Application of statistical inference to optical time domain reflectometer data
AssigneeAT&T Corp.
InventorsMichael Asher, Hossein Eslambolchi, Chuck Giddens, John Sinclair Huffman, Harold Stewart
Life of this patent
Estimating the term…
Abstract
The present invention relates to a method for interpreting data obtained by measuring a length of optical fiber using an optical time domain reflectometer (OTDR), and comparing that measurement to a reference measurement. The technique uses statistical inference to determine a whether a reference trace is valid by comparing that trace to a more recent test trace. One technique uses a chi-squared best fit of an array reflectance spike occurrences along the fiber to a historical reference array.
Claims19
A method for validating a reference trace of reflective characteristics in an optical fiber, the reference trace being stored in a memory accessible by a statistical post-processor, the method comprising the steps of:
- receiving parameters from a test OTDR trace Ttest of the optical fiber, the parameters including at least one array parameter P[ ]test;
- retrieving from a memory parameters from a reference OTDR trace Tref, the parameters including at least one array parameter P[ ]ref;
- correlating fiber characteristics represented by P[ ]ref with fiber characteristics represented by P[ ]test using a predetermined significance level;
- based on the correlating step, determining whether Tref is valid, and
- if Tref is invalid, then replacing Tref in the memory.
A machine readable medium containing configuration instructions for performing a method for validating a reference trace of reflective characteristics in an optical fiber, the method comprising the steps of:
- receiving parameters from a test OTDR trace Ttest of the optical fiber, the parameters including at least one array parameter P[ ]test;
- retrieving from a memory parameters from a reference OTDR trace Tref, the parameters including at least one array parameter P[ ]ref;
- correlating fiber characteristics represented by P[ ]ref with fiber characteristics represented by P[ ]test using a predetermined significance level;
- based on the correlating step, determining whether Tref is valid if Tref is not valid, then replacing in the memory Tref with Ttest.
Dependencies are inferred from the claim text.