Passive optical network maintenance method, an optical network unit, and an optical line terminal

• US 8,655,168 B2
• Filed: 12/12/2006
• Issued: 02/18/2014
• 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
• Primary Examiner(s): DOBSON, DANIEL G
• Application Number:
  US11/609,803
• Publication Number:
  US 20070147836A1
• Time in Patent Office: 2,625 Days
• Field of Search: 398/9, 398/17, 398/22, 398/71, 398/66, 398/1, 398/8, 398/10, 398/15, 398/23, 398/25, 398/38, 398/39, 398/70, 398/100, 398/35, 398/36, 398/24, 398/98, 398/99
• US Class Current: 398/22
• 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 network component comprising:

a processor configured to;

monitor a continuous seizure time for an upstream channel in a passive optical network (PON) comprising a plurality of optical network units (ONUs), wherein the continuous seizure time is obtained by examining the length of time a signal detection circuit detects a signal is present on the upstream channel;

determine whether the continuous seizure time exceeds a predetermined threshold; and

if the continuous seizure time exceeds the predetermined threshold, detect a failed ONU and disable a transmitter in the failed ONU,

wherein the network component is an optical line terminal (OLT), and

wherein a light emitted by the failed ONU during other ONUs'"'"' timeslots has a constant intensity and a constant wavelength.

2. The component of claim 1 wherein detecting the failed ONU comprises:

determining whether one of the ONUs has a seizure time exceeding the predetermined threshold;

determining whether the seizure time can be changed by adjusting a compensation delay in the failed ONU if the seizure time exceeds the predetermined threshold; and

determining that the ONU is the failed ONU if the seizure time cannot be changed by adjusting the compensation delay.

3. The component of claim 1, wherein the processor is further configured to report a status of the PON to a maintenance center.

4. The component of claim 1, wherein the failed ONU is associated with an upstream timeslot, and wherein the failed ONU transmits data during the upstream timeslot and transmits a constant light during at least part of the time outside of the upstream timeslot.

5. The component of claim 1, wherein the failed ONU transmits noise.

6. The component of claim 1, wherein a plurality of the ONUs have failed.

7. The component of claim 1, wherein the failure in the failed ONU is caused by a change in temperature of the failed ONU.

8. The component of claim 1, wherein the failure in the failed ONU is not a constant light emitting state.

9. The component of claim 1, wherein detecting the failed ONU and disabling the transmitter in the failed ONU comprises:

determining whether there is only one registered ONU;

if there is only one registered ONU, determining that the registered ONU is the failed ONU and disabling the transmitter in the failed ONU;

determining whether the ONUs are offline if there is more than one registered ONU; and

if the ONUs are offline, checking each ONU, detecting the failed ONU, and disabling the transmitter in the failed ONU.

10. The component of claim 9, wherein checking each ONU, detecting the failed ONU, and disabling the transmitter in the failed ONU comprises:

broadcasting a message instructing each ONU to disable their transmitter;

determining whether the upstream channel is idle;

if the upstream channel is not idle, sending a pulse signal to the failed ONU, thereby disabling the transmitter in the failed ONU;

selecting one of the ONUs;

sending a control message to the selected ONU providing instructions to enable the transmitter in the selected ONU;

determining whether the seizure time by the selected ONU exceeds the predetermined threshold;

determining that the selected ONU is the failed ONU if the seizure time by the selected ONU exceeds the predetermined threshold;

sending a control message to the failed ONU instructing the failed ONU to disable the failed ONU'"'"'s transmitter power supply; and

sending a control message to the non-failed ONUs instructing the non-failed ONUs to enable their transmitters.

11. The component of claim 10, wherein the continuous seizure time is monitored periodically at a predefined interval.

12. The component of claim 10, wherein the processor is further configured to:

determine whether the selected ONU is registered; and

determine that the selected ONU is the failed ONU if the selected ONU is not registered.

13. The component of claim 10, wherein an optical module (OM) outputs the pulse signal.

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

15. The component of claim 10, wherein determining whether the seizure time by the selected ONU exceeds the predetermined threshold comprises determining whether the seizure time can be changed by adjusting a compensation delay in the ONU.

16. The component of claim 15, wherein the predetermined threshold is a range of upstream channel timeslots assigned to the ONU.

17. An optical line terminal (OLT) comprising:

an optical module (OM); and

a troubleshooting module coupled to the OM, wherein the troubleshooting module is configured to;

monitor a fault status indicated by a continuous seizure time of an upstream channel obtained by examining the length of time a signal detection circuit detects a signal is present on the upstream channel;

determine whether the continuous seizure time exceeds a predetermined threshold;

locate a faulty optical network unit (ONU); and

solve a fault, wherein the faulty ONU transmits only noise.

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

a fault monitoring sub-module coupled to the OM, wherein the fault monitoring sub-module is configured to monitor the fault status and output a fault indication signal;

a fault solving sub-module configured to determine the faulty ONU using the fault indication signal and solve the fault; and

a fault information reporting sub-module configured to report the information about the faulty ONU to a maintenance center.

19. The OLT of claim 18 further comprising a service processing module (SPM) coupled to the OM and the fault solving sub-module, wherein the SPM is configured to receive the related fault solving instruction generated by the fault solving sub-module and transmit the instruction via the OM.

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

a signal detection (SD) wiring terminal coupled to the fault monitoring sub-module, wherein the SD wiring terminal is configured to output a detection signal indicating the arrival of an optical signal; and

a disabling signal terminal coupled to the fault solving sub-module, wherein the disabling signal terminal is configured to receive a pulse disabling signal from the fault solving sub-module.