Cluster-based hierarchical time synchronization for multi-hop wireless sensor network

Abstract

Advances in recent technologies such as MEMS, low power and low cost wireless communications, micro sensors and embedded systems, realize the feasibility of WSN research increasingly. In the era of ubiquitous computing, the need for WSN is significantly rising. WSN has attractive potentials due to strong usability and feasibility to the various fields. A WSN is typically made up numerous sensors which do collaborative works over the network. Thus each node in such network needs common norms to explain and express the own information. As a norm, time information is one of the most necessary infrastructures to any collaborative system. To couple the network with real physical world tightly, we provide a network-wide time synchronization introducing the abstractions of cluster and hierarchy. In this paper, we propose the $\It{cluster-based hierarchical time synchronization}$(CHTS) protocol for WSNs. Generally the error of time synchronization has the tendency of being accumulated while the hop count along the synchronization path increases in multi-hop wireless sensor network. Thus we cluster the randomly deployed nodes to decrease the hop count from the reference clock node to each node. Then we apply different optimal synchronization mechanisms to the cluster heads and cluster members for the sakes of the power efficiency with using the broadcast manner explicitly. We proved the performance enhancements with simulation comparisons.