The UE may receive, based at least in part on transmitting the route information, configuration information indicating at least one other UE assigned to the UE for sidelink positioning. Numerous other aspects are described.