Abstract: A transmitting device maps complex valued symbols in sequence to physical resource blocks for a sidelink transmission. The transmitting device reserves a first symbol of a subframe, where resource elements in the first symbol of the subframe are not considered in mapping the complex valued symbols to the physical resource blocks for the sidelink transmission. The transmitting device transmits the sidelink transmission after mapping the complex valued symbols to the physical resource blocks. A receiving device receives the sidelink transmission and decodes the sidelink transmission to determine complex valued symbols that are mapped in sequence to physical resource blocks of the sidelink transmission, where the complex valued symbols are not mapped to resource elements in a first symbol of a subframe.

Abstract: Methods, systems, and devices for wireless communications are described for estimating one or more environmental factors at a first user equipment (UE). The one or more environmental factors may be based on estimates of a Doppler spread and a power delay profile (PDP) taken over a set of subsets of a time period, based on multiple signals received from a second UE or a base station over the time period. The first UE may estimate the Doppler spread and PDP for a channel over each of the set of subsets of the time period, and may combine the Doppler spread over the set of subsets and combine the PDP over the set of subsets. The first UE may use the combined Doppler spread and the combined PDP to determine one or more communication parameters for the channel.

Abstract: Methods, systems, and devices for wireless communications are described. In a wireless communications system, a first user equipment (UE) may receive a message from a second UE via a set of one or more antennas, where a first symbol period and a second symbol period of the message include a duplicated signal, and the first symbol period is immediately prior to the second symbol period in a time domain. The first UE may calculate a correlation between first data included in the first symbol period and second data included in the second symbol period of the message for each antenna of the set of one or more antennas. In some cases, the first UE may power down at least one radio frequency chain based on the result of the calculated correlation satisfying a threshold value.

Abstract: Methods, systems, and devices for wireless communications are described to support estimation of a transmission quality imbalance between a set of antennas of a first user equipment (UE). The first UE may use the estimated transmission quality imbalance to determine a transmission diversity scheme that may decrease the transmission quality imbalance. The first UE may determine the transmission quality imbalance between the set of antennas by estimating a reception quality imbalance between the set of antennas. The first UE may estimate the reception quality imbalance for multiple subsets of a time period and may combine the reception quality imbalance estimations for the multiple subsets. The combined reception quality imbalance estimations may represent the transmission quality imbalance between the set of antennas, which may be used to determine a transmission diversity scheme for communicating a transmission to a second UE or a base station.

Abstract: Methods, systems, and devices for wireless communications are described. In a wireless communications system, a first user equipment (UE) may receive a message from a second UE via a set of one or more antennas, where a first symbol period and a second symbol period of the message include a duplicated signal, and the first symbol period is immediately prior to the second symbol period in a time domain. The first UE may calculate a correlation between first data included in the first symbol period and second data included in the second symbol period of the message for each antenna of the set of one or more antennas. In some cases, the first UE may power down at least one radio frequency chain based on the result of the calculated correlation satisfying a threshold value.

Abstract: Methods, systems, and devices for wireless communications are described. A base station may transmit an indication of a demodulator configuration to a user equipment (UE) for the UE to use that demodulator configuration for demodulating a multi-layer transmission from the base station. The base station may determine the demodulator configuration for the UE to use based on one or more uplink signals transmitted from the UE. Additionally, the UE may transmit an indication of demodulator capabilities that the UE supports to the base station, where the base station determines the demodulator configuration based on the indication of the demodulator capabilities. In some examples, the demodulator configuration may indicate a demodulation search space corresponding to a number of layers included per layer group of the multi-layer transmission, may correspond to an amount of cross correlation determined between respective layers of the multi-layer transmission, or a combination thereof.

Abstract: A transmitting device maps complex valued symbols in sequence to physical resource blocks for a sidelink transmission. The transmitting device reserves a first symbol of a subframe, where resource elements in the first symbol of the subframe are not considered in mapping the complex valued symbols to the physical resource blocks for the sidelink transmission. The transmitting device transmits the sidelink transmission after mapping the complex valued symbols to the physical resource blocks. A receiving device receives the sidelink transmission and decodes the sidelink transmission to determine complex valued symbols that are mapped in sequence to physical resource blocks of the sidelink transmission, where the complex valued symbols are not mapped to resource elements in a first symbol of a subframe.

Abstract: Methods, systems, and devices for wireless communications are described. In a wireless communications system, a user equipment (UE) may be configured to use intra-message antenna selection diversity (ASD). The UE may transmit a first portion of a scheduled message within a time interval using a first antenna element of the UE based on an intra-message antenna diversity configuration. The intra-message antenna diversity configuration may indicate a set of antennas available for transmission of the scheduled message. In some cases, the UE may transmit, within the same time interval, at least a portion of the scheduled message using at least a second antenna element of the UE that is different from the first antenna element. In some cases, a receiving UE may decode the first portion and the second portion of the scheduled message based on the intra-message antenna diversity configuration.

