Wavelength Selection for DWDM Networks Reducing 3R Regenerator Count

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Solution Overview

Problem

In dense wavelength division multiplexing (DWDM) networks, the existing methods for assigning wavelengths to light paths are inefficient, leading to excessive use of 3R regenerators, which are costly and necessary for maintaining signal quality over long distances, especially in long-haul networks where physical impairments vary across the C band.

Innovation Solution

A method that assesses the suitability of wavelengths for light paths by using an optical performance database to determine extended feasible light paths and calculates a score indicating their suitability for future use, allowing for proactive selection of wavelengths that minimize the need for 3R regenerators by reserving better performing frequencies for future use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If existing wavelength assignment methods are used, then wavelength allocation is simple, but the number of 3R regenerators required increases excessively

Engineering Contradiction:

Improvenumber of 3R regeneratorsVSAvoidwavelength assignment complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent performs preliminary assessment of wavelength suitability by calculating extended feasible light paths and suitability scores before actual wavelength assignment. This proactive evaluation identifies wavelengths that will minimize future 3R regenerator needs, rather than simply assigning the first available wavelength. The optical performance database is pre-populated with feasibility information, enabling informed wavelength selection that reduces 3R regenerator requirements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the suitability score, calculated based on extended feasible light paths and optical performance data, feeds back into the wavelength assignment decision. This feedback loop allows the system to learn from network characteristics and optimize wavelength assignments to reduce 3R regenerator usage, transforming the complex assessment information into actionable assignment guidance.

Inventive Principle:

Principle #23Feedback

2Reliability

If wavelengths are assigned without assessing extended feasible light paths, then assignment process is faster, but signal quality degradation occurs requiring more 3R regenerators

Engineering Contradiction:

Improvesignal qualityVSAvoidwavelength assignment time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies partial action by assessing only the most critical feasibility criteria through the suitability score calculation, rather than exhaustively evaluating every possible parameter. The system calculates extended feasible light paths and suitability scores to a sufficient degree to ensure signal quality, without performing unnecessary additional assessments that would significantly increase assignment time. This balanced approach maintains reliability while controlling processing time.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If better performing frequencies are used immediately, then current light path performance is optimized, but future light paths may require more 3R regenerators

Engineering Contradiction:

Improvecurrent light path performanceVSAvoidfuture network flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of assigning the best-performing wavelengths to current light paths, the patent inverts the approach by assigning wavelengths with lower suitability scores for extended feasible light paths. This inversion strategy intentionally reserves better-performing frequencies for future light paths, balancing current performance needs with future network flexibility and reducing the likelihood of future 3R regenerator requirements.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10880034B2Method, computer program and routing engine for proactive performance-based frequency management

Publication Date: 2020.12.29 XIEON NETWORKS SARL

AI summary

Disclosed herein is a method of assigning a wavelength to a given light path in a wavelength switched optical network, as well as a corresponding routing engine and computer program. The method comprises the following step. For each of a plurality of possible wavelengths for said light path, retrieving information from an optical performance database (30) allowing to assess whether the given wavelength meets a predetermined feasibility criterion with regard to said given light path; if the given wavelength is found to meet the predetermined feasibility criterion, determining a set of extended feasible light paths, each of which fully including the given light path, but containing one or more additional nodes; and calculating a first score based on said determined set of extended feasible light paths, wherein said method further comprises a step of choosing, based on said first score, a wavelength that has a first score indicating a low suitability for providing useful extended feasible light paths for future use.