A flexible linear control algorithm for wireless sensor network synchronization

Time synchronization of wireless sensor network (WSN) nodes is essential to schedule orderly communication and monitoring tasks. In this paper, a synchronization algorithm based on linear control theory is used to compensate at run-time both time offsets and clock frequency skews. The proposed approach is innovative for two reasons. First of all, the controller correcting the local timers is able to work also in nonideal conditions (e.g., including random communication latencies and numerical quantization noise). Secondly, the computational burden of the algorithm and the amount of network traffic to transfer timing data are compatible with the requirements of typical low-cost WSN nodes. In fact, the time intervals between subsequent synchronizations tend to grows while the uncertainty decreases. As a consequence, each node is increasingly free to run other tasks. The correct operation of the proposed algorithm has been proved in a simulation framework modeling with great accuracy the behavior of a cluster of nodes.