Equalizer Sampling Phase Optimization for Optical Links
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Solution Overview
Problem
Conventional communication receivers face suboptimal performance due to suboptimal sampling phase in equalizers, especially in optical links without dispersion compensation fibers, where chromatic dispersion and polarization mode dispersion need to be effectively managed for high baud rate data transmission.
Innovation Solution
An improved equalizer and method that optimizes the sampling phase using a target sampling phase estimator and sampling phase adjuster, which determine and adjust the sampling phase based on adaptable branch metrics and error events to maximize signal quality, incorporating a communication channel model and maximum likelihood sequence estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional equalizer with fixed sampling phase is used, then device complexity is reduced, but bit error rate performance deteriorates due to suboptimal sampling phase
Solution Approach 1:
The patent implements a dynamic sampling phase adjustment mechanism where the equalizer continuously adapts the sampling phase based on received signal characteristics. The sampling phase is no longer fixed but dynamically optimized to maximize signal quality, directly resolving the contradiction between maintaining simple device structure and achieving reliable performance.
Solution Approach 2:
The equalizer performs self-adjustment of the sampling phase by analyzing its own received signal and automatically optimizing the sampling timing without requiring external intervention or complex additional hardware, thereby improving reliability while maintaining relatively simple device complexity.
2Reliability
If dispersion compensation fibers (DCF) are used, then chromatic dispersion is compensated, but noise and nonlinear effects increase
Solution Approach 1:
The patent replaces the physical dispersion compensation fiber (mechanical/optical system) with a digital signal processing approach in the equalizer. Instead of using DCF to physically compensate for chromatic dispersion, the equalizer uses adaptive filtering and sampling phase optimization to digitally correct dispersion effects, thereby eliminating the noise and nonlinear effects associated with DCF while maintaining signal quality.
3Reliability
If coherent transceivers are used, then chromatic dispersion is effectively compensated, but cost increases
Solution Approach 1:
The patent employs a cost-effective equalizer design that achieves dispersion compensation through digital signal processing rather than expensive coherent transceiver hardware. The solution uses simpler, cheaper components while maintaining effective dispersion compensation performance, making high baud rate data transmission economically viable.
4Reliability
If sampling phase is not optimized, then equalizer operation is simplified, but performance in dispersion-uncompensated links deteriorates
Solution Approach 1:
The equalizer automatically performs sampling phase optimization by analyzing the received signal characteristics and adjusting the sampling timing accordingly. This self-adjusting mechanism improves performance in dispersion-uncompensated links without requiring manual intervention or complex operational procedures, thereby maintaining ease of operation while enhancing reliability.
Data Source
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AI summary
The invention relates to an equalizer (100) for a communication receiver configured to receive a digital communication signal over a communication channel, the digital communication signal being sampled using a sampling signal defined by a sampling phase. The equalizer (100) comprises a communication channel modeler (101) configured to provide an adaptable communication channel model on the basis of the digital communication signal, wherein the adaptable communication channel model is defined by a plurality of adaptable branch metrics, a maximum likelihood sequence estimator (103) configured to estimate a sequence of symbols associated with the digital communication signal on the basis of the digital communication signal and the plurality of branch metrics, a target sampling phase estimator (105), wherein during a first target sampling phase estimation stage the target sampling phase estimator (105) is configured to determine for each sampling phase of a first plurality of sampling phases a first parameter on the basis of the plurality of adaptable branch metrics and to estimate a first target sampling phase on the basis of the plurality of first parameters, and a sampling phase adjuster (107) configured to adjust the sampling phase to the first target sampling phase.