OTDR Duplicate Measurement Detection via Backscattering Pattern
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Solution Overview
Problem
Communication network operators face challenges in detecting duplicate Optical Time-Domain Reflectometry (OTDR) measurements, which can be fraudulent or inadvertent, as existing methods cannot differentiate between measurements taken on the same optical fiber when saved in different data files.
Innovation Solution
A method that compares the backscattering patterns of OTDR traces to determine if they were acquired over the same optical fiber link, using correlation coefficients and identifying unique fiber spans with high ratios of backscattering pattern amplitude to electronic noise, and forms clusters of likely duplicate measurements to identify repeated testing on the same fiber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If OTDR measurements are saved in different data files, then data storage flexibility is improved, but duplicate detection capability deteriorates
Solution Approach 1:
The patent uses optical copying of the backscattering pattern from the physical fiber to create a unique digital fingerprint. This optical copy (the backscattering pattern) is stored with the measurement data, enabling duplicate detection across different files. The principle transforms a physical property (optical backscattering) into a detectable digital signature that travels with the data regardless of storage location.
2Productivity
If OTDR measurements are repeated on the same fiber to save time, then productivity is improved, but measurement accuracy deteriorates due to undetected duplicates
Solution Approach 1:
The system implements feedback by comparing the backscattering pattern fingerprint of each new measurement against existing measurements. When a duplicate is detected through pattern matching, the system provides feedback to flag or reject the measurement, preventing inaccurate results from being accepted. This closed-loop verification maintains accuracy while allowing rapid retesting when genuine new measurements are performed.
3Measurement precision
If backscattering patterns are compared across all measurements, then duplicate detection accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent extracts only the essential backscattering pattern fingerprint from the complete OTDR measurement data for comparison purposes. Instead of analyzing entire datasets, the method isolates and compares the unique optical fingerprint portion, significantly reducing computational complexity while maintaining duplicate detection accuracy. This extraction approach focuses computational resources on the discriminative features that actually identify duplicates.
4Stability of the object's composition
If OTDR test pulse characteristics are stabilized, then backscattering pattern consistency is improved, but adaptability to environmental variations deteriorates
Solution Approach 1:
The patent acknowledges that OTDR test pulse parameters (wavelength, power, pulse width) may vary due to environmental factors like temperature. Instead of rigidly stabilizing these parameters, the method uses parameter changes as part of the solution by focusing comparison on the backscattering pattern fingerprint which remains unique to each fiber segment regardless of minor parameter variations. The correlation-based comparison is robust to these parameter changes, maintaining both consistency and environmental adaptability.
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
Effectively detects duplicate OTDR measurements, preventing fraudulent practices and ensuring accurate testing of optical fibers by identifying clusters of measurements taken on the same optical fiber, thereby enhancing the reliability of test reports and reducing the risk of undetected issues.
Implementation Method 1
When such fluctuations interact with the OTDR test pulses, it creates interferences and modulations that produce a backscattering pattern in the acquired OTDR trace.
Data Source
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AI summary
There is provided a method, system and computer program for detecting duplicate OTDR measurements performed on a same fiber. It is determined whether OTDR traces are likely to have been acquired over the same optical fiber link by comparing the backscattering pattern associated with a given fiber span along the OTDR traces, which corresponds to a continuous optical fiber section.