Full-Duplex Self-Interference Cancellation via Segmented Signal Processing

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Solution Overview

Problem

Existing full-duplex communication systems face challenges in effectively eliminating self-interference signals across all frequency bands, leading to varying noise levels and limited application scope due to frequency selectiveness in radio frequency elimination methods.

Innovation Solution

The method involves splitting a self-interference signal into multiple sub-signals, adjusting their amplitudes and phases to match a target signal, superposing these with received signals, and filtering using specific channels to isolate the wanted signal, ensuring effective interference cancellation across each frequency band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radio frequency elimination is used for self-interference processing, then elimination performance is improved on certain frequency bands, but elimination performance deteriorates on other frequency bands due to hardware frequency selectiveness

Engineering Contradiction:
Improveself-interference elimination performanceVSAvoidfrequency band coverage
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent divides the wideband self-interference signal into multiple narrowband signals through frequency domain segmentation. Each narrowband signal is processed separately through dedicated elimination channels, allowing optimized elimination performance for each frequency band while maintaining overall wideband coverage. This resolves the contradiction by applying segment-specific processing to achieve both high precision and broad adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements different elimination characteristics for different frequency bands by processing each narrowband signal through its own elimination channel. Each channel can be optimized for its specific frequency range, providing locally adapted elimination performance. This allows the system to achieve high elimination performance across all frequency bands simultaneously, resolving the frequency selectiveness limitation.

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If wideband self-interference signal is processed through radio frequency elimination, then entire bandwidth coverage is achieved, but noise levels vary greatly across different frequencies affecting application scope

Engineering Contradiction:
Improvebandwidth coverageVSAvoidsignal-to-noise ratio consistency
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent segments the wideband signal into multiple narrowband signals and processes each through dedicated elimination channels. This segmentation allows each channel to maintain consistent noise characteristics within its frequency range, preventing the extreme noise variations that occur in wideband processing. The result is uniform signal-to-noise ratio across the entire bandwidth while maintaining full frequency coverage.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If self-interference signal is not fully eliminated on certain frequency bands, then system complexity is reduced, but remaining interference affects full-duplex application scope

Engineering Contradiction:
Improveelimination processing complexityVSAvoidfull-duplex application scope
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent divides the complex wideband elimination problem into multiple simpler narrowband elimination tasks. Each narrowband channel requires less complex processing, but the combination of multiple channels achieves comprehensive elimination across the entire bandwidth. This segmented approach makes full-duplex feasible across wide bandwidths without requiring excessively complex single-channel processing.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for precise filtering of self-interference signals on each frequency band, resulting in a complete wanted signal with improved precision and reduced noise, enhancing the application scope of full-duplex technology.

Implementation Method 1

adjusting amplitudes and phases of sub self-interference signals to obtain adjusted sub-signals, where a phase of the signal of a first frequency range of the adjusted sub-signals is reverse to a phase of the signal of the first frequency range of the second self-interference signal

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP2911308B1Method and device for signal interference processing
Publication Date: 2019.05.22 HUAWEI TECH CO LTD
  • EP2911308B1 patent drawingFigure 1~2
  • EP2911308B1 patent drawingFigure 3
  • EP2911308B1 patent drawingFigure 4

AI summary

Embodiments of the present invention relate to a method and an apparatus for processing signal interference, including: splitting a first self-interference signal into at least two same sub self-interference signals, adjusting amplitudes and phases of the sub self-interference signals to obtain adjusted sub-signals, superposing the adjusted sub-signals and received signals, to obtain superposed sub-signals, filtering the superposed sub-signals by using filters of corresponding channels, to obtain wanted sub-signals, and merging each of the wanted sub-signals to obtain a complete wanted signal. Because received signals are separately filtered by using n different channels, it can be implemented that a self-interference signal can be effectively filtered out on each frequency band.