Self-Interference Canceller Tuning for Full-Duplex Transceivers
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Solution Overview
Problem
Full-duplex wireless communication systems face challenges due to self-interference, as they cannot effectively adapt to changing interference characteristics and component drifts, limiting their ability to maintain high self-interference cancellation performance over time.
Innovation Solution
A system and method for dynamic tuning of self-interference cancellers, incorporating a tuning circuit that controls parameters of both analog and digital self-interference cancellers, allowing for simultaneous and parallel cancellation of interference, using digital and analog circuitry with adaptive components like tunable filters, scalers, and delayers to adjust for changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional half-duplex communication systems are used, then self-interference is avoided, but spectral efficiency is limited
Solution Approach 1:
The patent converts the harmful self-interference signal into a beneficial cancellation reference by capturing a portion of the transmit signal and processing it through analog and digital cancellation circuits to generate an inverted version that subtracts from the received signal, thereby eliminating the harmful interference while enabling full-duplex operation
Solution Approach 2:
The patent segments the self-interference cancellation process into distinct analog and digital stages, with the analog canceller handling high-power RF interference and the digital canceller processing lower-power residual interference, allowing each segment to be optimized independently for its specific operating conditions
2Reliability
If fixed self-interference cancellation parameters are used, then device complexity is reduced, but cancellation performance degrades under varying conditions
Solution Approach 1:
The patent implements dynamic tuning mechanisms that automatically adjust analog canceller parameters (such as delay and attenuation) and digital canceller coefficients in response to changing operating conditions, ensuring optimal cancellation performance across varying frequencies, powers, and environmental conditions without manual intervention
Solution Approach 2:
The patent employs feedback loops that continuously monitor the effectiveness of self-interference cancellation and automatically adjust cancellation parameters to maintain optimal performance, with the system detecting residual interference levels and modifying analog/digital canceller settings accordingly
3Measurement precision
If frequent recalibration is performed, then cancellation accuracy is maintained, but loss of time increases
Solution Approach 1:
The patent implements periodic recalibration cycles that balance accuracy maintenance with operational continuity, performing full calibration sequences at intervals based on usage patterns and environmental stability, rather than continuously or on fixed schedules, thereby maintaining precision while minimizing time loss
Data Source
AI summary
A system for self-interference canceller tuning includes a transmit coupler that creates a sampled analog transmit signal; an analog self-interference canceller that transforms the sampled analog transmit signal to an analog self-interference cancellation signal according to a set of tuning parameters, the set of tuning parameters comprising complex weights for a set of taps of the analog self-interference canceller; a tuning circuit that calculates the set of tuning parameters, and applies the set of tuning parameters to the analog self-interference canceller based on component calibration data of the analog self-interference canceller; and a receive coupler that combines the analog self-interference cancellation signal with the analog receive signal to reduce self-interference in the analog receive signal.