PON OLT Control for Flexible ONU Power Saving

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Solution Overview

Problem

In PON systems, existing power saving techniques either increase latency or fail to reduce power consumption effectively, as they do not allow for flexible control of power saving periods, leading to inefficient use of resources during periods of low data communication.

Innovation Solution

A communication system where the OLT generates control signals to manage power saving operations in ONUs, allowing for different idle periods and modes, enabling selective power saving by halting either the transmitter, receiver, or both, based on specified power saving periods, thereby reducing power consumption without compromising latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the ONU maintains a transmissible state at all times for roundtrip time measurement and keep-alive communication, then measurement precision and communication reliability are improved, but power consumption increases

Engineering Contradiction:
Improveroundtrip time measurement precisionVSAvoidONU power consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic power saving operations where the ONU alternates between active and sleep states. The OLT control unit generates control signals that specify idle periods, during which the ONU halts its optical transmitter and/or receiver. This periodic activation and deactivation allows the system to maintain measurement capabilities when needed while reducing power consumption during low-activity periods, directly resolving the contradiction between continuous operation and power saving.

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If a power saving period is provided for the ONU, then power consumption is reduced, but the period during which the terminal device cannot respond becomes long, increasing delay time

Engineering Contradiction:
ImproveONU power consumptionVSAvoidcommunication delay
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent makes the idle period dynamic and adjustable through control signals from the OLT. The OLT control unit can modify the idle period duration based on communication conditions, allowing the system to adapt between longer power-saving periods when latency is tolerable and shorter response periods when low latency is required. This dynamic adjustment resolves the fixed trade-off between power saving and delay.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the idle period parameter based on communication requirements. The OLT control unit generates control signals that specify different idle period durations, allowing the system to optimize between power consumption and delay by adjusting this key parameter. When low latency is prioritized, the idle period is shortened; when power saving is prioritized, the idle period is extended, thus resolving the contradiction through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the optical transmitter and receiver are continuously operated, then communication reliability is improved, but power consumption increases during periods of low data communication

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidONU power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic operation where the optical transmitter and receiver are activated only during necessary communication periods and halted during idle periods. The OLT control unit coordinates these periodic operations to ensure reliability is maintained when data communication is needed while achieving power savings during low-activity periods, resolving the contradiction between continuous operation and power saving.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2566112B1Communication system, station side communication device, user side communication device, communication method, and control device
Publication Date: 2019.06.26 MITSUBISHI ELECTRIC CORP
  • EP2566112B1 patent drawingFigure 1
  • EP2566112B1 patent drawingFigure 2
  • EP2566112B1 patent drawingFigure 3

AI summary

An OLT 1 includes an OLT control unit 2 that generates a control signal for controlling a power saving operation of an ONU 10-1 by specifying a different idle period with respect to a first power saving operation in which an optical receiver 142 is operated while an optical transmitter 141 of the ONU 10-1 is controlled to a power saving state and a second power saving operation for controlling the optical transmitter 141 and the optical receiver 142 to the power saving state, and a station-side transmitter that transmits the control signal generated by the OLT control unit 2 to the ONU. The ONU 10-1 includes an ONU control unit 11 that receives the control signal via the optical receiver 142 to selectively perform the first power saving operation and the second power saving operation based on the idle period specified by the control signal.