TECHNOLOGY FOR FAULT ALLOCATION IN PASSIVE OPTICAL NETWORKS (PON)

• US 20120002959A1
• Filed: 06/22/2011
• Published: 01/05/2012
• Est. Priority Date: 06/30/2010
• Status: Active Grant

• Current Assignee: ECI Telecom Limited (Shaul Shani)
• Original Assignee: ECI Telecom Limited (Shaul Shani)
• Inventors: MELAMED, Amitay
• Granted Patent: US 8,805,184 B2
• Time in Patent Office: Days
• US Class Current: 398/10
• CPC Class Codes: H04B 10/0771 Fault location on the transmission path
• CPC Class Codes: H04B 10/272 Star-type networks or tree-type networks
• CPC Class Codes: H04J 14/0272 Transmission of OAMP information
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04Q 11/0067 Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring

Abstract

A method for allocating faults in a passive optical network (PON) by placing a number of passive unique optical correlators in a number of respective diagnostic points of the PON, each of the passive unique optical correlators being responsive to an optical diagnostic signal by returning a predetermined unique matching signal; by further transmitting the diagnostic optical signal in the PON towards the diagnostic points to receive upstream response signals from the correlators. Upon detecting presence or absence, in the received response signals, of a predetermined unique matching signal expected from a specific optical correlator, judging about a fault in proximity of the respective specific diagnostic point.

Claims

1. A method for allocating faults in a passive optical network (PON), comprising

placing a number of passive unique optical correlators in a number of respective diagnostic points of the PON, each of the passive unique optical correlators being responsive to an optical diagnostic signal by returning a predetermined unique matching signal;

transmitting the diagnostic optical signal in said PON, towards said diagnostic points,

receiving upstream response signals from said number of passive optical correlators placed at said diagnostic points of the PON,

detecting presence or absence, in said received response signals, of a predetermined unique matching signal expected from a specific optical correlator out of said correlators,

judging about a fault in proximity of a specific diagnostic point, based on the presence or absence and/or a level of said specific matching signal expected from the unique passive optical correlator placed in said specific diagnostic point.

2. The method according to claim 1, further comprising

generating said diagnostic optical signal by selectively applying to a carrier optical signal one unique signature at a time, said unique signature being selected from a plurality of signatures unique for the PON and respectively associated with the number of passive unique optical correlators;

detecting said predetermined unique matching signal, if returned by one of said unique passive optical correlators responsive to the unique signature carried by the diagnostic signal.

3. The method according to claim 1, further comprising judging, according to parameters of the matching signal, about distance up to said diagnostic point and/or condition of a communication line and/or equipment up to said diagnostic point.

4. The method according to claim 1, wherein said PON comprises an Optical Line Termination (OLT) connected via optical fibers to a plurality of Optical Network Terminations (ONTs),

the method further comprises

arranging said diagnostic points at least in proximity to one or more of the ONTs;

storing information on the plurality of unique signatures in a data base;

transmitting the diagnostic optical signal, in the direction from the OLT downstream, towards said ONTs;

receiving the upstream response signals from the ONTs;

associating the presence or absence of the predetermined matching signal, if detected, with the stored information on the plurality of unique signatures;

in case of absence of the predetermined matching signal, allocating a fault in a PON section preceding the optical correlator responsive to said specific unique signature.

5. The method according to claim 4, wherein said information on the plurality of unique signatures comprises said signatures, the respective matching signals, the respective passive correlators and their respective locations in the PON.

10. A software product stored on a computer readable non-transitory medium, comprising computer implementable instructions and/or data which, when executed by a computer processor, carry out the method according to claim 1.

6. A diagnostic tool for a PON network, the tool comprising a passive optical correlator to be connected to an optical fiber, and being responsive to an optical diagnostic signal if applied to the passive optical correlator, by returning a predetermined unique matching signal.

7. The diagnostic tool according to claim 6, being responsive to the optical diagnostic signal carrying a specific unique signature.

8. The diagnostic tool according to claim 7, wherein the unique signature comprises a specific binary code applied to a carrier optical signal, and wherein the correlator comprises a number of delay elements arranged in parallel in such a manner that, all “

1”

-level pulses of said specific binary code, upon passing via the parallel delay elements, coincide in time and get summarized so that the sum thereof forms the predetermined matching signal;

the correllator being adapted to return said predetermined matching signal in response to the diagnostic signal for further processing.

9. A system for fault allocation in a PON network, comprising an OLT connected by optical fibers to a number of ONTs, a number of diagnostic tools according to claim 6, positioned at various diagnostic points of the PON network;

wherein

the system is provided with a generator for generating a diagnostic downstream signal,

the OLT is associated with a processing unit PU accommodating a data base for storing information on a plurality of unique matching signals, the diagnostic tools associated with said matching signals and location of said diagnostic tools,

the processing unit being adapted to;

detect said unique matching signals received from said ONTs,

to associate the matching signals with the information stored in the data base,

to judge about possible faults in the PON based on detecting specific unique matching signals and parameters of said signals.