Tellabs Petaluma, Inc.

Tellabs Pataluma, Inc.

David A DeLew

Robert S Larvenz

Paul Edwin O'Connor

Joseph Golja

Manic C Steyn

Nathan D Knuth

Weijun Li

Joseph D Miguel

Ryan D Houlgate

Vinita Gupta

A method and corresponding apparatus for diagnosing problems on a time division multiple access (TDMA) optical distribution network (ODN) is provided. An example method may include: (i) measuring no-input signal power level on a communications path configured to carry upstream communications between multiple optical network terminals (ONTs) and an optical line terminal (OLT) in a passive optical network (PON) at a time no upstream communications are on the communications path from the ONTs to the OLT; (ii) comparing the measured no-input signal power level to a threshold; and (iii) generating a notification in an event the threshold is exceeded. Through the use of this method, faults in optical transmitters, such as bad solder joints, can be determined. Such faults may cause errors in parameters, such as ranging or normalization parameters, associated with communications. By determining the faults, the time required to resolve communications errors can be reduced.

Method and apparatus for diagnosing problems on a time division multiple network access (TDMA) optical distribution network (ODN)

Component malfunctions in passive optical networks (PON) can increase bit error rates and decrease signal-to-noise ratio of communications signals. These faults may cause the receivers of the signals, either the optical line terminal (OLT) or optical network terminals (ONTs), to experience intermittent faults and/or may result in misinterpreted commands that disrupt other ONT's communication, resulting in a rogue ONT condition. Existing PON protocol detection methods may not detect these types of malfunctions. An embodiment of the present invention identifies faults in a PON by transmitting a test series of data patterns via an optical communications path from a first optical network node to a second optical network node. The test series is compared to an expected series of data patterns. An error rate may be calculated as a function of the differences between the test series and expected series. The error rate may be reported to identify faults in the PON. Through use of the embodiment, network faults can be identified and optionally automatically corrected, saving a network service provider from expending technician time and maintaining an operating state of the network.

Method and apparatus for correcting faults in a passive optical network

A method and corresponding apparatus is disclosed for determining a particular Optical Network Terminal (ONT) in a Passive Optical Network (PON) is malfunctioning by sending a continuous stream of light up a shared fiber, which results in adversely affecting communications between the ONT and an Optical Line Terminal (OLT). The example embodiment verifies the failure is due to a faulty optical transmitter in the ONT and not a different network fault, such as a fiber optic line cut or power outage. Through the use of the example embodiment, a service provider can determine in an automated manner which specific ONT of a PON is malfunctioning.

Methods and apparatus for identifying a passive optical network failure

Jitter in a clock signal can cause communications faults in communications networks, such as in networks in which downstream nodes use recovered clock signals as timing for upstream communications. An embodiment of the present invention detects and compensates for jitter in a network by recovering a reference clock associated with communications signals between nodes, such as an Optical Line Terminal (OLT) and Optical Network Terminal (ONT) in a Passive Optical Network (PON). A local clock is synchronized with the reference clock. Jitter induced faults may be detected and compensated for by increasing the synchronization rate, then decreasing the synchronization rate until jitter induced faults begin to occur. A loss or change in a rate of communications errors occurring as a function of the synchronization rate may be monitored and reported to a system operator. Compensating for jitter by adjusting the synchronization rate provides for robust communications between network nodes.

Method and apparatus for detecting and compensating for jitter in a communications network

Growing community of inventors

Rohnert Park, CA, United States of America

David A DeLew