Abstract: The described techniques may support multi-rank sidelink communications that may be reduced to single rank communications if failure to decode the multi-rank sidelink communications occurs. A user equipment (UE) may transmit a first message including first data using a first precoding vector applied for a first layer and a second precoding vector applied for a second layer. If the first message is not decoded successfully, the UE may transmit a second message including second data using a third precoding vector applied for the first layer and a fourth precoding vector applied for the second layer, where the second data is derived from the first data, the third precoding vector is derived from the second precoding vector, and the fourth precoding vector is derived from the first precoding vector. The second message may effectively reduce a rank of the first message when the channel is rank deficient.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive, from a transmitting device, an indication of an instantaneous gain associated with an amplitude distortion associated with frequency division multiplexed downlink communications to the UE from the transmitting device. The UE may receive the frequency division multiplexed downlink communications from the transmitting device over frequency resources allocated to the UE, wherein receiving the frequency division multiplexed downlink communications comprises applying a digital post distortion model to the frequency division multiplexed downlink communications according to the instantaneous gain.

Abstract: A base station may identify one or more signaling messages or pilots usable for identifying a combined PA and ET non-linearity model associated with the base station. The combined PA and ET non-linearity model may be associated with a PA circuitry and an ET circuitry. The PA circuitry and the ET circuitry may be associated with the base station. The base station may transmit, to the UE, and the UE may receive, from the base station, the one or more signaling messages or pilots. The UE may identify a combined PA and ET non-linearity model associated with the base station based on the one or more signaling messages or pilots. The UE may compensate for a distortion in one or more subsequent signals from the base station based on the identified combined PA and ET non-linearity model.

Abstract: Methods, systems, and devices for wireless communications are described. A transmitting device may select a scrambling sequence to use per symbol to reduce variance in a non-linearity parameter for a power amplifier (PA) output between a data symbol and a pilot symbol based on a PA model for at least one pilot symbol or one or more parameters of the model. The receiving device may indicate a capability to blindly estimate the scrambling sequence the transmitting device selected to the transmitting device. If the transmitting device does not receive the capability message from the receiving device or if the capability message indicates the receiving device is not capable of blind estimation, the transmitting device may indicate the selected scrambling sequence to the receiving device. Otherwise, the transmitting device may not indicate the selected scrambling sequence to the receiving device, and the receiving device may blindly estimate the scrambling sequence.

Abstract: Methods, systems, and devices for wireless communications are described. The methods include a base station mapping transmitter antennas to one of a set of multiple antenna groups based on a power amplifier response of one or more transmitter antennas, determining a power amplifier model for one or more antenna groups based on the power amplifier response of the one or more transmitter antennas, and transmitting an indication of the power amplifier model for one or more antenna groups to a UE. The methods include the UE determining a power amplifier model for a transmitter antenna of the set of transmitter antennas based on the indication of the power amplifier model and communicating with the base station based on the power amplifier model for the transmitter antenna.

Abstract: Certain aspects of the present disclosure provide techniques for envelope tracking schemes for a node in a wireless communication network. One aspect provides a method for wireless communication by a transmitter device. The method generally includes: combining envelopes associated with subbands of an input signal to be amplified for transmission based on a combination function; amplifying, via an amplifier, the input signal to generate a transmission signal, the input signal being amplified based on a combined envelope signal, representing the combination of the envelopes, received at a supply input of the amplifier; and transmitting the transmission signal to a receiver device.

Abstract: This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for performing wireless communication using digital post distortion, for example, with a large antenna array where the number of transmit antennas may be greater than a number of spatial streams. A transmitting device and a receiving device determine a perturbed precoding matrix based on a precoding perturbation rule. The transmitting device precodes a signal using the perturbed precoding matrix and transmits via the number of antennas greater than the number of spatial streams. The receiving device receives the signal and subtracts non-linearities from the received signal based on a channel estimation using the perturbed precoding matrix over one or more iterations.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication of a configuration for balanced code communication, the configuration indicating parameters of signals of balanced code communications having sequences, within codewords, that balance. The UE may receive, from a network node, a balanced code communication, the receiving comprising decoding a codeword of the balanced code communication and estimating one or more parameters of communicating with the network node based at least in part on the configuration and based at least in part on using a balancing property of the balanced code communication. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a communication comprising data signaling and superimposed pilots, the superimposed pilots being superimposed on the data signaling transmitted via one or more communication resources of the communication. The UE may decode the data signaling from the communication. The UE may measure one or more channels of one or more beams based at least in part on the superimposed pilots. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a configuration of a sleep mode, the configuration indicating a coding scheme used for a wake-up signal (WUS). The UE may receive a WUS message, the WUS message being encoded with product coding, wherein a coding stage of the product coding comprises locally-decodable coding. The UE may receive a communication based at least in part on the WUS message. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, an UE may receive an indication of a configuration for receiving reference signals (RSs) and for transmitting a digital pre-distortion (DPD) measurement. The UE may receive the RSs from a network node. The UE may transmit a first signal that indicates the DPD measurement as observed via the RSs at the first UE, the first signal configured for coherent combination over the air with a second signal that indicates a DPD measurement as observed via the RSs at a second UE, the first signal and the second signal scheduled for transmission via overlapping network resources. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications are described. The methods include a base station mapping transmitter antennas to one of a set of multiple antenna groups based on a power amplifier response of one or more transmitter antennas, determining a power amplifier model for one or more antenna groups based on the power amplifier response of the one or more transmitter antennas, and transmitting an indication of the power amplifier model for one or more antenna groups to a UE. The methods include the UE determining a power amplifier model for a transmitter antenna of the set of transmitter antennas based on the indication of the power amplifier model and communicating with the base station based on the power amplifier model for the transmitter antenna.

