Polarization Multiplexing Phase Estimation via Adaptive Pilot Extraction
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Solution Overview
Problem
In polarization multiplexing systems, the pilot-based carrier phase noise compensation method fails to accurately estimate phase due to counteraction of pilots in orthogonal polarization signals, leading to degraded system performance.
Innovation Solution
The method involves performing state of polarization rotation on received signals according to a previous rotation angle and using adaptive filtering to extract pilots, updating coefficients based on error calculations, and performing clock phase adjustment to ensure synchronization, thereby enhancing pilot power and accuracy of carrier phase estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pilot-based carrier phase noise compensation method is applied to polarization multiplexing system, then carrier phase noise compensation can be performed, but pilots in two state of polarization signals counteract each other at specific polarization angles and DGD values, causing pilot disappearance and noise extraction
Solution Approach 1:
The patent segments the polarization multiplexing signal into two separate orthogonal state of polarization signals (Xin and Yin). By processing each polarization component independently through separate adaptive filters with coefficients hx and hy, the system avoids the counteraction problem that occurs when pilots from different polarizations interfere with each other. This segmentation allows reliable phase estimation without pilot cancellation.
Solution Approach 2:
The patent introduces adaptive filtering coefficients (hx, hy) as intermediaries between the received polarization signals and the pilot extraction process. These coefficients act as mediators that optimally combine the orthogonal polarization components to recover the pilot signal, preventing direct counteraction while enabling accurate phase noise compensation.
2Measurement precision
If adaptive filtering is used to extract pilot from orthogonal polarization signals, then pilot power is strengthened and noise extraction is prevented, but device complexity increases due to additional filtering operations
Solution Approach 1:
The adaptive filter structure serves multiple functions simultaneously: it performs pilot extraction, compensates for polarization mode dispersion, and optimizes the combination of orthogonal polarization components. This multi-functionality reduces the need for separate processing stages, thereby limiting the increase in device complexity while achieving high pilot extraction accuracy.
Solution Approach 2:
The adaptive filtering coefficients are updated automatically based on the received signal characteristics through error calculation and coefficient optimization. This self-adjusting mechanism eliminates the need for manual calibration or external intervention, allowing the system to adapt to changing channel conditions while maintaining manageable complexity through automated operation.
Data Source
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AI summary
A phase estimation method and apparatus for a polarization multiplexing system are provided. The method includes: performing, by a receive end, state of polarization rotation on a received first state of polarization signal and second state of polarization signal according to an angle of previous state of polarization rotation, and extracting a pilot by means of adaptive filtering; and performing carrier phase estimation according to the extracted pilot. This prevents a noise signal from being extracted and can make a carrier phase estimation result more accurate.