ONU Deep-Sleep Wake-Up with Photodiode Signal Detection
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Solution Overview
Problem
Existing passive optical network (PON) systems face challenges in efficiently powering down optical network units (ONUs) for energy savings while ensuring timely wake-up for incoming calls and emergency messages, as current wake-up mechanisms are limited to local activation and do not allow remote triggering from the optical line terminal (OLT).
Innovation Solution
Implementing a system where the ONU is set into a deep sleep mode with a powered-off data processing unit and an active photodiode, allowing the OLT to vary downstream signal power to detect changes and activate the ONU, while the OLT varies downstream signal power to wake up specific ONUs based on service type or emergency needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the ONU is set into asleep mode with hardware components disabled to save power, then power consumption is reduced, but the ONU cannot be remotely woken up by the OLT and incoming calls/messages cannot be delivered in time
Solution Approach 1:
The ONU receiver is divided into two independent parts: a low-power photodiode that remains active during deep sleep mode to detect wake-up signals, and the main data processing and control unit that is powered off. This segmentation allows the system to maintain minimal power consumption while preserving the ability to be remotely woken up by the OLT through optical signal detection.
2Reliability
If the ONU switches to sleep aware state to enable receiving and sending modules, then wake-up capability is achieved, but power consumption increases significantly
Solution Approach 1:
Instead of switching the entire receiver to an enabled state for wake-up functionality, only the photodiode is kept active with high sensitivity to detect optical wake-up signals from the OLT. The main data processing unit remains powered off, achieving wake-up capability with minimal power consumption by applying different operational states to different components.
3Reliability
If the OLT varies downstream signal power to wake up ONUs, then remote wake-up capability is achieved, but signal power variation may affect other active ONUs
Solution Approach 1:
The OLT dynamically adjusts the downstream signal power only for specific time intervals targeting ONUs in deep sleep mode, while maintaining normal signal levels for active ONUs. The photodiode in deep sleep mode is designed with high sensitivity to detect these dynamic power variations, enabling selective wake-up without interfering with normal operations of active units.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Achieves significant power savings by powering down major transceiver components while enabling remote wake-up of ONUs, ensuring timely response to calls and messages with minimal modifications to existing ONU and OLT infrastructure.
Implementation Method 1
a photodiode of the ONU is active, and wherein the photodiode is configured to receive a downstream signal from the OLT and detect a change in an average power based on the downstream signal
Data Source
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AI summary
The present invention discloses an apparatus for use in an Optical Network Unit, ONU, communicatively connected to an Optical Line Terminal, OLT, comprising means for: setting the ONU into a deep sleep mode, wherein, in the deep sleep mode, a data processing and control unit of the ONU is powered off and a photodiode of the ONU is active, and wherein the photodiode is configured to receive a downstream signal from the OLT and the data processing and control unit is configured to process downstream signal received from the OLT; detecting a change in an average power based on the downstream signal received by the photodiode from the OLT; activating the data processing and control unit of the ONU based on the detected change. The present invention discloses an apparatus for use in an OLT communicatively connected to a plurality of ONUs, comprising means for: varying an average output power of a PON downstream signal for a predetermined duration based on a determination of waking up at least one ONU from a deep sleep mode.