Abstract: This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for non-linearity estimation techniques for digital post distortion (DPoD) in a wireless system. In some aspects, a first wireless device may estimate a power amplifier (PA) non-linearity associated with a second wireless device using select signaling from the second wireless device. For example, the first wireless device may use a received signal to estimate the PA non-linearity if a dynamic power range associated with the signal triggers the estimation of the PA non-linearity (such as if the dynamic power range associated with the signal satisfies, or is expected to satisfy, a threshold dynamic power range). If the dynamic power range of the signal triggers the estimation of the PA non-linearity, the first wireless device may introduce DPoD to signaling received from the second wireless device in accordance with the estimation of the PA non-linearity.

Abstract: Methods, systems, and devices for wireless communications are described. Techniques provide for reliable signal processing and amplification of downlink signals. A network entity may apply a digital pre-distortion (DPD) process to a signal for transmission to a user equipment (UE) and may apply a crest factor reduction (CFR) process to the output of the DPD process. The output of the CFR process may be amplified by a power amplifier and transmitted via a downlink transmission to the UE. The CFR process limits the peak power of the signal provided to the power amplifier (e.g., to a configured level), thereby reducing the peak to average power ratio (PAPR) of the signal provided to the power amplifier. The DPD process may compensate for non-linearities of the power amplifier. A training procedure for the DPD process may account for the CFR process applied after the DPD process.

Abstract: Methods, systems, and devices for wireless communications are described. Techniques provide for reliable signal processing and amplification of downlink signals. A network entity may apply a digital pre-distortion (DPD) process to a signal for transmission to a user equipment (UE) and may apply a crest factor reduction (CFR) process to the output of the DPD process. The output of the CFR process may be amplified by a power amplifier and transmitted via a downlink transmission to the UE. The CFR process limits the peak power of the signal provided to the power amplifier (e.g., to a configured level), thereby reducing the peak to average power ratio (PAPR) of the signal provided to the power amplifier. The DPD process may compensate for non-linearities of the power amplifier. A training procedure for the DPD process may account for the CFR process applied after the DPD process.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive data encoded based on a multi-level balanced code, codewords of the multi-level balanced code being selected based on a finite number of multiple sum values, corresponding to all constellation symbol sequences in the multi-level balanced code. The UE may receive a superimposed pilot (SIP) using communication resources occupied by the data. The UE may estimate one or more channel parameters based on the SIP and the multi-level balanced code. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications are described. A first wireless device may identify a set of data resource elements for transmitting data in one or more symbols periods. The first wireless device may generate, for the one or more symbol periods based on the set of data resource elements, a sequence of a set of pilot resource elements associated with the set of data resource elements, the sequence of the set of pilot resource elements including a phase tracking reference signal. The first wireless device may transmit, to a second wireless device in the one or more symbol periods, the set of data resource elements and the set of pilot resource elements. The second wireless device may decode a first subset of the set of pilot resource elements based on a second subset of the set of pilot resource elements to determine the phase tracking reference signal.

Abstract: This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for performing wireless communication using digital post distortion, for example, with a large antenna array where the number of transmit antennas may be greater than a number of spatial streams. A transmitting device and a receiving device determine a perturbed precoding matrix based on a precoding perturbation rule. The transmitting device precodes a signal using the perturbed precoding matrix and transmits via the number of antennas greater than the number of spatial streams. The receiving device receives the signal and subtracts non-linearities from the received signal based on a channel estimation using the perturbed precoding matrix over one or more iterations.

Abstract: An apparatus for wireless communication at a UE is provided. The apparatus is configured to receive one or more pilot signals superimposed on a data signal from a network entity. The apparatus is further configured to receive an indication of a first set of locations in at least one of time or frequency from the network entity. The data signal or the scrambled data signal is near orthogonal to a channel estimation filter of the transmission channel between the network entity and the UE at the first set of locations. The apparatus is further configured to transmit characteristics of the transmission channel to the network entity. The characteristics of the transmission channel is determined based at least in part on the first set of locations.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first network node may receive a distortion indication comprising distortion information associated with a signal transmission configuration corresponding to a second network node. The first network node may perform, based at least in part on the distortion information, a digital post distortion (DPoD) operation associated with a signal having a distortion characteristic corresponding to the distortion information. The first network node may communicate with the second network node based at least in part on performing the DPoD operation. Numerous other aspects are provided.