Self-Interference Cancellation Using Phase Detector and Adaptive Filter
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Solution Overview
Problem
Wireless communication systems face challenges in efficiently removing self-interference signals, particularly those with random phase components, which can significantly impact reception sensitivity due to their increased influence compared to external interference signals in weak electric fields.
Innovation Solution
An electronic device equipped with a phase detector and an adaptive filter that estimates the phase of transmission signals and uses this information to efficiently remove self-interference signals by updating filter coefficients based on statistical characteristics, thereby reducing the impact of self-interference on reception sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional adaptive filtering is used to remove self-interference signals, then the device can operate with standard components, but the time required to remove self-interference signals is excessive and reception sensitivity is degraded
Solution Approach 1:
The phase detector detects the phase of the transmission signal before the adaptive filter processes the reception signal. By obtaining phase information in advance and using it to initialize or guide the adaptive filtering process, the system reduces the convergence time required to remove self-interference signals, thereby quickly improving reception sensitivity without requiring complex additional hardware
Solution Approach 2:
The system uses the detected phase information as feedback to continuously adjust and optimize the adaptive filter's performance. The phase detector provides real-time phase measurements that feed back into the filtering process, enabling the system to adapt to changing signal conditions and maintain optimal self-interference cancellation performance over time
2Productivity
If the adaptive filter processes signals without phase information, then the processing is simpler, but the self-interference signal removal is inefficient
Solution Approach 1:
The phase detector serves as an intermediary component that bridges the transmission signal and the adaptive filter. It extracts critical phase information from the transmission signal and provides it to the adaptive filter, enabling more efficient self-interference removal. This intermediary approach adds minimal complexity while significantly improving processing efficiency
Solution Approach 2:
The system changes the parameter being utilized from the full complex signal to specifically the phase component of the transmission signal. By focusing on extracting and utilizing only the phase parameter, the system achieves efficient self-interference cancellation with reduced computational complexity compared to processing entire signal waveforms
Data Source
Figure 1A~1B
Figure 2
Figure 3A
AI summary
A wireless communication device includes a transmission radio frequency (RF) chain configured to transmit a radio signal, and processing circuitry configured to cause the wireless communication device to detect that the transmission RF chain has transitioned from an inactive state to a first active state, determine whether to detect an updated value of a phase of a self-interference signal in response to detecting that the transmission RF chain has transitioned from the inactive state to the first active state, and modify a weight vector of an adaptive filter corresponding to the self-interference signal based on the updated value of the phase or a previous value of the phase.