Low Power Endpoint Synchronization via Guaranteed Time Slots

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Solution Overview

Problem

In time synchronized channel hopping networks, low power endpoints face frequent communication requirements that shorten their battery life due to the need for continuous synchronization, impacting network stability and power management.

Innovation Solution

A low power endpoint is associated with a parent node, which assigns a guaranteed time slot and optional channel offset, allowing the LPE to enter a low power mode until wake-up, minimizing power usage by synchronizing and communicating only during designated time slots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an LPE engages in frequent communications to remain synchronized with the network, then network synchronization is maintained, but battery life is reduced

Engineering Contradiction:

Improvenetwork synchronizationVSAvoidbattery life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The LPE enters low power mode for predetermined intervals and wakes up at specific times to communicate with the parent node. This periodic communication pattern maintains network synchronization while significantly reducing power consumption compared to continuous communication, directly resolving the contradiction between maintaining synchronization and extending battery life.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The parent node acts as an intermediary that maintains the LPE's association and handles network synchronization on behalf of the LPE during its low power intervals. The parent node receives and forwards network messages, allowing the LPE to remain synchronized without actively communicating continuously, thus extending battery life while maintaining network reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If an LPE enters low power mode to extend battery life, then power consumption is reduced, but network synchronization may be lost

Engineering Contradiction:

Improvepower consumptionVSAvoidnetwork synchronization

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The LPE determines wake-up times in advance based on guaranteed time slot information received from the parent node. By pre-calculating when communication is needed, the LPE can enter low power mode confidently knowing it will wake up at the correct time to maintain synchronization, thus reducing power consumption without risking network synchronization.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The LPE receives feedback from the parent node regarding guaranteed time slots and channel offsets, which informs its wake-up schedule. This feedback mechanism ensures the LPE wakes up at appropriate times to maintain synchronization while spending maximum time in low power mode, balancing power consumption and synchronization reliability.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9974014B2System and method for maintaining synchronization with low power endpoints in a time synchronized channel hopping network

Publication Date: 2018.05.15 LANDIS GYR TECH INC

AI summary

Systems and methods are provided for maintaining a low power endpoint (LPE) synchronized on a time synchronized channel hopping network (TSCH). An LPE receives a guaranteed time slot (GTS) from a parent node. The LPE determines a wake-up time that coincides with or is prior to the GTS. The LPE enters a low power mode to conserve power until the wake-up time occurs. At that time, the LPE enters a regular power mode and may communicate with the parent node.