Analysisandperformanceevaluationofatimesychronizationprotoco Lforwirelesssensornetworks

Analysis and Performance Evaluation of a Time Synchronization Protocol for Wireless Sensor Networks

Suyoung Yoon and Mihail L. Sichitiu Department of Electrical and Computer Engineering North Carolina State University Raleigh, NC 27695-7911 {syoon2,mlsichit}@ncsu.edu

Abstract— Time synchronization is a fundamental middleware service for any distributed system. Wireless sensor networks introduce new requirements to this age-old problem regarding its scalability, cost and precision. In this paper we analyze theoretically and evaluate the performance of a very simple time synchronization algorithm. The performance of the algorithm is deterministic and predictable. To evaluate its performance we implemented the algorithm on Mica2 Berkeley motes. The results show that the algorithm achieves very good precision with fewer resources than existing algorithms.

In this paper we focus on pair-wise time synchronization, i.e., synchronizing just two wireless sensor nodes within wireless range of each other. It was shown [6], [7] that the entire network can be globally synchronized using pairwise synchronization by forming a synchronization tree. In WSNs, such trees are normally formed for routing the data to and from the base stations. If for some reasons base stations are unavailable, a leader election algorithm can be employed [7]. In our previous work [6] we introduced tiny-sync (a brief overview is presented in Section III), a simple time-synchronization algorithm and compared its performance with an optimal time-synchronization algorithm. The comparison showed that tiny-sync performs very close to optimal (within 0.1%) at significantly less computational and storage costs. In this paper we analyze tiny-sync and evaluate its performance with a realistic testbed. II. R ELATED W ORK Time synchronization is a key service for many applications and operating systems in distributed computing environments. Many protocols have been proposed and used for time synchronization in...