An Energy Efficient Synchronization Protocol for Target Tracking in Wireless Sensor Array Networks.

Jie Shen,Ming Yin,Ji-An Luo,Zhen-Hui Li,Zhi-Bo Wang,Zhi Wang

doi:10.3390/s19061367

Abstract

Time synchronization is an important middleware function that supports the Quality of Service (QoS) of systems in wireless sensor array networks. Instead of providing high synchronization accuracy for all application scenarios, we argue that synchronization protocols should be application specific. In this paper, we exploit the synchronization requirements of target-tracking systems in wireless sensor array networks and propose an energy-efficient Sensor Array Synchronization Protocol (SASP), which provides the required synchronization accuracy to guarantee the QoS. Specifically, when no target appears, to guarantee system lifetime, coarse synchronization is achieved with little overhead by piggybacking time information onto periodical network maintenance packets. Once targets appear, SASP achieves high inter-array and relatively higher intra-array synchronization accuracy rather than the traditional network-wide high accuracy on average. In this way, it guarantees reliable communication and accurate data fusion, while reducing energy consumption. Theoretical analysis and extensive evaluations show the effectiveness of the proposed protocol.

Highlights

Wireless Sensor Networks (WSNs) [1] have been widely used in many applications, such as environmental monitoring [2,3], localization [4,5], data publishing with privacy [6,7], target tracking [8,9], and healthcare [10,11]
We focus on the synchronization protocol designed for a target-tracking system in wireless sensor array networks
We propose an energy-efficient synchronization protocol called the Sensor Array Synchronization Protocol (SASP) to satisfy the different synchronization requirements and reduce energy consumption

Summary

Introduction

Wireless Sensor Networks (WSNs) [1] have been widely used in many applications, such as environmental monitoring [2,3], localization [4,5], data publishing with privacy [6,7], target tracking [8,9], and healthcare [10,11]. WSNs are large-scale and decentralized with thousands of nodes [12]. Time synchronization, which builds a common understanding of time among all nodes, is one of the most important techniques in WSNs [13,14,15] and other wireless scenarios [16,17,18]. Due to the low quality of crystal oscillations, the limited computation capabilities, the uncertainty in wireless communication, and the limited power supply, time synchronization in WSNs is still a challenging problem. Many synchronization protocols for WSNs have been proposed. Most of them focus on achieving high synchronization accuracy, e.g., at tens of μs or even higher clock accuracy level

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Conclusion