Abstract: Certain aspects of the present disclosure provide techniques for wireless communication by a first wireless device. The first wireless device may participate in a beam forming procedure with a second wireless device to evaluate a plurality of transmit (TX) and receive (RX) beam pairs. The first wireless device may select one of the TX and RX beam pairs based on the evaluation. The first wireless device may determine at least one cryptographic key based on channel parameters associated with a selected one of the TX and RX beam pairs. The first wireless device may use the at least one cryptographic key for communications with the second wireless device.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may configure one or more transmission parameters based at least in part on an average channel condition estimate for a broadcast channel, wherein the broadcast channel is for broadcast communications or groupcast communications for multiple mobile UEs. The UE may transmit a broadcast communication or a groupcast communication using the one or more transmission parameters. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications are described. One or more UEs communicating over sidelink may indicate transmit and receive categories to other UEs. A first UE may receive, in a sidelink communication message, an indication of a receive category of a second wireless device. The first UE may then transmit a shared sidelink channel message to the second wireless device based on the receive category of the second wireless device. In another case, a first UE may receive, in a sidelink communication message, an indication of a transmit category of a second wireless device. The first wireless device may then compare the transmit category of the second wireless device with a receive category of the first wireless device. The first wireless device may determine whether to decode a shared sidelink channel message from the second UE based on the comparing.

Abstract: Aspects relate to mechanisms for a wireless communication device to select between a cyclic delay diversity mode and an antenna switch diversity mode for transmission of a signal based on at least one parameter associated with communication over a wireless channel. The parameter(s) may include a channel estimation parameter associated with the wireless channel, a communication parameter associated with at least one communication on the wireless channel, or a combination thereof.

Abstract: Methods, systems, and devices for wireless communications are described. A first wireless device may identify a reference signal sequence (e.g., a demodulation reference signal (DMRS) sequence) based on a cyclic shift associated with a control channel for communications with a second wireless device. For example, the first wireless device may identify the cyclic shift associated with transmitting a message to the second wireless device via the control channel. In another example, the first wireless device may estimate the cyclic shift associated with receiving a message from the second wireless device via the control channel. The first wireless device may then communicate with the second wireless device based on the reference signal sequence. For example, the first wireless device may transmit or receive (e.g., via a shared channel) the reference signal sequence to or from the second wireless device.

Abstract: Certain aspects of the present disclosure provide techniques for wireless communication by a first wireless device. The first wireless device may participate in a beam forming procedure with a second wireless device to evaluate a plurality of transmit (TX) and receive (RX) beam pairs. The first wireless device may select one of the TX and RX beam pairs based on the evaluation. The first wireless device may determine at least one cryptographic key based on channel parameters associated with a selected one of the TX and RX beam pairs. The first wireless device may use the at least one cryptographic key for communications with the second wireless device.

Abstract: Disclosed are techniques for wireless communication. In some aspects, a base station (BS) may determine a first planned transmit beam configuration of the first BS. The BS may obtain a second planned transmit beam configuration of a second BS. The BS may determine that a first planned transmit beam of the first planned transmit beam configuration will interfere with a second planned transmit beam of the second planned transmit beam configuration. The BS may modify the first planned transmit beam, the second planned transmit beam, or both, based on the interference determination.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may increase a transmission power for a physical sidelink shared channel (PSSCH) communication based at least in part on decreasing a transmission power for a physical sidelink control channel (PSCCH) communication. The UE may transmit the PSCCH communication using the decreased transmission power for the PSCCH communication and transmit the PSSCH communication using the increased transmission power for the PSSCH communication. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A first wireless device may identify a reference signal sequence (e.g., a demodulation reference signal (DMRS) sequence) based on a cyclic shift associated with a control channel for communications with a second wireless device. For example, the first wireless device may identify the cyclic shift associated with transmitting a message to the second wireless device via the control channel. In another example, the first wireless device may estimate the cyclic shift associated with receiving a message from the second wireless device via the control channel. The first wireless device may then communicate with the second wireless device based on the reference signal sequence. For example, the first wireless device may transmit or receive (e.g., via a shared channel) the reference signal sequence to or from the second wireless device.

Abstract: A communications device inputs channel state information to an artificial neural network. The communications device predicts weather conditions with the artificial neural network based on the channel state information. The communications device further adjusts communications based on the predicted weather conditions.

Abstract: The present disclosure involves determining base station (BS) beams for communicating between a UE and the BS. The BS may use sensor data or beam management reporting history to assist with determining one or more appropriate beams. The sensor data may include camera images, radar data, or lidar data, and be used to model the cell environment served by the BS. The BS may obtain reporting data from multiple UEs over time indicating the quality of beams received by the UEs at various locations in the cell environment and model the cell environment based on the reporting data. The BS may associate beams with possible UE locations within the cell environment and use the associations to determine beams for communicating with a UE after determining the UE's location.

Abstract: Methods, systems, and devices for wireless communications are described to support estimation of a transmission quality imbalance between a set of antennas of a first user equipment (UE). The first UE may use the estimated transmission quality imbalance to determine a transmission diversity scheme that may decrease the transmission quality imbalance. The first UE may determine the transmission quality imbalance between the set of antennas by estimating a reception quality imbalance between the set of antennas. The first UE may estimate the reception quality imbalance for multiple subsets of a time period and may combine the reception quality imbalance estimations for the multiple subsets. The combined reception quality imbalance estimations may represent the transmission quality imbalance between the set of antennas, which may be used to determine a transmission diversity scheme for communicating a transmission to a second UE or a base station.