Passive Optical Network Maintenance Method, an Optical Network Unit, and an Optical Line Terminal

• US 20070147836A1
• Filed: 12/12/2006
• Published: 06/28/2007
• Est. Priority Date: 12/23/2005
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Dong, Yinghua
• Granted Patent: US 8,655,168 B2
• Time in Patent Office: Days
• US Class Current: 398/71
• CPC Class Codes: H04B 10/073 using an out-of-service signal H04B10/071 takes precedence
• CPC Class Codes: H04B 10/0771 Fault location on the transmission path
• CPC Class Codes: H04B 10/0773 Network aspects, e.g. central monitoring of transmission parameters
• CPC Class Codes: H04B 10/0791 Fault location on the transmission path
• CPC Class Codes: H04B 10/0793 Network aspects, e.g. central monitoring of transmission parameters
• 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 2011/0081 Fault tolerance; Redundancy; Recovery; Reconfigurability

Abstract

The present disclosure relates to a passive optical network (PON) and provides a method for maintaining the PON, the optical network unit (ONU), and the optical line terminal (OLT) to solve the problem of the ONU being in a constant light emitting state. The method of the present disclosure allows the OLT to determine whether the continuous seizure time of an upstream channel exceeds the preset threshold, and if so, detect the failed ONU that continuously seizes the upstream channel and use a control message or control signal to instruct the failed ONU to turn off power supply to its transmitting circuit.

Claims

1. A method for maintaining a passive optical network (PON) comprising an optical line terminal (OLT) and at least one optical network unit (ONU), wherein the method comprises:

A. monitoring, by the OLT, a continuous seizure time for an upstream channel;

B. determining whether the continuous seizure time exceeds a preset threshold, and if so, proceeding to process C;

otherwise, returning to process A; and

C. detecting a failed ONU that continuously seizes the upstream channel, and instructing the failed ONU to turn off the failed ONU'"'"'s transmitting circuit power supply.

2. The method of claim 1 wherein detecting the failed ONU that continuously seizes the upstream channel in the process C comprises:

determining which of the ONUs is continuously seizing the upstream channel for a length of time exceeding the preset threshold; and

determining whether the continuous seizure time of the upstream channel can be changed by adjusting the seizing ONU'"'"'s compensation delay, and if so, determining that the seizing ONU is normal;

otherwise, determining that the seizing ONU is the failed ONU.

3. The method of claim 1 wherein the process C comprises:

C1. determining whether there is only one registered ONU and if so, marking the registered ONU as failed, and instructing the failed ONU to turn off the failed ONU'"'"'s transmitting circuit power supply;

otherwise, proceeding to process C2;

C2. determining whether all of the ONUs are offline, and if so, proceeding to process C3;

otherwise, confirming that the network is normal; and

C3. checking each ONU, determining the failed ONUs, and instructing the failed ONUs to turn off the failed ONUs'"'"' transmitting circuit power supplies.

4. The method of claim 3 wherein the process C3 comprises:

C301. broadcasting a control message that gives instructions to turn off the failed ONUs'"'"' transmitting circuit power supply;

C302. determining whether the upstream channel is idle, and if so, proceeding to process C304;

C303. sending a pulse signal instruction to the ONUs instructing the ONUs to turn off the ONUs'"'"' transmitting circuit power supply;

C304. selecting one of the ONUs to be a to-be-checked ONU;

C305. sending a control message to the to-be-checked ONU providing instructions to turn on the to-be-checked ONU'"'"'s transmitting circuit power supply;

C306. determining whether the continuous seizure time by the to-be-checked ONU exceeds the preset threshold;

C307. marking the to-be-checked ONU as the failed ONU;

C308. sending a control message to the failed ONU instructing the failed ONU to turn off the failed ONU'"'"'s transmitting circuit power supply; and

C309. determining whether there are any unchecked ONUs, and if so, selecting a next ONU to be checked from the unchecked ONUs;

otherwise sending a control message to all non-failed ONUs instructing the non-failed ONUs to turn on the non-failed ONUs'"'"' transmitting circuit power supply.

