OPTICAL LINE MONITORING SYSTEM AND METHOD

• US 20140308033A1
• Filed: 10/10/2012
• Published: 10/16/2014
• Est. Priority Date: 10/11/2011
• Status: Active Grant

• Current Assignee: LS Cable Limited (LS Corporation)
• Original Assignee: LS Cable Limited (LS Corporation)
• Inventors: Park, Ji-Sang, Park, Lae-Hyuk, Kim, Ki-Yeul, Yang, Eun-Jeong, Han, Kwan-Hee
• Granted Patent: US 9,407,360 B2
• Time in Patent Office: Days
• US Class Current: 398/25
• CPC Class Codes: H04B 10/07 Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
• CPC Class Codes: H04B 10/071 using a reflected signal, e.g. using optical time domain reflectometers [OTDR]

Abstract

Disclosed is an optical line monitoring system and method which detects an optical line where a disorder occurs, by using an OTDR (Optical Time Domain Reflectometer) pulse pattern with matching information. The optical line monitoring system generates and stores a reference OTDR pulse pattern matched with identification information of an optical channel service unit, and compares the matched reference OTDR pulse pattern with the OTDR pulse pattern collected at an inspection time to verify an optical line region where a disorder occurs.

Claims

1. An optical line monitoring method for monitoring a disorder of an optical line by using an optical line monitoring system, the method comprising:

(a) delivering status request optical signals to a plurality of optical channel service units and receiving a status response optical signal from each optical channel service unit;

(b) measuring a distance of each optical channel service unit based on a round-trip delay time of the received status response optical signal and storing the distance of each optical channel service unit as a reference status information table to be mapped with identification information of the corresponding optical channel service unit;

(c) delivering an OTDR (Optical Time Domain Reflectometer) pulse to each optical channel service unit which is in normal operation, receiving a plurality of individual OTDR pulses returned by reflection, and storing a reference OTDR pulse pattern exhibited by the plurality of individual OTDR pulses; and

(d) checking a distance of each individual pulse in the reference OTDR pulse pattern, and matching each individual pulse with the identification information of each optical channel service unit so that a proximity order of the individual pulses is identical to a proximity order of the optical channel service units in the reference status information table.

2. The optical line monitoring method according to claim 1, wherein the step (d) includes:

determining whether the number of individual pulses exhibited in the reference OTDR pulse pattern is identical to the number of optical channel service units recorded in the reference status information table;

in the case the number of individual pulses exhibited in the reference OTDR pulse pattern is not identical to the number of optical channel service units recorded in the reference status information table as a result of the determination, checking identification information of a plurality of optical channel service units whose difference in distance is not greater than a threshold value; and

matching the identification information of the plurality of checked optical channel service units to overlap at a single individual pulse.

3. The optical line monitoring method according to claim 2, after the step (d), further comprising:

(e) when an inspection time of the optical line comes, delivering OTDR pulses to the plurality of optical channel service units, receiving a plurality of OTDR pulses returned by reflection, and obtaining an OTDR pulse pattern exhibited by the plurality of OTDR pulses;

(f) comparing the individual pulses exhibited in the obtained OTDR pulse pattern with the individual pulses exhibited in the reference OTDR pulse pattern; and

(g) in the case a mismatched individual pulse is present as a result of the comparison, checking the identification information of an optical channel service unit matched with the mismatched individual pulse in the reference OTDR pulse pattern to identify an optical line region where a disorder occurs.

