Global time service in wireless sensor networks

Time information and time synchronization are fundamental building blocks in wireless sensor networks since many sensor network applications need time information for object tracking, consistent state updates, duplicate detection and temporal order delivery. Various time synchronization protocols have been proposed for sensor networks because of the characteristics of sensor networks which have limited computing power and resources. However, none of these protocols have been designed with time representation scheme in mind. Global time format such as UTC TOD (universal time coordinated, time of day) is very useful in sensor network applications. In this paper we propose time keeping and synchronization method for global time service in wireless sensor networks. We implemented and evaluated the proposed scheme in real test platform of MicaZ and TinyOS-2.0.