Energy-Efficient Time Synchronization Based on Asynchronous Source Clock Frequency Recovery and Reverse Two-Way Message Exchanges in Wireless Sensor Networks

TL;DR

This paper proposes an energy-efficient time synchronization method for wireless sensor networks that minimizes sensor node message transmissions by using asynchronous clock recovery and reverse message exchanges, improving accuracy and reducing energy use.

Contribution

It introduces a novel synchronization scheme tailored for battery-powered sensor nodes, combining asynchronous clock frequency recovery with reverse message exchanges, and provides performance analysis and simulation validation.

Findings

Outperforms conventional schemes in measurement time accuracy

Reduces message transmissions at sensor nodes

Enhances energy efficiency in sensor networks

Abstract

We consider energy-efficient time synchronization in a wireless sensor network where a head node (i.e., a gateway between wired and wireless networks and a center of data fusion) is equipped with a powerful processor and supplied power from outlet, and sensor nodes (i.e., nodes measuring data and connected only through wireless channels) are limited in processing and battery-powered. It is this asymmetry that our study focuses on; unlike most existing schemes to save the power of all network nodes, we concentrate on battery-powered sensor nodes in minimizing energy consumption for time synchronization. We present a time synchronization scheme based on asynchronous source clock frequency recovery and reverse two-way message exchanges combined with measurement data report messages, where we minimize the number of message transmissions from sensor nodes, and carry out the performance analysis of the estimation of both measurement time and clock frequency with lower bounds for the latter. Simulation results verify that the proposed scheme outperforms the schemes based on conventional two-way message exchanges with and without clock frequency recovery in terms of the accuracy of measurement time estimation and the number of message transmissions and receptions at sensor nodes as an indirect measure of energy efficiency.