Iterative Interference Cancellation for Digital Signal Reception

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Solution Overview

Problem

Current digital communication systems fail to effectively extract useful information from interfering components, treating them as additional noise, which reduces the probability of successful signal detection and increases bit errors due to non-linear distortion and interference.

Innovation Solution

A receiver design that estimates and iteratively cancels individual interfering components using estimated received constellation centroids and respective scaling factors, rather than treating interference as noise, thereby improving error rates and power efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If interfering components are treated as additional noise, then the receiver design is simple, but the probability of successful signal detection decreases and bit errors increase

Engineering Contradiction:
Improveprobability of successful signal detectionVSAvoidreceiver design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the received signal into useful signal components and interfering components by estimating received constellation centroids for different signal hypotheses. This segmentation allows the receiver to separately process and evaluate each component, improving detection reliability without requiring overly complex processing of the entire signal as a single entity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent converts the harmful interfering components into beneficial information by estimating their characteristics through received constellation centroid analysis. Instead of simply treating interference as noise to be rejected, the method extracts useful information about the interfering signals to improve overall detection accuracy through iterative cancellation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Use of energy by moving object

If interfering components are treated as additional noise, then the processing is simple, but power efficiency decreases

Engineering Contradiction:
Improvepower efficiencyVSAvoidprocessing complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent performs preliminary estimation of received constellation centroids and interfering component characteristics before the main detection and decoding processes. This preliminary action allows subsequent processing stages to work with cleaner, pre-processed signals, reducing the overall computational burden and improving power efficiency throughout the reception chain.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements iterative interference cancellation where the receiver continuously refines its estimate of interfering components based on detection results, then uses these refined estimates to improve subsequent detections. This feedback loop progressively improves power efficiency by reducing the energy needed for retransmissions and error correction.

Inventive Principle:
Principle #23Feedback

3Reliability

If individual interfering components are estimated and cancelled, then interference cancellation gains are maximized, but the processing complexity increases

Engineering Contradiction:
Improveerror ratesVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by estimating received constellation centroids specifically for different signal hypotheses rather than treating the entire signal uniformly. This localized approach focuses computational resources on the most relevant signal components, achieving better error rate performance without proportionally increasing overall processing complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements iterative interference cancellation where the processing is performed to the extent necessary to achieve detection thresholds. The iteration stops when sufficient cancellation is achieved, avoiding excessive processing while still obtaining meaningful interference cancellation gains for improved error rates.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3172879B1Method for receiving a digital signal in a digital communication system
Publication Date: 2018.10.17 DEUTSCHES ZENTRUM FÜR LUFT UND RAUMFAHRT E V
  • EP3172879B1 patent drawingFigure 1
  • EP3172879B1 patent drawingFigure 2a
  • EP3172879B1 patent drawingFigure 2b

AI summary

Method for receiving a digital signal in a digital communication system The method for receiving a digital signal in a digital communication systems with linear and/or non-linear distortion comprises receiving the digital signal transmitted via a transmission channel, wherein the received signal including an interfering component, and processing the received signal for providing adjacent channel interference (ACI) cancellation, including intermodulation interference (IMI) and residual inter-symbol interference (ISI) cancellation, wherein processing comprises iteratively performing both estimation of the interfering component and subtraction of the estimated interfering component from the received signal.