SC-FDMA Signal Processing for OFDM PAPR Reduction

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Solution Overview

Problem

Orthogonal Frequency Division Multiplexing (OFDM) systems face challenges with high peak-to-average power ratio (PAPR), leading to signal distortion and decreased demodulation performance, particularly in high-frequency bands of next-generation communication systems like 5G, where efficient power amplification is crucial.

Innovation Solution

A data processing method that separates the real and imaginary parts of a transmit signal, performs phase rotation, and generates Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols to reduce PAPR, thereby improving link quality and system performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If OFDM technology is used to achieve advantages in anti-multipath interference and MIMO compatibility, then system functionality is improved, but peak-to-average power ratio increases causing signal distortion and decreased demodulation performance

Engineering Contradiction:
Improveanti-multipath interference capabilityVSAvoidsignal distortion
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the complex-valued symbol sequence by separating real parts and imaginary parts into two independent sequences. This segmentation allows independent processing of each part through DFT and IFFT operations, transforming the high-PAPR OFDM signal into a lower-PAPR signal while preserving the original signal's information content and anti-multipath interference capabilities

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the signal structure parameters by transitioning from a conventional OFDM complex signal to a SC-FDMA real signal. By modifying the signal generation process to separate and independently process real and imaginary parts, the PAPR parameter is reduced while maintaining the essential communication functions and frequency diversity benefits

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If transmit power is reduced to lower EVM, then signal distortion is decreased, but demodulation performance at the receive end deteriorates

Engineering Contradiction:
Improveerror vector magnitudeVSAvoiddemodulation performance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the fundamental signal structure from OFDM to SC-FDMA by separating real and imaginary parts and applying DFT preprocessing. This parameter change reduces the peak-to-average power ratio, allowing the power amplifier to operate in a more linear region, thereby reducing EVM without requiring transmit power backoff and maintaining demodulation performance

Inventive Principle:
Principle #35Parameter changes

3Productivity

If high frequency bands are used to increase data rates, then communication capacity is improved, but PAPR requirements become stricter due to decreased PA efficiency

Engineering Contradiction:
Improvedata rateVSAvoidPAPR
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the signal modulation approach by implementing SC-FDMA with separate processing of real and imaginary parts. This parameter change significantly reduces the PAPR of the transmit signal, making it suitable for high-frequency band operations where power amplifier efficiency is critical, thereby enabling high data rate communication without compromising signal quality

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3496368B1Data processing method, apparatus, and system
Publication Date: 2021.09.01 HUAWEI TECH CO LTD
  • EP3496368B1 patent drawingFigure 1~3(b)
  • EP3496368B1 patent drawingFigure 4~5
  • EP3496368B1 patent drawingFigure 6A~6B

AI summary

This application relates to the field of wireless communications technologies, and in particular, to a data processing method, apparatus, and system. This application provides a data processing method. A data sending device modulates a to-be-transmitted bit sequence, splits a real part and an imaginary part of a complex-valued symbol that is obtained through the modulation into two symbols to form a symbol sequence, performs phase rotation of symbols in the symbol sequence, and performs sending by using a single carrier frequency division multiple access (Single Carrier Frequency Division Multiple Access, SC-FDMA) symbol. This application is intended to reduce a peak-to-average power ratio (Peak-to-Average Power Ratio, PAPR) of a transmit signal of an orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) system by splitting a real part and an imaginary part of a to-be-transmitted signal, and improve link quality of an entire transmission system.