Co-located Optical Link Fault Localization via MDSC Correlation

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Solution Overview

Problem

Existing methods for locating faults in optical communication links, such as Optical Time Domain Reflectometry (OTDR), are limited in accuracy and coverage, especially when faults occur in portions of links that are not equipped with OTDR devices or when links are partially co-located, making it difficult to determine the exact location of faults across multiple network domains.

Innovation Solution

A method and apparatus that utilize a Multi-Domain Service Coordinator (MDSC) to share information between network domains, determining co-location of faulted link portions and identifying the fault location by correlating notifications from different network domains, even if only one domain has OTDR devices, thereby enhancing fault localization accuracy and reducing repair times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If OTDR devices are installed on all optical links to improve fault location accuracy, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvefault location accuracyVSAvoidnumber of OTDR devices

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a Multi-Domain Service Coordinator (MDSC) as an intermediary system that collects, correlates, and processes fault location information from multiple network domains. The MDSC receives OTDR traces and fault notifications from different domains, performs cross-domain correlation analysis, and determines the actual fault location by identifying co-located link portions, eliminating the need to deploy OTDR devices on every single optical link

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent merges fault location capabilities across multiple network domains by combining information from different OTDR devices located in different domains. By correlating fault notifications and OTDR traces from multiple sources and identifying co-located link portions, the system achieves comprehensive fault location coverage without requiring every link to have its own OTDR device

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If OTDR devices are deployed on every optical link to ensure fault detection coverage, then reliability is improved, but loss of information is reduced through better localization

Engineering Contradiction:

Improvefault detection coverageVSAvoidfault location information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism where the MDSC collects fault notifications and OTDR traces from multiple domains, correlates this information, and uses the correlation results to improve future fault location accuracy. The system learns from each fault event and refines its ability to locate faults in co-located link portions by analyzing patterns across multiple domains

Inventive Principle:

Principle #23Feedback

3Device complexity

If manual fault location methods are used to reduce device complexity, then device complexity is reduced, but loss of time increases due to slower fault identification

Engineering Contradiction:

Improvefault location system complexityVSAvoidfault repair time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by pre-establishing the correlation relationships between optical links in different domains and maintaining updated information about co-located link portions. When a fault occurs, the MDSC can immediately query pre-collected OTDR traces and correlation data, eliminating the need for time-consuming manual investigation and enabling rapid fault location

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for more precise fault location across co-located optical link portions, even without OTDR devices on all links, improving fault detection and repair efficiency by leveraging shared information across multiple domains.

Implementation Method 1

The pulses may undergo attenuation, scattering and Fresnel reflections in the fiber due to fiber properties or fiber damage

Methodology Applied

Scientific EffectAttenuation: Absorption (EM radiation)

Implementation Method 2

The pulses may undergo attenuation, scattering and Fresnel reflections in the fiber due to fiber properties or fiber damage

Methodology Applied

Scientific EffectScattering: Scattering

Implementation Method 3

The pulses may undergo attenuation, scattering and Fresnel reflections in the fiber due to fiber properties or fiber damage

Methodology Applied

Scientific EffectFresnel reflections: Fresnel Diffraction

Implementation Method 4

By measuring the round trip time, localization of the fiber damage may be possible

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3692655B1Locating a fault in an optical communication link

Publication Date: 2023.09.27 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

Methods and apparatus are provided for locating a fault in an optical communication link. In one aspect, a method comprises determining a fault in a first optical link, and determining a fault in a second optical link. The method then determines that a first portion of the first optical link is co-located with a second portion of the second optical link and identifies, as a result of determining that the first portion is co-located with the second portion, that the fault in the first optical link is located in the first portion and/or the fault in the second optical link is located in the second portion.