Optical Transmitter Disabling Device for Passive Optical Networks

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Solution Overview

Problem

In passive optical networks, rogue Optical Network Termination (ONT) nodes can disrupt communication by transmitting continuous or unsynchronized light, impairing upstream communication for other nodes, as they do not adhere to their allocated time slots, posing a risk of malicious interference.

Innovation Solution

An optical transmitter disabling device integrated into the ONT node, comprising a monitoring module and a disabling module, which interrupts the activation signal to the optical transmitter if it detects activity outside a predetermined time interval, ensuring the transmitter only operates within its designated slot, thus preventing rogue behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the optical transmitter is allowed to transmit continuously or outside allocated time slots, then the transmitter can maintain simple operation and high bandwidth availability, but it disrupts upstream communication for other optical network termination nodes in the passive optical network

Engineering Contradiction:
Improvebandwidth availabilityVSAvoidupstream communication reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements periodic time-division multiple access (TDMA) slots for upstream communication, where each optical network termination node is allocated specific time windows for transmission. The monitoring module enforces these periodic transmission intervals, ensuring that nodes only transmit during their designated slots rather than continuously, thereby preventing communication disruptions while maintaining efficient bandwidth utilization across the network.

Inventive Principle:
Principle #19Periodic action

2Reliability

If the optical transmitter is monitored and controlled to transmit only within predetermined time intervals, then network reliability is improved, but the device complexity increases due to the monitoring and disabling modules

Engineering Contradiction:
Improvenetwork communication reliabilityVSAvoidtransmitter control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The monitoring module is integrated directly into the optical network termination node itself, enabling it to autonomously monitor its own transmitter activation status and enforce compliance with TDMA slot allocations. This self-service approach eliminates the need for complex external monitoring infrastructure, as each node independently regulates its own transmission behavior based on received synchronization signals from the optical line terminal.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements feedback control where the monitoring module continuously compares the actual transmitter activation status against the expected TDMA slot timing. When deviations are detected (such as continuous transmission or transmission outside allocated slots), the disabling module receives feedback signals to interrupt the activation signal, thereby correcting the behavior and maintaining synchronization with the network protocol.

Inventive Principle:
Principle #23Feedback

3Reliability

If the disabling module interrupts the activation signal to prevent rogue transmission, then network security is improved, but the ease of operation decreases due to automatic disabling of legitimate transmitters

Engineering Contradiction:
Improvenetwork securityVSAvoidtransmitter operation simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system establishes predetermined time intervals and TDMA slot allocations in advance through synchronization signals from the optical line terminal. These preliminary timing parameters are configured before transmission begins, allowing the monitoring module to automatically determine whether transmitter activation occurs during legitimate time slots or rogue periods. This pre-configuration eliminates the need for real-time human judgment, preventing both rogue transmissions and false disabling of legitimate nodes.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2294727B1Transmitter disabling device
Publication Date: 2013.06.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2294727B1 patent drawingFigure 1~3
  • EP2294727B1 patent drawingFigure 4~5c
  • EP2294727B1 patent drawingFigure 6

AI summary

An optical transmitter disabling device for controlling an optical transmitter (14), particularly of an optical network termination node (3, 4, 5, 6) of a passive optical network (1 ) comprising a monitoring module (11 ) and a disabling module (12), the monitoring module (11 ) being adapted to determine at least when the optical transmitter (14) is active, the disabling module (12) being adapted to be connected to an activation input (16) of the optical transmitter (14) and wherein the disabling module (12) is adapted to interrupt an activation signal to the optical transmitter (14) at least when the monitoring module (11 ) determines that the optical transmitter (14) is active outside of a predetermined time interval.