The method for transmitting, by a user equipment, a sidelink signal in a wireless communication system is a sidelink signal transmission method comprising: transmitting sidelink control information (SCI); mapping, to a plurality of sub-carriers, at least one complex-valued modulation symbol, which is related to a sidelink data signal, and a preset value; generating the sidelink data signal by modulating the at least one complex-valued modulation symbol and the preset value by orthogonal frequency division multiplexing (OFDM); and transmitting the sidelink data signal on the basis of the SCI, wherein the SCI comprises information regarding a sub-carrier set including at least one sub-carrier, to which the preset value is mapped, from among the plurality of sub-carriers, and at least one of the location and number in a frequency domain of the at least one sub-carrier, to which the preset value is mapped, is different for each sub-carrier set.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication that tone reservation is to be applied to one or more subcarriers for one or more downlink communications. The UE may transmit one or more uplink signals, using the one or more subcarriers, for measurement by a base station. The UE may receive the one or more downlink communications having the tone reservation applied to the one or more subcarriers, the one or more subcarriers having tone reservation applied based at least in part on the measurement of the one or more uplink signals on the one or more subcarriers. Numerous other aspects are described.

A method of determining reserved tones to be used for reduction of a peak to average power ratio (PAPR) of a signal includes: randomly selecting carrier indices for the reserved tones and generating a kernel signal based on the randomly selected carrier indices; calculating a comparison reference average value of the kernel signal, comparing the calculated comparison reference average value with a prestored comparison reference average value, and preliminarily determining carrier indices of the reserved tones based on the comparison; randomly re-arranging an order of the preliminarily determined carrier indices of the reserved tones; and calculating the comparison reference average value while changing each of the re-arranged indices of the reserved tones, and finally determining carrier indices for which the calculated comparison reference average value becomes the smallest value as carrier indices of the reserved tones.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive a resource allocation indicating a plurality of transmission tones comprising a subset of data tones of a plurality of data tones and a subset of peak reduction tones (PRTs) of a plurality of PRTs, wherein the resource allocation indicates locations for the plurality of data tones and locations for the plurality of PRTs within a particular bandwidth, wherein the locations for the plurality of PRTs are arranged relative to the locations for the plurality of data tones according to a PRT subsequence of a universal PRT sequence, and wherein the PRT subsequence corresponds to a sub-band of the particular bandwidth; and transmit a data transmission using a waveform based at least in part on the resource allocation. Numerous other aspects are provided.

Systems and methods are provided for reducing peak-to-average power ratio (“PAPR”) in an orthogonal frequency division multiplexing (“OFDM”) signal having reference tones by introducing modified pilot tones to cancel peaks in OFDM symbols in the OFDM signal array. The modified pilot tones are added to the original OFDM signal, which in turn conditions the OFDM symbols of the signal to effectively reduce the PAPR. Such systems and methods provide PAPR reduction for OFDM signals generated by an OFDM Signal Processor through the addition of tone reservation PAPR reduction methods, which use reserved tones such as pilot tones to improve PAPR. Such methods offer an advantage of improving the PAPR without introducing distortion to the signal.

This document discloses a solution for reducing peak-to-average power ratio in a radio device. According to an aspect, an apparatus includes circuitry configured for performing: acquiring a block of modulated symbols to be transmitted over a radio interface; transforming the block of modulated symbols from a time domain into a frequency domain for sub-carrier mapping; performing a time-domain peak detection procedure on the block of modulated symbols before said transforming; upon detecting at least one peak in the block of modulated symbols during the time-domain peak detection procedure, computing a peak correction signal for the block of modulated symbols and allocating the peak correction signal to one or more sub-carriers dedicated to the peak correction signal in the sub-carrier mapping; and upon detecting no peak in the block of modulated symbols during the time-domain peak detection procedure, omitting said computing and said allocating.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication of parameters for estimating tone reservation (TR) subcarriers, based at least in part on energies of data symbols of a communication, having tone reservation applied for the communication. The UE may receive the communication having the tone reservation applied to the TR subcarriers. Numerous other aspects are described.

Apparatuses, methods, and systems for per carrier scaling of a cancellation pulse of a multi-carrier signal are disclosed. One method includes identifying a target PAPR (peak to average power ratio) for the multi-carrier signal, identifying a target EVM (error vector magnitude) for each of cj carriers of the multi-carrier signal, setting a scaling factor for each of the cj carrier to an initial value, or each carrier cj adjusting the scaling factor for the carrier cj until a measured EVM of the carrier cj satisfies the target EVM for the subcarrier cj while maintaining the PAPR target for the multi-carrier signal, and the cancellation pulse of the multi-carrier signal with the adjusted scaling factor for each of the cj carriers.

Aspects of the disclosure relate to techniques for peak-to-average power ratio (PAPR) reduction based on a tone reservation (TR) algorithm. For a TR algorithm, a suitable subset of tones from among a full set of tones in a given resource allocation are reserved for use as peak reduction tones (PRT). An apparatus, such as a wireless communication device, selects a set of PRTs based on a deterministic pseudo-random tone selection algorithm, such as quadratic sampling, cubic sampling, or Fibonacci-type sampling. The apparatus determines a PAPR reduction waveform for transmission on the PRTs and transmits a data waveform multiplexed with the PAPR reduction waveform on resources corresponding to the resource allocation. Other aspects, embodiments, and features are also claimed and described.

Methods, systems, and devices for wireless communications are described. To reduce peak-to-average power ratio (PAPR) associated with transmissions in a wireless communications system, a user equipment (UE) may implement tone reservation techniques. The UE may receive downlink control information from a base station that indicates a set of allocated resources that the UE is to use for the tone reservation. The UE may identify a first set of tones of the set of allocated resources for transmitting a data signal and a second set of tones of the set of allocated resources for transmitting a peak-reduction signal that reduces the peak power of the data signal. The UE may transmit the data signal and the peak-reduction signal based on the received downlink control information.