Improved Time Synchronization Algorithms Based on TPSN

Abstract

When number of levels increases, local clock offset difference also increases for Timing-Sync Protocol for Sensor Networks (TPSN). To address the problem, an algorithm of Timing-Sync Protocol for Sensor Networks of Chain (C-TPSN) is proposed in this paper. It can provide synchronization among the cluster roots first then the cluster roots can synchronize asynchronously with their cluster members hierarchically by dividing the network into a number of clusters, which decreases the cumulative difference and improves the accuracy; Moreover, because the TPSN algorithm, a time deviation synchronization algorithm, needs to perform periodically time synchronization so that message overheads are large. An algorithm of Adaptive Interval Synchronization (Adap-I) is provided to optimize for message overheads on the premise of meeting the requirements of some precision. Finally, NS2 simulation platform is used to simulate and test the algorithms from the aspects of synchronization difference and message overheads. The results show that the C-TPSN algorithm can synchronize more effectively with higher precision, and the Adap-I can optimize for message overheads on the premise of meeting the synchronization accuracy.