Interference Cancellation Circuit for Impulse Noise in Vehicles

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Solution Overview

Problem

Existing wireless and radio frequency communication systems face challenges in accurately and efficiently receiving signals due to impulse noise from sources like vehicle engines, which is not effectively removed by ordinary linear filtering, impairing AM/FM radio signal reception in electric and hybrid vehicles.

Innovation Solution

An interference cancellation system utilizing an electronic control unit with filter, signal detection, and synthesis circuitry to estimate and subtract impulse noise based on timing, amplitude, phase, and pulse shape parameters, enhancing the signal-to-noise ratio by amplifying and isolating the filtered signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If ordinary linear filtering is used to remove impulse noise, then filtering simplicity is maintained, but the wanted signal is significantly degraded along with the noise

Engineering Contradiction:
Improvefiltering simplicityVSAvoidsignal reception accuracy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the impulse noise removal process into distinct stages: detection of impulse noise characteristics, estimation of noise parameters (amplitude, duration, frequency), and synthesis of cancellation signals. This segmentation allows targeted processing of noise components without affecting the wanted signal.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary cancellation signal that is synthesized to match the characteristics of the detected impulse noise. This cancellation signal acts as a mediator that, when subtracted from the received signal, removes the impulse noise while preserving the wanted signal components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If impulse noise cancellation is implemented using the disclosed system, then signal-to-noise ratio is improved, but device complexity increases

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system employs self-service mechanisms where the impulse noise detection and characterization processes utilize the received signal itself to generate the cancellation parameters. The synthesis circuitry automatically adapts to varying noise characteristics without requiring external calibration or manual intervention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent dynamically changes key parameters of the cancellation signal including amplitude, duration, frequency, and phase based on real-time detection of impulse noise characteristics. This parameter adaptation allows the system to effectively cancel varying noise patterns while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If impulse noise is detected and characterized in real-time, then noise cancellation accuracy is improved, but processing time increases

Engineering Contradiction:
Improvenoise characterization accuracyVSAvoidprocessing delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by continuously monitoring and pre-characterizing the impulse noise properties during periods when noise patterns are stable. This allows the synthesis circuitry to quickly generate cancellation signals when new impulse noise events occur, reducing the effective processing delay.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies partial processing by focusing detection and characterization efforts only on the impulse noise components rather than analyzing the entire signal spectrum. This selective approach maintains high measurement precision for noise parameters while minimizing overall processing time and computational load.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3754856B1Systems and methods involving interference cancellation
Publication Date: 2023.08.30 NXP BV
  • EP3754856B1 patent drawingFigure 1A
  • EP3754856B1 patent drawingFigure 1B
  • EP3754856B1 patent drawingFigure 2

AI summary

Interference cancellation is provided, according to certain aspects, by a filter, a signal detection circuit, synthesis circuitry and signal-generation circuitry. The filter is used to filter an incoming signal having an associated signal-to-noise metric and to output therefrom a filtered signal having an interference attribute of the incoming signal by amplification and/or isolation. The signal detection circuit is used to detect the interference attribute in the filtered signal. The synthesis circuitry is used to synthesize interference in the incoming signal based on the interference attribute. The signal-generation circuitry is used to generate, in response to the synthesized interference in the incoming signal, a filtered version of the incoming signal which provides an improved signal-to-noise metric.