Various schemes pertaining to optimization of distributed resource unit (RU) tone plans for peak-to-average power ratio (PAPR) reduction in 6 GHz low-power indoor (LPI) systems are described. An apparatus distributes a plurality of subcarriers of a RU over a bandwidth to generate a distributed-tone RU (dRU) or a distributed-tone multi-RU (dMRU). The apparatus then communicates with a communication entity using the dRU or the dMRU. In distributing the plurality of subcarriers of the RU to generate the dRU or the dMRU, the apparatus distributes the plurality of subcarriers of the RU with a predefined span over each 20 MHz frequency segment or subblock in the bandwidth and with a gap of at least a minimum size around a center direct-current (DC) tone in a distribution pattern of the plurality of subcarriers to result in reduction in a PAPR in communicating with the communication entity.

The apparatus may be a base station. The apparatus processes a first group of synchronization signals. The apparatus processes a second group of synchronization signals. The apparatus performs a first transmission by transmitting the processed first group of the synchronization signals in a first synchronization subframe. The apparatus performs a second transmission by transmitting the processed second group of the synchronization signals in a second synchronization subframe.

Disclosed is a relay method including: receiving, as input, respective reception signals by two receive antennas, the reception signals each including a reception signal resulting from multiplexing respective transmission signals transmitted by two transmission antennas in a first frequency band; performing frequency conversion on the reception signal received by one of the receive antennas so as to obtain a signal of a third frequency band; and performing frequency multiplexing on the signal having the third frequency band and the reception signal received by the other of the receive antennas.

A UE may identify a plurality of local model update elements associated with an updated local machine learning model. The updated local machine learning model may have been generated based on a global machine learning model received from a base station and a local dataset. The UE may identify one or more local model update elements of the plurality of local model update elements for update element dropping based on at least one of a channel gain, a PAPR specification, an RF emission specification, or an RF condition. The UE may transmit, to the base station over a multiple access channel via analog signaling, at least some local model update elements of the plurality of local model update elements based on dropping of the identified one or more local model update elements.

Methods, systems, and devices for wireless communications are described. Autonomous transmissions between a user equipment (UE) and a base station may be configured that include at least one of a modulation and coding scheme (MCS) or resources for the transmissions. In some cases, a trigger may be detected that changes the MCS or resources to be used for the autonomous transmissions. The trigger may include the presence or absence of retransmissions or the value of a channel measurement falling below or exceeding a threshold value. Accordingly, the base station and UE may adjust the MCS or resources to be used for the autonomous transmissions based on detecting the trigger and then communicate using the adjusted MCS or resources. In some cases, the configuration for the autonomous transmissions may be signaled via a medium access control (MAC) control element (CE).

System and methods for shaped single carrier orthogonal frequency division multiplexing with low peak to average power ratio are provided. The system receives an input signal and modulates the input signal to form Dirichlet kernels in a time domain to generate an offset Dirichlet kernel output time array where each Dirichlet kernel has a main lobe and a plurality of side lobes. Modulating the input signal suppresses a peak to average power ratio of the offset Dirichlet kernel output time array by reducing the plurality of side lobes of each Dirichlet kernel and respective amplitudes of the side lobes.

Aspects presented herein may improve the efficiency and performance of the tone reservation PAPR reduction technique by allocating peak reduction tone based at least in part on a channel condition, such as based on the signal to noise ratio of the channel. In some aspects, a transmitting device measures a signal to noise ratio for a plurality of tones within a frequency resource. The transmitting device selects a location of one or more reserved tones (e.g., peak reduction tones) among one or more tones based at least in part on an SNR for one or more tones. The transmitting device transmits data to a receiving device in a subset of the plurality of tones that does not include the one or more peak reduction tones. Other aspects and features are also disclosed.

A discrete Fourier transform spread orthogonal time frequency space modulation method comprises the steps of performing DFT preceding processing and delay-Doppler domain mapping processing on the transmit data symbols, OTFS modulator, and performing delay-Doppler domain demapping processing and IDFT decoding processing on a received signal to realize demodulation; compared with the existing waveforms, including OFDM and DFT-s-OFDM, the proposed DFT-s-OTFS can reduce the bit error rate under high Doppler spread and the peak-to-average power ratio of the transmitted signal at the same time.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may perform both a channel estimation and a non-linearity estimation (e.g., a power amplifier (PA) model estimation) on a demodulation reference signal (DMRS) transmitted by a base station. For example, the DMRS may include two portions that correspond to two peak-to-average power ratio (PAPR) values. Low PAPR values may enable the UE to perform the channel estimation, and high PAPR values may enable the UE to perform the PA non-linearity estimation. Accordingly, a first portion of the DMRS may correspond to a lower PAPR value, and the second portion of the DMRS may correspond to a higher PAPR value. In some examples, the base station may signal different parameters for each portion of the DMRS to the UE, or the UE may use fixed values to receive each portion of the DMRS.

An Orthogonal Frequency Division Multiplexing (OFDM) transmitter generates OFDM multiple-access signals with low Peak-to-Average-Power Ratio (PAPR). A code-division multiplexer arranges original data symbols from different data streams inside each length-N symbol block, which is spread by a Discrete Fourier Transform (DFT) spreader. The arrangement of the original data symbols configures the DFT spreader to spread each original data symbol into a predetermined spread-DFT code division multiple access channel. The resulting DFT-spread data symbols are mapped to OFDM subcarriers, and an inverse discrete Fourier transform (IDFT) operates on the DFT-spread data symbols to generate an OFDM transmission signal having low PAPR.