Asynchronous Time Synchronization Protocol for WSNs

The simplicity of time synchronization is a necessary requirement for decentralized Wireless Sensor Networks (WSNs) to operate well in harsh environments. The averaging consensus control protocol (ACCP), that uses single hop communication, performs well in such environments. However, it works based on synchronous time synchronization mode which is unrealistic since the nodes in WSNs in real environment cannot exchange/update information at exactly same time. This paper proposes asynchronous realization/protocol for WSNs based on averaging consensus control. It works on a sequential manner and therefor called Timed Sequential Asynchronous Update (TSAU) protocol. The proposed protocol is tested by simulations and by experiments, and shown to achieve a small time synchronization error. Finally, TSAU is shown to be reliable since it maintains good time synchronization even when connectivity is not available all the time or when the network is under attack by a malicious node.