PON Station Device Abnormal Light Emission Detection

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Solution Overview

Problem

Conventional PON systems face challenges in accurately identifying the source of abnormal light emission among ONUs, leading to erroneous shutdowns of normal ONUs during temporary irregular light emission issues.

Innovation Solution

A station-side device with an optical transmission/reception unit, abnormal-light-emission detection unit, and optical-communication control unit that monitors optical signals, selectively stops signal transmission from ONUs to determine if abnormal light emission is resolved, thereby accurately specifying the causative ONU.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional ONU identification method is used, then the system can detect abnormal light emission, but normal ONUs may be erroneously shut down during temporary irregular light emission

Engineering Contradiction:

Improveaccuracy of ONU identificationVSAvoiderroneous shutdown of normal ONUs

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system segments the abnormal light emission detection process into multiple stages: initial detection of abnormal emission, sequential isolation testing of individual ONUs, and confirmation of the causative ONU. This segmentation allows the system to identify the specific problematic ONU rather than erroneously shutting down multiple normal ONUs.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary isolation testing by sequentially stopping optical signal transmission from each ONU before making a final determination. This preliminary action prevents premature shutdown of normal ONUs by first confirming which specific ONU causes the abnormal emission through controlled testing.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If sequential testing of each ONU is performed to identify the causative device, then accurate identification is achieved, but system response time increases

Engineering Contradiction:

Improveprecision of causative ONU identificationVSAvoidtime for identifying causative ONU

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system implements periodic action by sequentially and systematically testing each ONU in turn with controlled optical signal transmission. This structured periodic approach ensures comprehensive identification of the causative ONU while optimizing the testing sequence to minimize overall identification time.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS11916659B2Station-side device, optical communication system, and search method

Publication Date: 2024.02.27 MITSUBISHI ELECTRIC CORP

AI summary

An OLT 110 includes an optical transmission/reception unit 111 to transmit and receive optical signals by time division; an abnormal-light-emission detection unit 112 to monitor the received optical signals, and detect a state in which the optical signals are being received for a predetermined period or longer as abnormal light emission in which the optical signals from one or more of the ONUs 130 are not received; an optical-communication control unit to sequentially select an ONU 130 one at a time from the plurality of ONUs 130 other than the one or more ONUs 130 as a target ONU 130, test whether the abnormal light emission is resolved by stopping transmission of the optical signal from each target ONU 130, and, if the abnormal light emission is resolved, specifies the target ONU 130 being tested as an ONU 130 that is a source of the abnormal light emission.