Nonlinear Weighting Coefficient Calculation via Rational Function Approximation

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Solution Overview

Problem

Current methods for estimating nonlinear distortion in long-haul optical fiber communication systems lack the capability to obtain high-precision weighting coefficients, which is essential for accurate nonlinear distortion estimation and compensation.

Innovation Solution

A calculating apparatus and method that uses a rational function to perform approximation processing on the link loss/gain function, enabling the calculation of nonlinear weighting coefficients with an analytic closed solution, thereby facilitating high-precision estimation and compensation of nonlinear distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If numerical value solutions (distributed Fourier algorithm) are used to solve the nonlinear Schrödinger equation, then the accuracy of nonlinear distortion estimation is improved, but the computational complexity increases significantly

Engineering Contradiction:

Improvenonlinear distortion estimation accuracyVSAvoidcomputational complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms the complex numerical solution problem into a simplified analytical solution by changing the parameter representation method. Specifically, it uses parameterized functions to model the nonlinear weighting coefficients, allowing closed-form mathematical expressions instead of iterative numerical computations. This parameter transformation maintains estimation accuracy while dramatically reducing computational complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates simplified analytical models that copy the essential characteristics of the complex numerical solutions. By developing analytical expressions for nonlinear weighting coefficients that mirror the behavior of numerical solutions, the system achieves comparable accuracy without requiring intensive computational resources.

Inventive Principle:

Principle #26Copying

2Device complexity

If analytical approximation methods are used to solve the nonlinear Schrödinger equation, then the computational complexity is reduced, but the precision of nonlinear distortion estimation deteriorates

Engineering Contradiction:

Improvecomputational complexityVSAvoidnonlinear distortion estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces refined parameter representations for nonlinear weighting coefficients using analytical functions with adjustable parameters. These parameterized analytical solutions can be tuned to match numerical solution accuracy while maintaining computational efficiency. The key is transforming the problem into a parameter optimization task rather than a full numerical simulation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical computational process of numerical iteration with an analytical mathematical substitution. Instead of repeatedly computing numerical solutions, the system uses closed-form analytical expressions that directly calculate nonlinear weighting coefficients, substituting iterative computation with direct mathematical evaluation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If high-precision nonlinear weighting coefficients are obtained through complex numerical methods, then the accuracy of transmission system performance evaluation is improved, but the ease of operation and implementation becomes difficult

Engineering Contradiction:

Improvetransmission system performance evaluation accuracyVSAvoidimplementation ease

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent creates simplified analytical models that replicate the essential behavior of complex numerical methods. By developing closed-form expressions for nonlinear weighting coefficients that copy the key characteristics of numerical solutions, the system achieves accurate performance evaluation without requiring complex computational implementations.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent substitutes complex numerical computation mechanisms with simpler analytical mathematical expressions. This replacement makes the system easier to implement and operate while maintaining high precision in transmission system performance evaluation through closed-form solutions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9998223B2Calculating apparatus and method for nonlinear weighting coefficient

Publication Date: 2018.06.12 FUJITSU LTD

AI summary

Embodiments of the present disclosure provide a calculating apparatus and method for nonlinear weighting coefficient. The calculating apparatus for nonlinear weighting coefficient includes: an approximation processing unit configured to use a rational function to perform approximation processing on a link loss/gain function in intra-channel nonlinear distortion estimation; and a coefficient calculating unit configured to calculate a nonlinear weighting coefficient in the nonlinear distortion estimation by using the approximated link loss/gain function and a large dispersion approximation, to obtain an analytical closed solution of the nonlinear weighting coefficient. With the embodiments of the present disclosure, a weighting coefficient of high precision may be obtained, thereby performing high-precision estimation on nonlinear distortion in case of loss.