Abstract: Disclosed are techniques for wireless positioning. In an aspect, a user equipment (UE) may send, to a first entity, first information indicating a maximum number of positioning signal transmissions or a maximum power for positioning signal transmissions that the UE can support. The UE may receive, from the first entity, configuration information for changing a positioning mode of the UE to a positioning mode selected from a first positioning mode and a second positioning mode. The UE may perform a positioning operation according to the selected positioning mode. In some aspects, the first positioning mode is a normal positioning mode in which the UE sends UL positioning reference signals to a plurality of TRPS, and the second positioning mode is a UL power-limited mode in which the UE sends UL positioning reference signals to only one or a small number of TRPs.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first device may encode a data set using one or more extraction operations and compression operations associated with a neural network, the one or more extraction operations and compression operations being based at least in part on a set of features of the data set to produce a compressed data set. The first device may transmit the compressed data set to a second device. Numerous other aspects are provided.

Abstract: A positioning reference signal measurement method includes: receiving, at a user equipment from a network entity, an OFDM PRS (orthogonal frequency division multiplexing positioning reference signal) comprising a first set of first OFDM symbols that are consecutive and include a first center symbol and at least one pair of first side symbols disposed symmetrically about the first center symbol and having identical resource element sounding patterns; combining the first side symbols in each of the at least one pair of first side symbols to produce at least one first combined symbol; and determining a measurement of the OFDM PRS based on the at least one first combined symbol and the first center symbol.

Abstract: A technique is performed at a user equipment (UE) for supporting one or more radio frequency (RF) sensing measurements. A reflected downlink signal is received, wherein the reflected downlink signal is transmitted as a downlink signal from a base station and reflected off of a target. An uplink signal is transmitted to be reflected off of the target and received by the base station as a reflected uplink signal. A UE receive-transmit (RX-TX) time difference is determined, representing a difference between a time at which the reflected downlink signal is received by the UE and a time at which the uplink signal is transmitted by the UE. A UE measured frequency offset is determined based on reception of the reflected downlink signal, the UE measured frequency offset comprising a Doppler shift component corresponding to a velocity of the target.

Abstract: Certain aspects relate to techniques for z-axis rotation estimation for compensating signaling transmitted between two or more nodes over a wireless channel where an antenna array of at least one of the nodes is misaligned about the z-axis relative to another node. For example, a transmitting node may transmit pilot signals defined by phase shifts to provide a receiving node with a basis for estimating the angle of rotation by which the antenna arrays are misaligned. The transmitting node may then take remedial action to address the misalignment based on the estimation.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may select a non-Discrete Fourier Transform (non-DFT) codebook of a set of non-DFT codebooks associated with a channel state feedback message. The UE may determine a set of singular vectors associated with the non-DFT codebook based on a first machine learning model, where the set of singular vectors corresponds to a subspace associated with the non-DFT codebook. The UE may compress the non-DFT codebook, the set of singular vectors, or both, based on a second machine learning model. The UE may transmit the channel state feedback message including the compressed non-DFT codebook, the compressed set of singular vectors, or both.

Abstract: In an aspect, a wireless node performs a first RSRP measurement of an RS-P based on a first set of samples within a first time window of an RS-P symbol or resource, and determines whether a spoofing attack is associated with RS-P based on the first RSRP measurement and one or more other RSRP measurements of one or more other sets of samples within one or more earlier time windows of the RS-P symbol or resource. The wireless node transmits, to a communications device (e.g., position estimation entity), an indication (e.g., in a measurement report) of the spoofing attack determination. The communications device performs at least one action based at least in part upon the indication of the spoofing attack determination.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may determine a configuration of a retransmission of a first message of a random access procedure based on a set of transmission configuration options transmitted by a base station. For example, the UE may transmit the first message but may reconfigure the first message for the retransmission based on the transmission configuration options. Additionally, the UE may configure a set of transmission configuration states based on the transmission configuration options for transmitting/retransmitting the first message. In some cases, the UE may determine to switch transmission configuration states based on a trigger signaled by the base station and/or a determination by the UE. Additionally, the UE may transmit an indication of a log of state transitions performed prior to a retransmission of the first message to facilitate combining of the retransmissions at the base station.

