Non-linear Impairments Correction Precoder Configuration

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in addressing radio frequency (RF) link impairments due to high back-off requirements, leading to low power efficiency and sub-optimal performance in managing both linear and non-linear distortions across the entire channel.

Innovation Solution

An enhanced non-linear impairments correction precoder configuration that combines predistortion and beamforming, utilizing feedback from receiver devices to optimize the total channel capacity with reduced back-off, thereby improving Error Vector Magnitude (EVM) and capacity while maintaining the required Adjacent Channel Leakage Ratio (ACLR).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high back-off is used to maintain ACLR and signal quality, then signal quality and ACLR are improved, but power efficiency of the power amplifier deteriorates

Engineering Contradiction:
Improvesignal qualityVSAvoidpower efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent combines linear precoding and digital predistortion into a unified joint optimization framework that simultaneously addresses both linear channel exploitation and non-linear distortion correction, allowing the system to achieve better signal quality and ACLR performance without requiring high back-off, thus improving power efficiency

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the operational parameters by optimizing the back-off level through joint design of linear and non-linear processing, finding the optimal balance point that maintains signal quality and ACLR requirements while maximizing power amplifier efficiency

Inventive Principle:
Principle #35Parameter changes

2Reliability

If independent digital blocks (linear precoder and digital predistorter) are used, then linear and non-linear distortions are addressed separately, but system complexity increases and performance is sub-optimal

Engineering Contradiction:
Improvedistortion correctionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the linear precoder and digital predistorter into a joint optimization framework that handles both linear and non-linear distortions in a unified manner, reducing system complexity while achieving optimal performance by exploiting the total channel capacity rather than treating components independently

Inventive Principle:
Principle #5Merging (Combining)

3Object-generated harmful factors

If high back-off is applied to maintain ACLR, then adjacent channel power leakage is reduced, but emission power and productivity decrease

Engineering Contradiction:
Improveadjacent channel power leakageVSAvoidemission power
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The patent optimizes the back-off parameter through joint design, achieving the required ACLR performance with significantly lower back-off levels, thereby maintaining adjacent channel protection while maximizing emission power and system productivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent recovers the power efficiency that would otherwise be lost to high back-off requirements by using joint optimization to achieve the same ACLR performance with lower back-off, effectively recovering the discarded power for productive use

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP3472990B1Wireless communication impairments correction
Publication Date: 2020.03.25 QUALCOMM INC
  • EP3472990B1 patent drawingFigure 1
  • EP3472990B1 patent drawingFigure 2
  • EP3472990B1 patent drawingFigure 3

AI summary

Systems and methods for providing wireless communication impairment correction using non-linear iterative precoding by a transmitter device are disclosed. The transmitter may exploit the non-linear transmit indications, and perform digital non-linear multiple input multiple output (MIMO) precoding of a transmit signal to improve the error vector magnitude (EVM) at the intended receiver device and/or reduce the adjacent channel leakage ratio (ACLR) at the unintended receiver devices. The non- linear transmit indications may comprise amplitude modulation to amplitude modulation (AM-AM) and amplitude modulation to phase modulation (AM-PM) indications. In operation, the non-linear transmit indications may be received from the intended receiver devices or may be measured by the transmitter device.