Full-Duplex Radio Self-Interference Cancellation Calibration
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Solution Overview
Problem
In radio full duplex communications, achieving high rejection of self-interference is challenging due to the high power transmitted signals causing distortion in received signals, requiring accurate calibration and compensation mechanisms to minimize distortions introduced by measurement and cancellation systems.
Innovation Solution
A method and system for calibrating a full-duplex radio system by transmitting and receiving signals through an antenna, using a secondary transmitter to cancel reflections and an equalizer to compensate for distortions, allowing simultaneous transmission and reception with improved self-interference rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power transmitted signals are used, then transmission power is improved, but self-interference increases causing distortion in received signals
Solution Approach 1:
The patent measures the self-interference signal and uses it to generate a cancellation signal. The harmful self-interference is converted into a useful cancellation reference that, when subtracted from the received signal, removes the interference and improves received signal quality.
Solution Approach 2:
The patent introduces a cancellation signal as an intermediary element. This cancellation signal is generated based on the measured self-interference and is used to neutralize the harmful effects of self-interference in the received signal path.
2Object-generated harmful factors
If signal cancellation is implemented, then self-interference rejection is improved, but measurement and cancellation system distortions are introduced
Solution Approach 1:
The patent implements a feedback mechanism where the received signal is measured and used to generate the cancellation signal. This closed-loop approach allows the system to adapt to actual self-interference conditions and compensate for distortions introduced by the cancellation process itself.
Solution Approach 2:
The patent replaces complex hardware-based cancellation mechanisms with signal processing-based cancellation. By using digital signal processing to generate and apply cancellation signals, the system achieves high self-interference rejection while minimizing mechanical and hardware-induced distortions.
3Manufacturing precision
If calibration is performed to compensate distortions, then signal quality is improved, but system complexity increases
Solution Approach 1:
The patent implements self-calibration where the system uses its own transmitted signal and received signal to automatically determine and compensate for distortions. The calibration process is performed autonomously without requiring external test equipment or manual adjustment, reducing overall system complexity.
Solution Approach 2:
The patent combines the calibration function with the normal signal reception and cancellation operations. The same signal paths and processing elements used for self-interference cancellation are also used for distortion measurement and compensation, eliminating the need for separate calibration hardware and reducing system complexity.
Data Source
AI summary
In one embodiment, a method for calibrating a full-duplex radio system includes transmitting, by a first radio transmitter, a first signal and receiving, by a first radio receiver, a first version of the first signal. The method also includes receiving, by a second radio receiver, a second version of the first signal and transmitting, by a second radio transmitter, a second signal. Additionally, the method includes receiving, by the first radio receiver, a received version of the second signal and determining a response from the second radio transmitter to the first radio receiver in accordance with the first version of the first signal, the second version of the first signal, and the received version of the second signal.