QBPA Interference Cancellation for MIMO Full-Duplex Isolation

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Solution Overview

Problem

Existing wireless communication systems face significant self-interference challenges, particularly in MIMO FD operations, due to the need for high Tx/Rx isolation and crosstalk between multiple antenna chains, which existing technologies have not adequately addressed.

Innovation Solution

A device and method for cancelling interference in multiple Quadrature Balanced Power Amplifiers (QBPAs) by generating and injecting cancellation signals at the fourth port to minimize leakage signals at the third port, using transfer functions to calculate optimal SIC signals for each chain, including nonlinear components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional interference cancellation techniques are used, then interference suppression is achieved, but system complexity and computational overhead increase significantly

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

Solution Approach 1:

The patent transforms the interference cancellation problem from the spatial domain to the frequency domain by applying Fourier transforms. This parameter transformation allows interference suppression to be achieved through simple frequency domain filtering operations rather than complex spatial processing, thereby reducing system complexity while maintaining effective interference suppression.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex mechanical signal processing operations with mathematical transformations in the frequency domain. By using Fourier transforms and frequency domain filtering, the system achieves interference cancellation through computational mathematics rather than complex physical signal processing mechanisms, reducing overall system complexity.

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

2Object-affected harmful factors

If advanced interference cancellation algorithms are implemented, then interference rejection improves, but processing time and computational resources increase

Engineering Contradiction:
Improveinterference rejectionVSAvoidprocessing time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent changes the processing domain from time/space to frequency domain, where interference cancellation operations can be performed more efficiently. The Fourier transform converts complex temporal signal processing into simpler frequency domain operations, reducing processing time while maintaining or improving interference rejection performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs periodic sampling and transformation operations in the frequency domain, allowing for efficient batch processing of interference cancellation. By periodically transforming signals between time and frequency domains and applying filtering operations, the system achieves rapid interference rejection without continuous complex processing.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP4133605B1Device and method for cancelling interference
Publication Date: 2026.05.20 HUAWEI TECH CO LTD
  • EP4133605B1 patent drawingFigure 1
  • EP4133605B1 patent drawingFigure 2
  • EP4133605B1 patent drawingFigure 3

AI summary

The present disclosure provides a device for cancelling interference of multiple QBPAs, wherein each QBPA comprises a first port for receiving a transmit input signal, a second port for transmitting a transmit signal and receiving a receive signal, a third port for providing a receive output signal, and a fourth port for receiving a cancellation input signal. The device is configured to: determine a cancellation input signal for each respective QBPA, wherein the cancellation input signal cancels a leakage signal at the third port of the respective QBPA, that is caused by the transmit input signal of the respective QBPA, one or more transmit input signals of one or more other QBPAs of the multiple QBPAs, and one or more cancellation input signals of one or more other QBPAs of the multiple QBPAs; and provide the determined cancellation input signal to the fourth port of the respective QBPA.