4. The optical line monitoring method according to claim 3,

wherein, in the step (b), an intensity of the status response optical signal received from each optical channel service unit is checked, and the intensity of each optical signal in the reference status information table is recorded to be mapped with the identification information of the corresponding optical channel service unit, and

wherein the step (g) includes:

in the case there is no mismatched individual pulse as a result of the comparison or an optical line where a disorder occurs is not recognizable even though the reference OTDR pulse pattern is compared with the obtained OTDR pulse pattern, checking the identification information of a plurality of optical channel service units matched to a single individual pulse, delivering a status request optical signal to each optical channel service unit corresponding to the identification information of the optical channel service units, and receiving a status response optical signal from each optical channel service unit;

measuring an intensity of the status response optical signal and a distance to the optical channel service unit with regard to each of the plurality of optical channel service units by analyzing each received status response optical signal, and comparing the measured distance and optical signal intensity with the distance and optical signal intensity stored in the reference status information table; and

in the case either of the measured distance and optical signal intensity is different from the distance and optical signal intensity stored in the reference status information table over a reference value, identifying an optical channel service unit which has delivered the corresponding optical signal, and determining that a disorder occurs in an optical line region where the optical channel service unit is included.

5. The optical line monitoring method according to claim 3, further comprising:

checking identification information of the optical channel service unit included in the optical line region where a disorder occurs, generating disorder generation information recording the identification information of the optical channel service unit, and reporting the disorder generation information to a manager.

6. An optical line monitoring system, comprising:

a database for storing a reference status information table where identification information of an optical channel service unit is mapped with a distance of the optical channel service unit and storing a reference OTDR (Optical Time Domain Reflectometer) pulse pattern where a plurality of individual pulses are exhibited; and

a pulse matching unit for matching the identification information of each optical channel service unit with the individual pulses exhibited in the reference OTDR pulse pattern so that a proximity order of the individual pulses exhibited in the reference OTDR pulse pattern is identical to a proximity order of the optical channel service units in the reference status information table.

7. The optical line monitoring system according to claim 6, wherein, in the case the number of individual pulses exhibited in the reference OTDR pulse pattern is determined to be not identical to the number of optical channel service units recorded in the reference status information table, the pulse matching unit checks identification information of a plurality of optical channel service units, whose difference in distance is not greater than a threshold value, in the reference status information table, and matches the identification information of the plurality of checked optical channel service units to overlap at a single individual pulse.

8. The optical line monitoring system according to claim 7, further comprising a disorder verifying unit for, in the case an inspection time of the optical line comes, delivering an OTDR pulse to each optical channel service unit, obtaining an OTDR pulse pattern exhibiting a plurality of individual OTDR pulses returned by reflection, checking a concordance rate of the obtained OTDR pulse pattern and the reference OTDR pulse pattern of the database, and verifying a disorder of the optical line based on the concordance rate.

9. The optical line monitoring system according to claim 8, wherein the disorder verifying unit checks a mismatched individual pulse by comparing the individual pulses exhibited in the obtained OTDR pulse pattern with the individual pulses exhibited in the reference OTDR pulse pattern, respectively, and identifying an optical line region where a disorder occurs by checking the identification information of an optical channel service unit matched with the individual pulse.

10. The optical line monitoring system according to claim 8,

wherein, in the reference status information table, an intensity of an optical signal received from each optical channel service unit is recorded to be mapped with the identification information of the corresponding optical channel service unit, and

wherein, in the case the concordance rate is not smaller than the threshold value or an optical line where a disorder occurs is not recognizable even though the reference OTDR pulse pattern is compared with the obtained OTDR pulse pattern, the disorder verifying unit checks the identification information of a plurality of optical channel service units matched at a single individual pulse, delivers a status request optical signal to each optical channel service unit corresponding to the identification information, receives a status response optical signal from the corresponding optical channel service unit, measures an intensity of the status response optical signal and a distance to the optical channel service unit with regard to each of the plurality of optical channel service units by analyzing each status response optical signal, in the case either of the measured distance and optical signal intensity is different from the distance and optical signal intensity stored in the reference status information table over a reference value, identifies an optical channel service unit which has delivered the different optical signal, and determines that a disorder occurs in an optical line region where the optical channel service unit is included.

11. The optical line monitoring system according to claim 8, further comprising a disorder notifying unit for checking identification information of the optical channel service unit included in the optical line region where a disorder occurs, generating disorder generation information recording the identification information of the optical channel service unit, and reporting the disorder generation information to a manager.