Microwave Signal Processing Phase Noise Suppression
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Solution Overview
Problem
Microwave communication systems face challenges in effectively suppressing phase noise due to the narrow bandwidth of phase-locked loops, which limits their phase noise suppression capability.
Innovation Solution
A method and device for signal processing in microwave communication systems that perform phase noise estimation, channel estimation, and phase rotation to improve phase noise suppression, using a phase noise estimator, multi-path channel estimator, equalizer, phase estimator, and phase-locked loop to filter out phase noise even with a narrow phase-locked loop bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bandwidth of the phase-locked loop is set to be large to improve phase noise suppression capability, then the phase noise suppression capability is improved, but the phase-locked loop becomes divergent
Solution Approach 1:
The patent segments the phase noise suppression process into two distinct stages: a wide bandwidth phase noise estimator that captures most phase noise components, and a narrow bandwidth phase-locked loop that handles residual phase noise. This segmentation allows each component to operate within its stable bandwidth range while collectively achieving effective phase noise suppression without divergence.
Solution Approach 2:
The patent applies preliminary action by using the wide bandwidth phase noise estimator to pre-remove the majority of phase noise components before the signal enters the narrow bandwidth phase-locked loop. This preliminary removal reduces the burden on the phase-locked loop, allowing it to operate stably with narrow bandwidth while still achieving effective overall phase noise suppression.
2Stability of the object's composition
If the bandwidth of the phase-locked loop is set to be narrow to maintain stability, then the phase-locked loop stability is maintained, but the phase noise suppression capability is limited
Solution Approach 1:
The patent divides the phase noise suppression function between a wide bandwidth estimator component and a narrow bandwidth phase-locked loop component. The wide bandwidth component handles the bulk of phase noise suppression while the narrow bandwidth component maintains stability and handles residual noise, achieving both goals simultaneously through functional segmentation.
Solution Approach 2:
The patent introduces an intermediary component - the wide bandwidth phase noise estimator - that acts as a mediator between the received signal and the narrow bandwidth phase-locked loop. This intermediary pre-processes the signal by removing major phase noise components, enabling the narrow bandwidth phase-locked loop to maintain stability while contributing to overall phase noise suppression.
3Reliability
If the bandwidth of the phase-locked loop is increased to improve phase noise suppression, then the phase noise suppression capability is improved, but the equalizer convergence speed decreases
Solution Approach 1:
The patent segments the signal processing chain so that the wide bandwidth phase noise estimator operates independently and does not affect the equalizer convergence process. By separating phase noise estimation from equalization, the system achieves effective phase noise suppression while maintaining fast equalizer convergence speed, as the equalizer can operate with standard convergence criteria without being constrained by phase noise suppression requirements.
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AI summary
A method and a device which are for signal processing and are applied to a microwave communication system are disclosed. The method includes: performing equalization processing on each input signal by using an equalizer so as to obtain an equalized signal corresponding to the each input signal; performing phase estimation on phase noise in the equalized signal to obtain an estimated phase of the phase noise; performing phase rotation on the equalized signal to offset the estimated phase of the phase noise, so as to obtain a phase rotation signal; suppressing residual phase noise in the phase rotation signal by using a phase-locked loop so as to output an error signal and a received signal; and performing an iterative update on a filter coefficient of the equalizer by using the error signal.