Clock Recovery in Mobile Meter Networks After Power Outage

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Solution Overview

Problem

Automated meter reading systems face challenges in maintaining accurate clock reference data during power outages, especially for battery-powered devices in mobile information collection networks, which can disrupt calendar and schedule-based events.

Innovation Solution

Deploying extended clock holdover nodes in mobile information collection networks and configuring battery-powered devices to periodically broadcast clock reference data, or waking them up to provide clock data to line-powered devices, ensures clock synchronization is maintained after power restoration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If battery-powered devices are used in mobile information collection networks, then device portability and flexibility are improved, but clock reference data accuracy deteriorates during power outages

Engineering Contradiction:

Improvedevice portabilityVSAvoidclock reference data accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces line-powered devices as intermediary clock reference sources that battery-powered devices can query when they lose their clock reference during power outages. These line-powered devices maintain accurate clocks continuously and serve as mediators to restore time synchronization without requiring external intervention or compromising device portability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If extended clock holdover nodes are deployed, then clock reference data availability is improved during power outages, but network device complexity increases

Engineering Contradiction:

Improveclock reference data availabilityVSAvoidnetwork device complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-service mechanism where battery-powered devices autonomously detect clock loss and independently query line-powered devices for time reference data. This eliminates the need for complex centralized clock management systems or extended holdover capabilities in every node, as each device handles its own time synchronization needs through simple query-response interactions.

Inventive Principle:

Principle #25Self-service

3Speed

If battery-powered devices continuously broadcast clock reference data, then clock synchronization speed is improved, but energy consumption increases

Engineering Contradiction:

Improveclock synchronization speedVSAvoidenergy consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic broadcasting where battery-powered devices transmit their clock reference data at predetermined intervals rather than continuously. This reduces energy consumption significantly while maintaining adequate clock synchronization speed for network operations, balancing the trade-off between synchronization responsiveness and power conservation.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS9078050B2Techniques for clock recovery in a mobile information collection network following a power outage

Publication Date: 2015.07.07 ELSTER SOLUTIONS LLC

AI summary

Clock reference data may be recovered or updated in networks that include line-powered devices and other devices susceptible to power outages. For example, for a mobile information collection network, one or more devices with extended clock holdover may be strategically deployed throughout the mobile information collection network to provide reference clock data. As another example, battery-powered devices may be woken up in order to provide clock reference data to other devices. Alternatively or additionally, the battery-powered devices may be configured to periodically broadcast their clock reference data to other devices.