Performance monitoring in passive optical networks
View Patent ↗One embodiment provides a system for performance monitoring in a passive optic network (PON). The system includes an optical line terminal (OLT) and an optical network unit (ONU). The OLT includes an optical transceiver configured to transmit optical signals to and receive optical signals from the ONU, and a performance monitoring mechanism configured to monitor performance of the PON based on received optical signals.
1. An optical line terminal (OLT), comprising:
an optical transceiver; and
a performance-monitoring mechanism configured to:
generate a logical link identifier (LLID) that is dedicated to performance monitoring,
grant a transmission window corresponding to the LLID to respective optical network units (ONUs) in a plurality of ONUs,
assign the LLID to each respective ONU in the plurality of ONUs,
measure, in turn, optical signals received from the respective ONUs during their respective transmission windows, and
monitor a performance of the respective ONUs based on the measured optical signals.
2. The OLT of claim 1 , wherein each ONU of the respective ONUs comprises:
a transmitter; and
a switch, coupled to the transmitter, configured to electrically disconnect the transmitter based on an instruction received from the OLT.
3. The OLT of claim 1 , wherein the performance-monitoring mechanism comprises:
an optical power monitor configured to measure, in turn, optical power of the optical signals received from the respective ONUs.
4. The OLT of claim 1 , wherein each of the respective ONUs comprises:
a forward-error-correction (FEC) mechanism.
5. The OLT of claim 4 , wherein the performance-monitoring mechanism is further configured to monitor the performance of the respective ONUs based on FEC statistics associated with the FEC mechanism.
6. The OLT of claim 5 , wherein the performance-monitoring mechanism is configured to generate a separate bit sequence to extract the FEC statistics for the respective ONUs.
7. The OLT of claim 1 , wherein the performance-monitoring mechanism is further configured to enable a forward-error-correction (FEC) mechanism on the OLT in response to determining that an ONU in the plurality of ONUs is aging.
8. The OLT of claim 1 , wherein the LLID is not used for regular data transmissions.
9. The OLT of claim 1 , wherein the performance-monitoring mechanism is further configured to:
measure a transmission power of an ONU in the plurality of ONUs; and
determine, based on a comparison between the measured transmission power and an ideal transmission power of the ONU, whether the ONU is aging.
10. The OLT of claim 1 , wherein the performance-monitoring mechanism is further configured to:
measure a transmission power of an ONU in the plurality of ONUs; and
determine, based on a comparison between the measured transmission power and a previously measured transmission power of the ONU, whether the ONU is aging.
11. The OLT of claim 1 , wherein the performance-monitoring mechanism is further configured to:
measure a transmission power of an ONU in the plurality of ONUs; and
determine, based on the measured transmission power, whether the transmission power is decreasing over time.
12. A method for monitoring a performance of a passive optical network (PON) including an optical line terminal (OLT) and a plurality of optical network units (ONUs), comprising:
generating a logical link identifier (LLID) that is dedicated to performance monitoring;
granting a transmission window corresponding to the LLID to respective ONUs in the plurality of ONUs;
assigning, using the OLT, the LLID to each respective ONU in the plurality of ONUs;
measuring, in turn, optical power of signals received from the respective ONUs during their respective transmission windows; and
monitoring the performance of the PON based on the measured optical power.
13. The method of claim 12 , wherein the measuring the optical power of the signals comprises:
monitoring the optical power of the signals within a sampling period arbitrarily aligned within the transmission window.
14. The method of claim 13 , wherein the measuring the optical power of the signals comprises:
monitoring the optical power of the signals beginning at a start time of the sampling period that aligns with a beginning of the transmission window.
15. The method of claim 12 , wherein the measuring the optical power of the signals comprises:
monitoring the optical power of the signals beginning at a start time of the sampling period that aligns with an end of the transmission window.
16. The method of claim 12 , further comprising:
performing forward-error-correction (FEC) to the signals received from the respective ONUs;
obtaining FEC statistics specific for the respective ONUs; and
determining respective performances of the respective ONUs based on the FEC statistics.
17. The method of claim 16 , further comprising:
generating a separate bit sequence to extract the FEC statistics.
18. The method of claim 12 , further comprising:
monitoring line coding error statistics to facilitate the performance monitoring.
19. An optical line terminal (OLT) for facilitating performance monitoring in a passive optical network (PON), the OLT comprising:
an optical transceiver configured to transmit optical signals to and receive optical signals from a plurality of optical network units (ONUs); and
a performance-monitoring mechanism configured to:
generate a logical link identifier (LLID) that is dedicated to performance monitoring;
grant a transmission window corresponding to the LLID to respective ONUs in the plurality of ONUs,
assign the LLID to each respective ONU in the plurality of ONUs,
measure idle power from each of the respective ONUs in turn, and
determine, based on the measured idle power, whether an ONU in the plurality of ONUs is leaking power.