A distributed multi-hop low cost time synchronization algorithm in wireless sensor network developed for bridge diagnosis system

Due to the oceanic climate and frequent earthquakes in Japan, bridge health diagnosis is a problem of greater complexity. In bridge diagnosis system, we develop a wireless sensor network to sample and gather the vibration data of bridge. Time synchronization is a crucial component for the wireless sensor network (WSN), because large populations of sensor nodes will collaborate in order to complete the measuring data at the same time, data gathering, data fusion and localization. In the wireless sensor network with large scale of energy limited nodes, multi-hop time synchronization is necessarily applied. To solve above mentioned problem, some protocols such as RBS, TSPN FTPS etc. are proposed. However most of the algorithms mainly focus on the precision of synchronization. In fact energy efficiency is also a challenge in a resource-limited WSN. In this paper an improved time synchronization scheme is proposed with the purpose of reducing energy consumption and lengthening whole WSN' life. Performance analyses, simulations and realization in node hardware of WSN are also presented.