PON ONU Power Saving via OLT Data Absence Notification

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Solution Overview

Problem

In PON systems, ONUs consume unnecessary power when in a power-saving state due to the inability to recognize the absence of downstream data, leading to continued buffer refresh and data processing readiness, even when no data is present.

Innovation Solution

The PON system implements a power-saving method where the OLT requests transition to a downstream power-saving state for ONUs when no downstream data is detected, allowing components involved in downstream data processing to enter a power-saving state, and only returning to normal when data is anticipated, thereby reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the ONU enters power-saving state to reduce power consumption, then power consumption is reduced, but the ONU cannot recognize the presence or absence of downstream data and must return the buffer to normal state at refresh time, causing unnecessary power consumption

Engineering Contradiction:
Improvepower consumption of ONUVSAvoidunnecessary power consumption during buffer refresh
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The OLT performs preliminary action by notifying the ONU in advance about the absence of downstream data before the ONU enters power-saving state. This allows the ONU to extend its power-saving state beyond the normal refresh time without worrying about missing data, thereby eliminating unnecessary buffer refresh operations and reducing power consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The OLT provides feedback to the ONU about downstream data status through specific notification messages. This feedback mechanism allows the ONU to make informed decisions about extending its power-saving state, optimizing power consumption by avoiding unnecessary wake-ups and buffer refreshes when no data is present.

Inventive Principle:
Principle #23Feedback

2Reliability

If the ONU maintains normal state to recognize downstream data presence, then data reception capability is maintained, but power consumption increases unnecessarily during periods without data communication

Engineering Contradiction:
Improvedata reception capabilityVSAvoidpower consumption during idle periods
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The OLT takes preliminary action by sending notification messages to the ONU about the absence of downstream data before the ONU needs to wake up. This allows the ONU to confidently enter and extend power-saving states without compromising data reception capability, as it has advance knowledge of the data status.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ONU dynamically adjusts its operational state based on received notifications. When notified of no downstream data, the ONU extends its power-saving state; when data is expected, it maintains or returns to normal state. This dynamic adaptation optimizes the balance between power consumption and data reception capability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2469786B1PON system, subscriber-end terminal apparatus, station-end terminal apparatus and power saving method
Publication Date: 2020.11.04 MITSUBISHI ELECTRIC CORP
  • EP2469786B1 patent drawingFigure 1
  • EP2469786B1 patent drawingFigure 2
  • EP2469786B1 patent drawingFigure 3

AI summary

In the PON system, the ONU 10 includes the receive buffer 13 that stores therein a signal in a downstream direction transmitted from the OLT 1 and the PON control unit 11 that controls transition to a power-saving state and transition to a normal state for the reception buffer 13, the OLT 1 includes the transmission buffer 4 that stores transmission data to be transmitted to the ONU 10 and the PON control unit that transmits the downstream power-saving-state transition request that requests the ONU 10 to transition to the downstream power-saving state when it is determined that transmission data addressed to the ONU 10 is not present in the transmission buffer 4, and the PON control unit 11 sets the reception buffer 13 to a power-saving state for a predetermined downstream sleep time requested based on the downstream power-saving-state transition request.