An efficient synchronisation protocol for wireless sensor network

Time synchronisation is a critical topic in wireless sensor networks for its wide applications, such as data fusion, TDMA scheduling and cooperated sleeping, etc. In this paper, we present an Accurate Time Synchronisation (ATS) protocol based on linear least square for sensor networks. Unlike the previous protocols, all nodes are not synchronised to some reference nodes or sink node, but to a virtual clock. Moreover, each pair of the nodes is synchronised to each other. The main advantages of ATS are simplicity and accuracy. Especially, the variance of the synchronised drift error is less than Dsδ/2β2, where Ds, δ and β are the depth of the network, the maximal variance of the link delay and the sampling interval, respectively. The experiments show that ATS protocol has achieved at least 37% performance enhancement than the previous pairwise algorithm.