Abstract: A method of wireless communication by a transmitting device transforms a transmit waveform by an encoder neural network to control power amplifier (PA) operation with respect to non-linearities. The method also transmits the transformed transmit waveform across a propagation channel. A method of wireless communication by a receiving device receives a waveform transformed by an encoder neural network. The method also recovers, with a decoder neural network, the encoder input symbols from the received waveform. A transmitting device for wireless communication calculates distortion error based on a non-distorted digital transmit waveform and a distorted digital transmit waveform. The transmitting device also compresses the distortion error with an encoder neural network of an auto-encoder. The transmitting device transmits to a receiving device the compressed distortion error to compensate for power amplifier (PA) non-linearity.

Abstract: Methods, systems, and devices for wireless communications are described. A first wireless device may transmit, to a second wireless device, a message indicating a capability of the first wireless device to support full-duplex line-of-sight (LOS) multiple-input multiple-output (MIMO) communications. The first wireless device may receive, from the second wireless device, control signaling indicating an uplink channel resource allocated for one or more uplink communications, a downlink channel resource allocated for one or more downlink communications, a first set of LOS MIMO transmission modes for the one or more uplink communications, and a second set of LOS MIMO transmission modes for the one or more downlink communications. The uplink channel resource may at least partially overlap with the downlink channel resource in time, frequency, or both. The first wireless device may communicate the one or more uplink communications and the one or more downlink communications based on the control signaling.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless device may transmit feedback, such as hybrid automatic repeat request (HARQ) feedback for groups of code blocks rather than for an entire transport block or individual code blocks. The wireless device may transmit an acknowledgement (ACK) or negative-acknowledgement (NACK) to provide feedback for each code block group of a set of code block groups. An ACK may indicate that code blocks in a code block group were successfully decoded, and a NACK may indicate that at least one code block in a code block group was not successfully decoded. Wireless devices may support several techniques for grouping code blocks for feedback reporting to allow for efficient retransmissions and limited overhead. Different grouping schemes may be employed depending on system constraints, device capability, link conditions, or the like.

Abstract: A UE includes: a transceiver; a memory; and a processor configured to: receive first and second discontinuous reception configurations for first and second discontinuous reception groups; receive first and second positioning signal configurations for first and second positioning signals associated with the first and second discontinuous reception groups, respectively; measure the first positioning signal during a first active time of the first discontinuous reception group; and measure the second positioning signal during a fixed second active time or during a variable third active time, the fixed second active time having a fixed duration of the second discontinuous reception group and the variable third active time having a variable duration of the second discontinuous reception group.

Abstract: Methods, systems, and devices for wireless communications are described. A transmitted may use a closed loop precoder for line-of-sight (LOS) multiple-input multiple-output (MIMO) communications that uses information such as distance feedback or LOS MIMO channel state feedback. A closed loop precoder may be associated with less overhead than a precoder based on full channel knowledge, such as an SVD precoder. A receiver may estimate a channel based on channel state information reference signals transmitted by the transmitter and calculate a spectral efficiency for one or more precoders of a set of precoders associated with the channel for a LOS MIMO mode. The receiver may send feedback to the transmitter that indicates a selected precoder of the set of LOS MIMO precoders based on the calculated spectral efficiencies. The transmitter may precode messages using the reported closed loop precoder.

Abstract: In an aspect, a UE obtains information (e.g., UE-specific information, etc.) associated with a set of triggering criteria for a set of neural network functions, the set of neural network functions configured to facilitate positioning measurement feature processing at the UE, the set of neural network functions being generated dynamically based on machine-learning associated with one or more historical measurement procedure, obtains positioning measurement data associated with a location of the UE, and determines a positioning estimate for the UE based at least in part upon the positioning measurement data and at least one neural network function from the set of neural network functions that is triggered by at least one triggering criterion from the set of triggering criteria.

