Optical Line Terminal Transmitter Control for In-Service Power Reduction

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Solution Overview

Problem

Existing passive optical networks (PONs) face challenges in accurately predicting and managing power consumption of optical line terminals (OLTs) due to unexpected changes in deployment conditions, leading to excessive power consumption and limited adaptability, with manual adjustments disrupting service and being labor-intensive.

Innovation Solution

An OLT with adjustable transmitter and receiver settings, controlled by a controller, dynamically adjusts power consumption based on PON deployment information to maintain minimal channel quality, allowing for in-service power optimization without disrupting service.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If manual swapping of OLT optics is performed to adjust power consumption, then power consumption can be reduced or increased, but service disruption occurs and labor intensity increases

Engineering Contradiction:
ImproveOLT power consumptionVSAvoidService continuity and operational simplicity
Core Design Contradiction:
Use of energy by stationary objectVSEase of operation

Solution Approach 1:

The patent implements dynamic adjustment of transmitter settings (laser bias current, modulation amplitude) to change optical output power levels in real-time without physical hardware changes. This allows the OLT to adapt its power consumption to actual network conditions while maintaining continuous service operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (transmitter settings) rather than physical components. By adjusting bias current and modulation depth, the optical output power is modified dynamically, achieving power consumption optimization without service disruption or manual intervention.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If fixed optical budget classes with predetermined output power are used, then device complexity is reduced, but adaptability to changing deployment conditions is limited

Engineering Contradiction:
ImproveAdaptability to deployment changesVSAvoidTransmitter control complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of fixed optical budget classes, the system employs dynamic transmitter control that can adjust output power continuously. The controller modifies transmitter settings based on monitored channel quality metrics, enabling adaptation to varying deployment conditions such as temperature changes, component aging, or unexpected network topology variations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a feedback mechanism where channel quality metrics are continuously monitored and used to adjust transmitter settings. This closed-loop control enables the OLT to maintain optimal performance while adapting to changing conditions, resolving the contradiction between adaptability and complexity through intelligent control.

Inventive Principle:
Principle #23Feedback

3Reliability

If excess margin is provided in the PON to ensure reliability, then network reliability is improved, but power consumption increases

Engineering Contradiction:
ImproveNetwork reliabilityVSAvoidOLT power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The system dynamically adjusts the operating margin by continuously monitoring channel quality and adapting transmitter settings accordingly. When conditions are favorable, the margin is reduced to lower power consumption; when conditions deteriorate, the margin is increased to maintain reliability, thus optimizing the trade-off between reliability and power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The transmitter settings are adjusted as a function of monitored channel conditions. By changing bias current and modulation parameters based on actual performance metrics, the system maintains the minimum required margin for reliability while minimizing excess margin that would otherwise increase power consumption.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4611277A1Optical line terminal with adjustable power consumption
Publication Date: 2025.09.03 NOKIA SOLUTIONS & NETWORKS OY
  • EP4611277A1 patent drawingFigure 1
  • EP4611277A1 patent drawingFigure 2
  • EP4611277A1 patent drawingFigure 3

AI summary

Example embodiments describe an optical line terminal (110), OLT, configured to communicate with optical network units (131, 132, 133), ONUs, by means of an optical distribution network (120), ODN, in a passive optical network (100), PON; wherein the OLT comprises one or more transmitter circuitries (111) configured to transmit a downstream optical signal (115) to the ONUs according to transmitter settings that determine a power consumption of the OLT; and wherein the OLT further comprises a controller (112) configured to adjust the power consumption of the OLT by adjusting one or more of the transmitter settings (145) while respecting minimal channel qualities of the downstream optical signal between the OLT and the respective ONUs.