ESTIMATION OF CLOCK PARAMETERS FOR SYNCHRONIZATION IN WIRELESS SENSOR NETWORKS

Clock synchronization among the nodes is one of the most crucial factors in the performance of Wireless Sensor Networks (WSNs). The Maximum Likelihood Estimate (MLE) for clock offset under the exponential delay model for any time synchronization protocol relying on two-way timing message exchange between two nodes (e.g., Timing Synch Protocol for Sensor Networks (TPSN) [1]) was proposed in [2] assuming no clock skew between the nodes. Since all practical clocks are running at different rates with respect to each other, the skew correction becomes important for long term synchronization which in turn results in minimal power utilization. In this paper, the MLE for clock offset as well as skew under the exponential delay model for a two-way timing message exchange model are derived.