Harmonic Estimation and Cancellation in Wireless Signal Reception

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Solution Overview

Problem

Wireless communication networks face performance degradation due to harmonics, which can be active or passive, especially in multi-band, multi-carrier transmissions, leading to receiver desensitization and reduced signal quality.

Innovation Solution

An apparatus and method that transmit a first signal, detect and estimate harmonics caused by the transmission, and subtract the harmonic estimation from the received signal to improve receiver sensitivity and mitigate noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multi-band, multi-carrier transmissions are implemented in FDD deployments, then network capacity and coverage are improved, but harmonics are generated that degrade receiver performance

Engineering Contradiction:
Improvenetwork capacityVSAvoidharmonic interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful harmonic signal into a beneficial cancellation opportunity by estimating the harmonic based on the transmitted signal and subtracting it from the received signal. This transforms the harmful interference into a controlled subtraction operation that improves receiver sensitivity while maintaining multi-band, multi-carrier transmission capabilities.

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

Solution Approach 2:

The patent performs preliminary estimation of the harmonic signal before the actual reception and processing of the desired signal. By calculating the expected harmonic based on the transmitted signal characteristics in advance, the system prepares the cancellation component ready to remove the interference, thereby improving receiver performance without affecting the main transmission functionality.

Inventive Principle:
Principle #10Preliminary action

2Temperature

If transmitter power is increased to improve signal coverage, then coverage area is expanded, but harmonic distortion increases causing receiver desensitization

Engineering Contradiction:
Improvesignal coverageVSAvoidsignal quality
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent converts the harmful effect of increased harmonic distortion (caused by higher transmitter power) into a beneficial outcome by explicitly estimating and canceling the harmonic component. This allows the system to operate at higher power levels for improved coverage while maintaining signal quality through digital harmonic cancellation.

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

3Measurement precision

If receiver sensitivity is improved by filtering out harmonics, then signal-to-noise ratio is enhanced, but device complexity increases due to additional processing

Engineering Contradiction:
Improvereceiver sensitivityVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex physical filtering mechanisms with a digital signal processing approach. Instead of using additional hardware filters that would increase device complexity, the system uses mathematical estimation and subtraction operations to remove harmonics, achieving the same filtering effect with simpler digital processing.

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

Data Source

PatentEP4318955A1Mitigating harmonic when receiving a signal
Publication Date: 2024.02.07 NOKIA SOLUTIONS & NETWORKS OY
  • EP4318955A1 patent drawingFigure 1
  • EP4318955A1 patent drawingFigure 2A
  • EP4318955A1 patent drawingFigure 2B

AI summary

Disclosed is a method comprising transmitting a first signal, obtaining an indication of a harmonic, wherein the harmonic is caused by the transmission of the first signal, determining, based on the indication of the harmonic, an estimation of the harmonic, receiving a second signal, wherein the second signal comprises the harmonic, and subtracting the estimation of the harmonic from the second signal.