PON ONU Power Saving Mode with Periodic Wake-Up
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Solution Overview
Problem
In PON systems, disconnecting an ONU when no upstream data is transmitted leads to inefficient power usage and difficulty in detecting communication abnormalities, as the discovery process for re-registration is cumbersome and fails to detect link issues promptly.
Innovation Solution
Implementing a power-saving mode where ONUs notify the OLT of their transition to a sleep state, allowing for intermittent communication and failure detection while maintaining a link, thereby reducing power consumption and enabling early detection of communication failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ONU is kept in a constant communication state to enable round-trip time measurement, then measurement capability is maintained, but power consumption increases
Solution Approach 1:
The patent implements periodic wake-up of the ONU at predetermined intervals to perform round-trip time measurements. The ONU transitions between sleep mode and active state periodically, allowing measurements to be conducted at specific intervals rather than continuously. This resolves the contradiction by enabling measurement capability while significantly reducing power consumption through intermittent operation.
2Productivity
If the OLT disconnects the ONU when no upstream data is transmitted, then bandwidth efficiency is improved, but failure detection capability deteriorates
Solution Approach 1:
The patent establishes a predetermined periodic wake-up schedule in advance before the ONU enters sleep mode. This preliminary action ensures that the ONU will automatically wake up at specified intervals to maintain link connectivity and enable failure detection, while allowing bandwidth to be efficiently released during sleep periods when no measurements are needed.
3Use of energy by moving object
If the ONU enters sleep mode to reduce power consumption, then energy efficiency is improved, but link maintenance capability deteriorates
Solution Approach 1:
The patent implements dynamic state transitions where the ONU alternates between sleep mode and active state according to a predetermined schedule. The ONU dynamically adjusts its operational state based on timing conditions, waking up at predetermined intervals to maintain link stability while spending the majority of time in low-power sleep mode. This dynamic approach resolves the contradiction by making link maintenance capability time-dependent rather than constant.
Data Source
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AI summary
The ONU 10 includes the optical transceiver 14 capable of an operation in a power-saving mode in which power consumption is reduced by stopping transmission while continuing reception, and the control device 11 that controls to tentatively validate transmission of the optical transceiver and outputs a response signal when a control signal is received from the OLT during an operation in a power-saving state. Moreover, the OLT includes the control device 2 that allocates a transmission bandwidth to the ONU even while the optical transceiver of the ONU operates in a power-saving mode and stops transmission and determines whether a communication failure occurs or the ONU is in operation in a power-saving mode based on the response signal received by a transceiver of the OLT.