Abstract: In an aspect, a UE obtains information (e.g., UE-specific information) associated with a set of triggering criteria (e.g., from a server, a serving network, e.g., in conjunction with or separate from a set of neural network functions) for a set of neural network functions, the set of neural network functions configured to facilitate positioning measurement feature processing at the UE, the set of neural network functions being generated dynamically based on machine-learning associated with one or more historical measurement procedures. The UE obtains positioning measurement data associated with a location of the UE, and processes the positioning measurement data into a respective set of positioning measurement features based at least in part upon the positioning measurement data and at least one neural network function from the set of neural network functions that is triggered by at least one triggering criterion from the set of triggering criteria.

Abstract: Sounding reference signals (SRS) transmitted by a UE, e.g., for positioning or channel estimation, may be configured for one or both of frequency tone level cyclic shift and symbol level code, which, for example, enables multiplexing a greater number of UEs. The frequency tone level cyclic shift is produced by jointly processing a number of symbols with an extended cyclic shift structure. The SRS may be configured using a symbol group level that indicates the number of symbols associated with a cyclic shift structure, and an outer code that indicates a multiplier applied to the SRS at the symbol level, which increases the multiplexing opportunities. The symbol level code may further indicate an extended cyclic shift indicating a linear increase in phase rotation across tones in symbols associated with the symbol group level.

Abstract: Fallback procedures for user equipments (UEs) are described that provide efficient fallback to a four-step random access procedure from a two-step random access procedure. For example, after transmitting a first message of a two-step random access procedure, a UE may start a fallback timer or counter and monitor for a second message of the two-step random access procedure for the duration of the fallback timer or counter. At the expiration of the fallback timer or counter, the UE may fall back to a four-step random access procedure. In some cases, the UE may transmit multiple repetitions of the first message and monitor for responses after transmitting the repetitions or after each repetition. Additionally, or alternatively, the base station may transmit an explicit signal to the UE that may signal to the UE to perform a fallback procedure at a beginning or middle of a random access procedure.

Abstract: A base station may identify a first antenna configuration of the base station and a second antenna configuration of a wireless device. The base station may select one or more codebook-based precoders for communication with the wireless device with LOS MIMO. The one or more codebook-based precoders may include at least one of a Legendre precoder, a block-DFT precoder, a DFT precoder, a block-Walsh precoder, a Walsh precoder, a block-Legendre precoder, a Kronecker Legendre precoder, a Kronecker block-DFT precoder, or a Kronecker block-Walsh precoder. The base station may transmit, to a wireless device, an indication of a second codebook-based precoder for transmission from the wireless device to the base station with LOS MIMO. The base station and the wireless device may communicate with each other with LOS MIMO based on one or more codebook-based precoders.

Abstract: A method of wireless communication by a user equipment (UE) includes receiving, from a base station, a configuration to train a neural network for multiple different signal to noise ratios (SNRs) of a channel estimate for a wireless communication channel. The method also includes determining a current SNR of the channel estimate is above a first threshold value. The method further includes training the neural network based on the channel estimate, to obtain a first trained neural network. The method still further includes perturbing the channel estimate to obtain a perturbed channel estimate, and training the neural network based on the perturbed channel estimate, to obtain a second trained neural network. The method includes reporting, to the base station, parameters of the first trained neural network along with the channel estimate, and parameters of the second trained neural network.

Abstract: Methods, systems, and devices for wireless communications are described. A transmitter may select a precoder from a codebook for precoding one or more signals for transmission to a receiver. The transmitter may select the precoder from the codebook based on antenna configurations at the transmitter and the receiver. The precoder may be constructed using one or more Slepian sequences. In some implementations, the Slepian sequences may be associated with a quantity of transmit antennas at the transmitter. For instance, a length of each Slepian sequence may correspond to (for example, be equal to) a quantity of transmit antennas at the transmitter. Further, the Slepian sequences may be associated with a bandwidth within which to concentrate the one or more signals. Once the transmitter selects the precoder, the transmitter may precode the one or more signals and transmit the precoded signals to the receiver.