Radio Transceiver Interference Suppression Without Diplexers

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Solution Overview

Problem

Existing radio transceiver devices face challenges in suppressing interference due to cross-modulation between transmitted and received signals, leading to performance degradation and increased costs due to the use of diplexers, which are expensive and require multiple variants for different frequency bands.

Innovation Solution

A method and control device that utilize a notch filter to replace the diplexer, combined with a control device and computer program to estimate and compensate for interference distortion, effectively suppressing cross-modulation using a control device and computer program to estimate and compensate for interference distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a diplexer filter is used to prevent transmitted signal leakage into the receiver, then interference suppression is improved, but device cost and complexity increase

Engineering Contradiction:
Improveinterference suppressionVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts and removes the harmful transmitted signal component from the received signal using digital signal processing. Instead of using a physical diplexer filter to block the transmitted signal, the invention digitally identifies and subtracts the transmitted signal replica from the composite received signal, effectively extracting and removing only the harmful interference component.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/physical diplexer filter system with a digital signal processing system. Instead of relying on physical filtering components that require precise frequency matching and physical isolation, the invention uses mathematical operations (correlation, subtraction) to achieve signal separation, substituting physical mechanisms with computational methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If multiple diplexer variants are manufactured for different frequency bands, then frequency band adaptability is improved, but manufacturing cost and warehousing requirements increase

Engineering Contradiction:
Improvefrequency band adaptabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent creates a universal interference suppression algorithm that can operate across multiple frequency bands without requiring hardware changes. The digital signal processing approach uses frequency indexing and correlation techniques that are band-agnostic, allowing the same device architecture to serve multiple frequency bands (e.g., 70cm, 23cm, 6cm bands) with a single implementation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the approach from physical parameter customization (different diplexer designs for different frequencies) to digital parameter adjustment (frequency indexes and correlation parameters). By storing frequency-specific indexes in a lookup table and adjusting digital parameters rather than physical components, the system achieves frequency band adaptability without manufacturing multiple hardware variants.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a diplexer is used to prevent signal leakage, then receiver saturation is prevented, but space requirements and component cost increase

Engineering Contradiction:
Improvereceiver saturation preventionVSAvoidspace requirements
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent creates a digital replica or copy of the transmitted signal and uses this copy to subtract the interference from the received signal. By generating and utilizing a transmitted signal replica with known characteristics (frequency, modulation, power level), the system can accurately identify and remove the interfering component without requiring physical isolation components like diplexers.

Inventive Principle:
Principle #26Copying

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 reduces interference, lowers production and warehousing costs, and improves signal quality by efficiently suppressing cross-modulation without the need for multiple diplexer variants.

Implementation Method 1

A method and control device that utilize a notch filter to replace the diplexer

Methodology Applied
Scientific EffectFrequency filtering: Filter (electronic)

Implementation Method 2

combined with a control device and computer program to estimate and compensate for interference distortion

Methodology Applied
Scientific EffectSignal processing:

Data Source

PatentEP3440780B1Interference supression in a radio transceiver device
Publication Date: 2025.10.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3440780B1 patent drawingFigure 1~2
  • EP3440780B1 patent drawingFigure 3(a)~3(b)
  • EP3440780B1 patent drawingFigure 4~5

AI summary

There is provided mechanisms performed by a control device for suppressing interference in a received reception signal in a radio transceiver device. The radio transceiver device is configured to receive the reception signal as a radio reception signal and to generate a radio transmission signal. The radio transmission signal and the radio reception signal occupy at least partly non-overlapping frequency bands. A method comprises obtaining a transmission reference signal based on the radio transmission signal. The method comprises estimating an interference distortion component signal based on the transmission reference signal and on a model of nonlinearity in a radio circuit of the radio transceiver device. The method comprises suppressing interference in the reception signal by combining the reception signal with the distortion component signal.