According to one general aspect, an apparatus may include a pre-transmission circuit configured to encode a data signal for communication. The apparatus may include a peak-to-average-power ratio (PAPR) controlling circuit configured to set a power level for a level-adjusted data signal. In some embodiments, the PAPR circuit may be configured to set the power level by employing a multi-loop, multi-phase technique, wherein an inner loop employs multiple phases to constrain the PAPR and reduce at least one power-related error condition, and wherein an outer loop updates the power level. The apparatus may include a transmitter circuit configured to transmit the level-adjusted data signal.

In embodiments of the presently described subject matter, two efficient PAPR reduction methods for OFDM signals based upon the principle of tone reservation and building upon the clipping noise analysis presented in “Analysis of clipping noise and tonereservation algorithms for peak reduction in OFDM systems,” L. Wang and C. Tellambura, IEEE Trans. Veh. Technol., vol. 57, pp. 1675-1694, May 2008 are provided, each comprising two stages. The first stage is performed offline to prepare a set of cancelation signals based on the settings of the OFDM system. In particular, these cancellation signals are constructed to cancel signals at different levels of maximum instantaneous power that are above a predefined threshold. The second stage is performed online and in an iterative manner to reduce the peaks of OFDM symbols by using the cancellation signals constructed in the first stage.

According to an aspect of the present invention, there is provided a method for providing additional bandwidth to receivers that can decode a higher modulation comprising trading a peak-to-average power ratio (PAPR) reduction induced constellation noise of all or a subset of in-band on-channel (I BOC) carriers within an orthogonal frequency division multiplexing (ODFM) waveform with data carrying superposition modulation.

An apparatus, method and computer program is described comprising: receiving a first signal comprising one or more carrier signals comprising a plurality of resource blocks, wherein each resource block is assigned to a unique frequency and time slot of the respective carrier signal; generating a clipping pulse by modifying said first signal; converting the clipping pulse signal into a plurality of narrowband signals, wherein each narrowband signal is a frequency slice of the clipping pulse signal; modifying the plurality of narrowband signals to generate a plurality of modified narrowband signals, wherein said modifying is controlled based on filter weights that define a level of noise to be added to the respective narrowband signals in accordance with a desired error vector magnitude distribution or clipping noise distribution.

A computer-implemented method for reducing crest factor by an electronic device includes: receiving a plurality of first samples of a first input signal. The plurality of first samples are generated at a first sampling rate. A first peak detection is performed based on the plurality of first samples to generate a plurality of first peak detection output samples. A plurality of first windowing input samples are generated at a second sampling rate by downsampling the plurality of first peak detection output samples. A plurality of first windowing output samples are generated based on the plurality of first windowing input samples. A plurality of first peak reduction samples are generated at the first sampling rate by upsampling the plurality of first windowing output samples. A first output signal is generated based on the plurality of first samples and the plurality of first peak reduction samples.

Systems and methods for ultra-wideband Crest Factor Reduction (CFR) are provided. In some embodiments, a method performed by a wireless node for performing CFR includes performing a first CFR step on a plurality of input signals at a first sampling rate with joint peak detection and band-specific noise shaping; and performing a second CFR step on the resulting plurality of input signals at a second sampling rate with joint peak detection and joint noise shaping where the second sampling rate is higher than the first sampling rate. In this way, Peak-to-Average Power Ratio (PAPR) reduction may be increased while the computational complexity is reduced.

A dynamic configuration of crest factor reduction in a licensed assisted access radio system. A processing device comprises a detecting block, a clipping pulse generator, a first storage block, a selecting block, a full clipping block and a simplified clipping block. The detecting block performs a listen-before-talk (LBT) procedure on a plurality of carriers in parallel and generates a trigger signal in response to LBT success on one or more carriers. The clipping pulse generator generates, for the carrier(s) with LBT success, a clipping pulse within a time period from the receipt of the trigger signal to the start of user traffic transmission. The first storage block stores the clipping pulse for use by the full clipping block. The selecting block selects the full clipping block when there is user traffic on the carrier(s) and selects the simplified clipping block when there is no user traffic on the carrier(s).

According to an aspect of the present invention, there is provided a method for providing additional bandwidth to receivers that can decode a higher modulation comprising trading a peak-to-average power ratio (PAPR) reduction induced constellation noise of all or a subset of in-band on-channel (IBOC) carriers within an orthogonal frequency division multiplexing (ODFM) waveform with data carrying superposition modulation.

A user equipment (UE) may multiplex peak suppression information message (PSIM) on a physical uplink shared channel (PUSCH) with data for efficient implementation of PSIMs for peak to average power ratio (PAPR) reduction. A UE may clip peaks from a signal to be transmitted and capture information of the clipped peaks into a PSIM. The UE may then multiplex the PSIM on the PUSCH such that a receiving device (for example, a base station) may receive the signal and reconstruct the signal (for example, PUSCH data) using the PSIM. According to some aspects, each PUSCH symbol may include a PSIM for a previous PUSCH symbol (for example, such that causality is preserved if multiplexing PSIM and data for each PUSCH symbol). Various aspects of the techniques described herein may further provide for PSIM positioning in frequency, PSIM modulation, PSIM channel coding, PSIM multiple-input multiple-output (MIMO) configurations, among other examples.

A dynamic configuration of crest factor reduction in a licensed assisted access radio system. A processing device comprises a detecting block, a clipping pulse generator, a first storage block, a selecting block, a full clipping block and a simplified clipping block. The detecting block performs a listen-before-talk (LBT) procedure on a plurality of carriers in parallel and generates a trigger signal in response to LBT success on one or more carriers. The clipping pulse generator generates, for the carrier(s) with LBT success, a clipping pulse within a time period from the receipt of the trigger signal to the start of user traffic transmission. The first storage block stores the clipping pulse for use by the full clipping block. The selecting block selects the full clipping block when there is user traffic on the carrier(s) and selects the simplified clipping block when there is no user traffic on the carrier(s).