Optical Receiver Phase Estimation Using Test Phases and Interpolation
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Solution Overview
Problem
Current WDM systems face challenges in accurately and efficiently correcting phase errors in received signals due to random phase fluctuations, especially when using multiple digital sub-carriers, which increases computational complexity and ambiguity in carrier recovery.
Innovation Solution
The implementation of a digital signal processor in optical receivers that applies test phases to input signals, calculates error values, and determines phase estimates by comparing updated metric values, allowing for accurate phase correction and carrier recovery even with multiple sub-carriers, reducing computational complexity and ambiguity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple digital sub-carriers are used in WDM systems, then data transmission capacity is improved, but computational complexity in carrier recovery increases
Solution Approach 1:
The patent segments the carrier recovery process into distinct stages: test phase application to individual sub-carriers, error value calculation for each sub-carrier, selective combination of error values, and metric value comparison. This segmentation allows the system to handle multiple sub-carriers systematically, improving data transmission capacity while managing computational complexity through structured processing.
Solution Approach 2:
The patent applies partial action by selectively combining error values from only certain sub-carriers rather than processing all sub-carriers equally. The digital signal processor identifies and combines error values from sub-carriers that provide the most useful information for phase correction, reducing unnecessary computational operations while maintaining recovery accuracy.
2Productivity
If multiple digital sub-carriers are used in WDM systems, then data transmission capacity is improved, but ambiguity in carrier recovery increases
Solution Approach 1:
The patent implements feedback through the calculation and comparison of metric values for different test phases. The digital signal processor calculates metric values based on combined error values, compares these metrics across different test phases, and uses the comparison results to determine the optimal phase estimate. This feedback mechanism resolves ambiguity by systematically evaluating multiple phase possibilities and selecting the most accurate one.
Solution Approach 2:
The patent changes parameters by applying different test phases to the input signals and observing how error values and metric values change with each test phase. By systematically varying the test phase parameter and measuring the resulting error metrics, the system can identify the optimal phase that minimizes error, thereby resolving carrier recovery ambiguity while maintaining high data transmission capacity.
3Measurement precision
If test phases are applied to each input signal with error value calculation, then phase estimation accuracy is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating error values for each sub-carrier before combining them. The digital signal processor calculates error values for individual sub-carriers using test phases, then selectively combines these pre-calculated error values. This preliminary processing organizes the data in advance, enabling more efficient final phase estimation and reducing overall processing time while maintaining high phase estimation accuracy.
Data Source
AI summary
An optical receiver may receive input signals carried by sub-carriers, and may apply test phases to each input signal. The optical receiver may determine error values, associated with test phases, for each input signal. The optical receiver may calculate updated metric values, associated with the test phases, for a particular input signal, based on a first error value and a second error value. The first error value may be associated with a first sub-carrier, and the second error value may be associated with a second sub-carrier. The optical receiver may compare the updated metric values associated with the particular input signal, and may determine a test phase that represents an estimated phase, associated with the particular input signal, based on the comparison. The optical receiver may determine a phase estimate value based on the test phase, and may provide the phase estimate value to modify the particular input signal.