Circular Convolution PAPR Reduction in Wireless Transmitters

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Solution Overview

Problem

Current wireless communication standards, such as OFDM and OFDMA, suffer from high peak-to-average power ratio (PAPR), leading to inefficient power amplification, increased infrastructure costs, and reduced transmission range due to the need for power back-off to prevent signal distortion.

Innovation Solution

A communication system that employs a circular convolution module, an M-point DFT module, and an N-point IDFT module to process symbols, along with circular de-convolution at the receiver, utilizing mathematical distributions to minimize PAPR by spreading symbols in the time domain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power back-off is applied to avoid signal distortion, then signal linearity is improved, but transmission range and power efficiency deteriorate

Engineering Contradiction:

Improvesignal linearityVSAvoidpower efficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by modifying the signal processing parameters through circular convolution with preset values and DFT/IDFT operations. This transforms the signal characteristics to reduce peak power levels while maintaining average power, thereby reducing PAPR and allowing the power amplifier to operate more efficiently without requiring excessive power back-off.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If power back-off is applied to avoid signal distortion, then signal linearity is improved, but transmission range deteriorates

Engineering Contradiction:

Improvesignal linearityVSAvoidtransmission range

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent changes signal parameters through circular convolution and transform operations to reduce peak power levels. This enables the transmitter to operate at higher average power levels without causing signal distortion, thereby extending transmission range while maintaining signal linearity.

Inventive Principle:

Principle #35Parameter changes

3Power

If amplitude clipping is applied to reduce PAPR, then PAPR is improved, but in-band and out-of-band distortions increase

Engineering Contradiction:

ImprovePAPRVSAvoiddistortions

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the mechanical/amplitude-based clipping approach with a mathematical transformation approach using circular convolution and DFT/IDFT operations. This substitution eliminates the need for aggressive amplitude clipping while achieving PAPR reduction through signal spreading and transformation, thereby avoiding the associated in-band and out-of-band distortions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10149240B2Communication system and method for achieving low peak-to-average power ratio

Publication Date: 2018.12.04 TEJAS NETWORKS LTD

AI summary

The present disclosure pertains to communication systems and methods for achieving low peak to average power ratio (PAPR) for transmitted symbols of wireless devices. In an aspect, the present disclosure relates to a transmitter of a communication system, wherein the transmitter includes a circular convolution module that is configured to circularly convolve a preset number of values with a group of M symbols from a total number of symbols, an M-point DFT module that is configured to process output of the circular convolution to generate a first set of discrete Fourier transform (DFT) samples, and an N-point IDFT module that is configured to process the first set of DFT samples to obtain a first set of inverse discrete Fourier transform (IDFT) samples for onward transmission to a receiver.