Behavior of clock-sampling mutual network synchronization in wireless sensor networks

Clock synchronization is an important component of wireless sensor networks both for co-ordination of node communications and for time stamping sensor data. The properties of the previously presented clock sampling mutual network synchronization algorithm (CS-MNS) are explored. The desirable properties of this algorithm include simplicity, low communication and processing overhead, and fully decentralized operation. Past simulation and analysis has shown clock convergence under specific conditions in single hop networks. We show that in the absence of offset errors the network clocks converge. In the presence of offset error we present conditions on the degree on clock asynchrony under which the network clock rates show convergent behavior. The analysis is applicable as long as the network topology is connected and thus is of interest in both single-hop and multi-hop environments. We show how the network designer can use these conditions to add a bias term to the CS-MNS algorithm and thus improve the start-up dynamics of the algorithm. Additionally, we discuss the algorithm from a security standpoint. Finally, we propose a method for adding external reference synchronization that is compatible with our security discussion.