Configurable Hybrid Self-Interference Cancellation for Full-Duplex Transceivers
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Solution Overview
Problem
Full-duplex wireless communication systems face challenges due to self-interference, which existing solutions often fail to address effectively without increasing complexity or incurring significant loss, and lack flexibility across different operational modes and environments.
Innovation Solution
A configurable hybrid self-interference cancellation system that combines analog and digital cancellation methods, using a primary analog self-interference canceller, secondary analog self-interference canceller, digital self-interference canceller, and a controller to adaptively mitigate self-interference by sampling and processing both analog and digital transmit signals, allowing for simultaneous and parallel cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional self-interference cancellation solutions are used, then self-interference is partially reduced, but system complexity increases significantly
Solution Approach 1:
The self-interference cancellation is divided into two distinct stages: analog cancellation that processes the transmit signal before transmission, and digital cancellation that processes the received signal after reception. This segmentation allows each stage to handle specific aspects of interference reduction with optimized complexity, avoiding the need for a single overly complex system.
Solution Approach 2:
The system dynamically switches between different cancellation modes (analog-only, digital-only, or hybrid) based on operating conditions such as MIMO configuration, signal environment, and performance requirements. This dynamic adaptability allows the system to optimize the balance between self-interference reduction and complexity for each specific scenario.
2Object-affected harmful factors
If high-performance self-interference cancellation is implemented, then cancellation effectiveness improves, but adaptability to changing operational modes deteriorates
Solution Approach 1:
The hybrid cancellation system is designed to universally handle multiple operational modes including 4×4 MIMO, 1×4 SIMO, and various antenna configurations. The analog and digital cancellation components work together in a unified framework that can be configured for different scenarios, allowing the same system architecture to provide high-performance cancellation across diverse operational contexts.
Solution Approach 2:
The system employs dynamic configuration capabilities that allow it to adapt its cancellation strategy based on real-time operational parameters. The controller can adjust the balance between analog and digital cancellation, switch between different antenna configurations, and modify processing parameters to maintain optimal performance across changing conditions.
3Productivity
If analog self-interference cancellation is used, then cancellation efficiency is improved, but loss in signal quality increases
Solution Approach 1:
The cancellation process is segmented into analog and digital domains, with the analog stage handling the bulk of interference reduction efficiently, and the digital stage providing fine-tuned correction. This segmentation allows the system to leverage the high efficiency of analog processing while using digital processing to minimize signal quality degradation through precise, adaptive correction.
Solution Approach 2:
The digital cancellation component acts as an intermediary that refines the output of analog cancellation. It processes the residual interference and signal components, applying precise corrections that compensate for any signal quality loss introduced by the analog stage, thereby maintaining overall signal integrity while preserving cancellation efficiency.
Data Source
AI summary
A system for self-interference cancellation includes a frequency downconverter that decomposes a sampled RF transmit signal into an in-phase transmit signal and a quadrature transmit signal; a first analog vector modulator that scales the transmit signals to generate first scaled transmit signals; a second analog vector modulator that scales delayed transmit signals to generate second scaled transmit signals; a frequency upconverter that recomposes the scaled transmit signals into an RF self-interference cancellation signal; and a receive coupler that that combines the RF self-interference cancellation signal with a RF receive signal to reduce self-interference.