Transceiver Self-Interference Cancellation via Analog and Digital Filtering
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Solution Overview
Problem
Current full-duplex wireless communication systems face challenges in achieving practical self-interference cancellation, with existing techniques either being impractical for real-world implementation or failing to meet the requirements for efficient spectrum reuse due to limitations in antenna placement, noise canceling chips, and phase noise issues.
Innovation Solution
A transceiver architecture that performs sequential self-interference cancellation in both the analog RF domain and digital domain, using an antenna arrangement with an analog domain filter and an auxiliary transmitter to generate interference cancellation signals, allowing for low or vanishing self-interference levels and enabling efficient frequency and time resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If experimental testbeds demonstrate almost perfect self-interference cancellation levels, then self-interference cancellation performance is improved, but practical implementation feasibility deteriorates
Solution Approach 1:
The patent segments the self-interference cancellation process into three distinct domains: RF domain cancellation using passive/active elements, hybrid domain cancellation combining RF and digital processing, and digital domain cancellation using signal processing algorithms. This segmentation allows each domain to address specific aspects of self-interference, making the overall system practical for implementation while achieving high cancellation levels.
Solution Approach 2:
The patent employs parameter changes by adjusting cancellation coefficients, filter characteristics, and signal processing parameters across different domains. The system dynamically modifies these parameters to optimize performance for varying channel conditions, maintaining practical implementation while achieving superior cancellation levels.
2Measurement precision
If directional antennas and physical separation are used for RF attenuation cancellation, then passive cancellation results are improved for line-of-sight, but vulnerability to multipath wireless channel components increases
Solution Approach 1:
The patent creates a composite cancellation system that combines multiple cancellation techniques across different domains (RF passive elements, active signal injection, digital processing). This composite approach leverages the strengths of each domain while compensating for their individual weaknesses, particularly protecting against multipath effects that undermine simple directional antenna approaches.
Solution Approach 2:
The patent implements feedback mechanisms where the system continuously monitors the self-interference signal characteristics and adjusts cancellation parameters accordingly. This feedback loop enables the system to adapt to changing channel conditions including multipath components, maintaining reliability while achieving good passive cancellation results.
3Measurement precision
If signal-injection self-interference cancellation is implemented with antenna placement calibration, then self-interference suppression at center frequency is improved, but frequency drift performance deteriorates
Solution Approach 1:
The patent transforms the static antenna placement calibration into a dynamic system that continuously adapts to frequency changes. By implementing adaptive signal processing and real-time parameter adjustment across RF and digital domains, the system maintains effective self-interference suppression even when frequency drift occurs, converting a frequency-specific solution into a broadly adaptive one.
Solution Approach 2:
The patent performs preliminary calibration and characterization of the self-interference channel across a range of frequencies, storing this information for use during operation. This preliminary action enables the system to quickly adapt to frequency drift without requiring complex real-time recalibration, maintaining both center frequency suppression and frequency drift performance.
4Productivity
If in-band full-duplex operation is implemented, then spectrum resource efficiency is improved, but self-interference cancellation requirements increase
Solution Approach 1:
The patent segments the complex self-interference cancellation task across multiple domains (RF, hybrid, digital) and multiple processing stages. This segmentation distributes the computational and hardware complexity, making in-band full-duplex operation feasible by preventing any single component from becoming prohibitively complex while still achieving the required cancellation levels for efficient spectrum reuse.
Data Source
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AI summary
A transceiver (1000) comprises an antenna arrangement (100) configured for interfacing a wireless transmission channel and comprising an interface (110) for receiving a sending signal (202) and an interface for providing a receiving signal (106). The transceiver comprises a main transmitter (200), an analog domain filter (300; 300'; 300"; 300"'), an auxiliary transmitter (400), a radio frequency interference removal stage (500), a main receiver (600), a feedback receiver (700) and a processor (800; 800') configured performing digital signal operations. The transceiver (1000) is configured for performing interference cancellation on a receiving signal in a radio frequency domain and in a digital domain.