Rapid-Flooding Time Synchronization for Large-Scale Wireless Sensor Networks

TL;DR

This paper introduces the RMTS protocol, a rapid flooding time synchronization method for large-scale wireless sensor networks that reduces delay errors and achieves fast, accurate synchronization over many hops.

Contribution

The paper presents a novel RMTS protocol that employs maximum likelihood estimations to minimize by-hop error accumulation and improve synchronization speed and accuracy.

Findings

Achieves accurate synchronization within three periods over 24-hop networks

Reduces by-hop error accumulation as network diameter increases

Demonstrates faster convergence and higher accuracy in experiments

Abstract

Accurate and fast-convergent time synchronization is very important for wireless sensor networks. The flooding time synchronization converges fast, but its transmission delay and by-hop error accumulation seriously reduce the synchronization accuracy. In this article, a rapidflooding multiple one-way broadcast time-synchronization (RMTS) protocol for large-scale wireless sensor networks is proposed. To minimize the by-hop error accumulation, the RMTS uses maximum likelihood estimations for clock skew estimation and clock offset estimation, and quickly shares the estimations among the networks. As a result, the synchronization error resulting from delays is greatly reduced, while faster convergence and higher-accuracy synchronization is achieved. Extensive experimental results demonstrate that, even over 24-hops networks, the RMTS is able to build accurate synchronization at the third synchronization period, and moreover, the by-hop error accumulation is slower when the network diameter increases.