Date Added: Feb 2011
Accuracy is one of the most important performance metrics in clock synchronization. While state-of-the-art synchronization protocols achieve ?sec-order average accuracy, they usually do not focus on the worst case accuracy and do not have any deterministic guarantees. This lack of accuracy guarantee makes it hard for sensor networks to be incorporated into larger systems that require more reliability than, e.g., typical environmental monitoring applications do. In this paper, the authors present a clock synchronization algorithm with deterministic accuracy guarantee. A key observation is that the variability of oscillation frequency is much smaller in a single crystal than between different crystals. The algorithm leverages this to achieve much tighter accuracy guarantee compared to the interval-based synchronization methods mostly proposed in the literature of distributed systems.