5. The method of claim 4 wherein the process C306 further comprises:

when the continuous seizure time of the upstream channel by the to-be-checked ONU exceeds the preset threshold, determining whether the continuous seizure of the upstream channel can be changed by adjusting the compensation delay of the ONU.

6. The method of claim 5 wherein the preset threshold refers to the range of upstream channel timeslots assigned to the ONU by the OLT.

7. The method of claim 4 wherein the OLT achieves periodic monitoring by executing the process A at a predefined interval, by returning to the process A in the process C2 when confirming that the system is normal or returning to the process A in the process C309 after instructing the non-failed ONUs to turn on the non-failed ONUs'"'"' transmitting circuit power supply.

8. The method of claim 4, wherein there is an operation between the processes C305 and C306 comprising:

checking whether the to-be-checked ONU is registered, and if so, then proceeding to the process C306;

otherwise marking the to-be-checked ONU as the failed ONU.

9. The method of claim 4 wherein in the process C303, the OLT causes an optical module (OM) to output the pulse signal by inputting a pulse to the OM to transmit an enabling/disenabling signal.

10. The method of claim 4 wherein the control message is defined by extending the control message, an operation, administration, and maintenance (OAM) message predefined in the PON, or is defined according to the existing protocol.

11. The method of claim 1 wherein the process C further comprises the process of the OLT reporting information about the PON functioning normally or about the failed ONU to the maintenance center.

12. An optical network unit (ONU) comprising an optical module (OM), wherein the ONU further comprises:

a transmitting circuit power supply module connected to the OM for supplying power to the transmitting circuit of the OM; and

a transmitting circuit power supply control module connected to the transmitting circuit power supply module for turning on/off the transmitting circuit power supply module according to an external power supply control instruction.

13. The ONU of claim 12 wherein the ONU further comprises:

a service processing module (SPM), which connects the OM to the power supply control module, for receiving the external power supply control instruction and forwarding the external power supply control instruction to the transmitting circuit power supply control module; and

a receiving circuit power supply module connected to the OM for supplying power to the receiving circuit of the OM.

14. The ONU of claim 13 wherein the SPM further comprises:

an instruction recognition sub-module for identifying the external power supply control instruction and forwarding the external power supply control instruction to the power supply control module.

15. The ONU of claim 14 wherein the transmitting circuit power supply control module further comprises:

an instruction resolution sub-module connected to the instruction recognition sub-module for resolving the external power supply control instruction; and

an instruction execution sub-module, which connects the instruction resolution sub-module with the receiving circuit power supply module, for generating a corresponding control signal according to the resolution results and outputting the signal to the transmitting circuit power supply module.

16. The ONU of claim 15 wherein

the OM comprises a signal detection (SD) wiring terminal for outputting a detection signal to detect whether there is an incoming optical signal;

and

the transmitting circuit power supply control module further comprises a pulse signal monitoring sub-module, which connects the SD wiring terminal with the instruction execution sub-module, and instructs the instruction execution sub-module to turn off the transmitting circuit power supply module when the detection signal output from the SD terminal is a predefined pulse signal.

17. An optical line terminal (OLT) comprising an optical module (OM), wherein the OLT further comprises:

a troubleshooting module connected to the OM for monitoring the fault status indicated by a continuous seizure time of an upstream channel connected to the OM, determining whether the continuous seizure time exceeds a preset threshold, locating the fault source, and solving the fault.

18. The OLT of claim 17 wherein the troubleshooting module comprises:

a fault monitoring sub-module connected to the OM for monitoring the fault status and outputting a fault indication signal;

a fault solving sub-module that determines the fault source based on the fault indication signal and solves the fault; and

a fault information reporting sub-module for reporting the information about the detected fault source to a maintenance center.

19. The OLT of claim 18 wherein the OLT further comprises a service processing module (SPM) connecting the OM with the fault solving sub-module, for receiving the related fault solving instruction generated by the fault solving sub-module, and transmitting the instruction via the OM.

20. The OLT of claim 18 wherein the OM comprises:

a signal detection (SD) wiring terminal connected to the fault monitoring sub-module, and for outputting a detection signal indicating the arrival of an optical signal; and

an enabling/disenabling signal wiring terminal connected to the fault solving sub-module, and for receiving the pulse enabling/disenabling signals from the fault solving sub-module.