A Simple Algorithm for Clock Synchronization in Wireless Sensor Networks

Abstract

Clock synchronization represents a crucial element in the operation of Wireless Sensor Networks (WSN). For any general time synchronization protocol involving a two way message exchange mechanism (e.g., Timing Synch Protocol for Sensor Networks (TPSN) [1]), the Maximum Likelihood Estimate (MLE) for clock offset under the exponential delay model was derived 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 achieving long term synchronization which in turn results in reduction of message exchanges and hence minimal power utilization. The MLE for clock offset as well as skew under the exponential delay model for TPSN were derived in [6]. In this paper; due to complexity reasons for finding the MLE, a simple and efficient algorithm is presented as an alternative to the ML estimation which particularly suits the low power demanding regime of wireless sensor networks.