Patent ID: 8724102
Filing Date: 2014-05-13
Classification: G01M,H04B

Abstract:
1. A method of performing fault analysis in a Passive Optical Network, PON, by using Optical Time Domain Reflectometry, OTDR, comprising: triggering a new OTDR measurement, wherein a previous reference measurement has been made indicating an original state of said PON; inserting an OTDR measurement signal into a multistage splitter before a last splitter stage of said multistage splitter, and wherein the last splitter stage is of ratio 2:N; obtaining at least one new event location based on the OTDR measurement signal; and calculating a fault magnitude at a given location by subtracting an event magnitude obtained from the new OTDR measurement from said reference OTDR measurement and taking into account a number of drop links connected to the last splitter stage in the reference measurement and the new measurement, thereby enabling determination of position and severity of fault locations, wherein a total loss, TLref, in said reference OTDR measurement is represented by where N is the number of branches of the last splitter stage of said multistage splitter, J is the number of events and M is the number of non-connected branches of said last splitter stage of said multistage splitter.