Network Unit Fiber Line Fault Localization OxDR

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Solution Overview

Problem

Existing monitoring solutions for fiber lines in Fiber to the Radio head (FTTRh) communications networks are inefficient and inaccurate, failing to effectively detect and localize faults in these networks.

Innovation Solution

A network unit equipped with a detecting circuit to identify faults based on monitored power and an Optical x Domain Reflectometry (OxDR) circuit to initiate measurements, analyzing traces to localize faults or confirm their absence, utilizing standard Optical Line Supervision (OLS) and Received/Transmitted Signal Strength Indicator (RSSI/TSSI) parameters, along with Subcarrier Multiplexing (SCM) and Wavelength Division Multiplexing (WDM) techniques for efficient monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If standard Optical Line Supervision (OLS) and RSSI/TSSI parameters are used for monitoring, then the monitoring system is simple to implement, but the fault detection accuracy and localization precision are insufficient

Engineering Contradiction:
Improvefault detection accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the fiber line monitoring into multiple functional modules: OLS power monitoring module, OxDR measurement initiation module, trace analysis module, and fault localization module. Each module performs a specific function, allowing the system to achieve high measurement precision through specialized processing while managing complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary power monitoring using OLS to detect indications of faults before initiating more complex OxDR measurements. This preliminary action allows the system to filter out normal variations and only trigger detailed measurements when actual faults are suspected, improving detection accuracy while reducing overall system complexity by avoiding continuous complex measurements.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If continuous OxDR measurements are performed over the fiber line, then fault localization precision is improved, but the energy consumption and measurement time increase

Engineering Contradiction:
Improvefault localization precisionVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic OxDR measurements triggered by fault indications detected through power monitoring, rather than continuous measurements. The system monitors power levels continuously but only initiates energy-intensive OxDR measurements when anomalies are detected, achieving high fault localization precision only when needed and significantly reducing average energy consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The network unit performs self-diagnosis by monitoring its own power levels and automatically initiating OxDR measurements when faults are detected. This self-service approach eliminates the need for external monitoring equipment, reducing overall system energy consumption while maintaining high measurement precision when faults occur.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If power monitoring is used to detect faults, then the monitoring method is simple, but the ability to localize faults accurately is limited

Engineering Contradiction:
Improvemonitoring method simplicityVSAvoidfault location information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent uses OxDR measurements as an intermediary tool that bridges the gap between simple power monitoring and detailed fault localization. Power monitoring serves as the simple detection mechanism, while OxDR acts as the intermediary that provides precise location information, combining the advantages of both simplicity and accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions from one-dimensional power level monitoring to two-dimensional analysis by adding spatial dimension through OxDR trace analysis. This allows the system to maintain simple power monitoring operations while gaining fault location information through the additional spatial dimension provided by reflectometry traces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Enables efficient and accurate detection and localization of faults in FTTRh networks with ring or tree topologies, enhancing fault management and reducing service disruptions.

Implementation Method 1

initiates an Optical x Domain Reflectometry, OxDR, measurement over the fiber line

Methodology Applied
Scientific EffectOptical backscattering: Scattering

Implementation Method 2

detects an indication of a fault along the fiber line based on monitoring power

Methodology Applied
Scientific EffectOptical power detection: Photoelectric Effect

Data Source

PatentEP3005585B1Network unit and method for monitoring a fiber line
Publication Date: 2020.08.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3005585B1 patent drawingFigure 1
  • EP3005585B1 patent drawingFigure 2
  • EP3005585B1 patent drawingFigure 3

AI summary

Embodiments herein relate to a method in a network unit (14) for monitoring a fiber line between a radio base station (10) and a radio head (12) in a Fiber to the Radio Head communications network. The Fiber to the Radio Head communications network comprises a ring architecture or a tree architecture of fiber, with Subcarrier Multiplexing, SCM, downstream transmissions and Wavelength Division Multiplexing, WDM, upstream transmissions. The monitoring comprises that the network unit(14) detects an indication of a fault along the fiber line based on monitoring power. The network unit(14) initiates, in response to detect the indication, an Optical x Domain Reflectometry, OxDR, measurement over the fiber line. Additionally, the network unit analyses a trace from the OxDR measurement for localizing the fault or for deciding that the indicated fault is not a fault along the fiber line.