Near-Field Interference Cancellation for Full-Duplex Systems
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Solution Overview
Problem
Existing wireless full-duplex systems face challenges in effectively canceling near-field reflected self-interference signals, which can cause saturation in the receiver and degrade signal quality due to their strong power relative to desired signals.
Innovation Solution
The proposed solution involves an interference cancellation apparatus and method that includes a splitter, main receive antenna, first and second main-path interference cancellers, and a near-field interference canceller. The apparatus configures a reference signal from a transmit signal to perform main-path interference cancellation and then uses this signal to process near-field interference cancellation, enhancing the correlation between self-interference signals received by parallel main and reference receive antennas to effectively cancel near-field reflected self-interference components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wireless full-duplex technology is implemented to simultaneously perform receiving and sending operations on the same radio channel, then spectral efficiency is improved (doubled compared to FDD or TDD), but strong self-interference from transmit signal on receive signal occurs causing receiver saturation and degraded signal quality
Solution Approach 1:
The patent segments the interference cancellation process into multiple stages: analog interference cancellation at the radio frequency front-end, digital interference cancellation at the baseband, and specifically near-field interference cancellation as a separate stage. This multi-stage segmentation allows each stage to address specific types of interference components systematically, resolving the self-interference problem while maintaining full-duplex spectral efficiency
Solution Approach 2:
The patent introduces a near-field interference canceller as an intermediary component between the main receive antenna and the baseband processor. This intermediary unit specifically targets and cancels near-field reflected self-interference signals before they reach the baseband processing stage, preventing receiver saturation while preserving the desired signal
2Device complexity
If near-field reflected self-interference signals are not effectively canceled, then the system structure remains simple, but receiver saturation occurs and signal quality degrades
Solution Approach 1:
The patent applies preliminary action by performing near-field interference cancellation before baseband processing. The near-field interference canceller processes the received signal in advance to remove near-field reflected self-interference components, preventing these strong interference signals from causing receiver saturation and ensuring high signal quality in subsequent processing stages
Solution Approach 2:
The patent replaces traditional hardware-based interference suppression mechanisms with a signal processing-based near-field interference canceller. This software/digital approach achieves effective near-field interference cancellation without requiring complex hardware modifications, maintaining system structure simplicity while improving signal quality
Data Source
AI summary
Embodiments of the present invention provide an interference cancellation apparatus. The apparatus includes: a splitter, configured to send an acquired reference signal to a first and second main-path interference canceller; a main receive antenna, configured to send an acquired first receive signal to the first main-path interference canceller; the first main-path interference canceller, configured to perform first main-path interference cancellation processing on the first receive signal according to the reference signal, to generate a first processing signal; a reference receive antenna, configured to acquire and send a second receive signal to the second main-path interference canceller; the second main-path interference canceller, configured to perform second main-path interference cancellation processing on the second receive signal according to the reference signal, to generate a second processing signal; and a near-field interference canceller, configured to perform near-field interference cancellation processing on the first processing signal according to the second processing signal.