| A number of time synchronization protocols for wireless sensor networks (WSNs) have been recently proposed aiming at maximizing the accuracy and minimizing the power efficiency. This paper proposes novel clock skew estimators
for the protocols based on two-way timing message
exchanges to achieve long term reliability of synchronization. The proposed estimators are far more power efficient than the conventional ones by significantly increasing the resynchronization
period. Moreover, this clock skew correction
mechanism can be applied to the conventional protocols without any additional overhead. In fact, the proposed estimators assume simple steps and low complexity, a feature which is strongly demanding for WSNs consisting of cheap
and small nodes. In recent years, there have been proposed a few efficient synchronization algorithms such as Timing Synch Protocol
for Sensor Networks (TPSN), Reference Broadcast Synchronization(RBS), Flooding Time Synch Protocol (FTSP). The two-way message exchange mechanism is commonly used in receiver-to-receiver synch protocols as TPSN, and has clear benefits in some applications, for instance, high
latency acoustic networks. However, thus far the proposed protocols using two-way message exchanges do not consider the effect of clock skew between the two nodes although it is
the main reason why clock offset keeps drifting away. This paper presents and derives novel clock skew estimators based on two-way message exchanges. The proposed estimators prolong the re-synchronization period significantly
by adjusting clock skew between two nodes, and
therefore far less power resources will be required in the synchronization procedures. Moreover, the proposed clock skew correction mechanism can be directly applied to the conventional protocols with simple steps and low complexity.
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| Erchin Serpedin received (with highest distinction) the Diploma of electrical engineering from the Polytechnic Institute of Bucharest, Bucharest, Romania, in 1991. He received the specialization degree in signal processing and transmission of information
from Ecole Superieure D'Electricite, Paris,
France, in 1992, the M.Sc. degree from Georgia Institute of Technology, Atlanta, GA, in 1992, and the Ph.D. degree in electrical engineering from the University of Virginia, Charlottesville, VA, in January 1999.
He is currently an Associate Professor with Texas A&M University in College Station. His research interests lie in the areas of statistical signal processing and wireless
communications. Dr. Serpedin has received the NSF Career Award in 2001, NRC Fellow Award in 2005, ASEE Fellow Award in 2006, the CCCT 2005 Best Conference Paper Award, TEES
Fellow Award, and Outstanding Faculty Award in 2004. He is currently serving as Associate Editor for five major journals in the field of Telecommunications and Signal Processing: the IEEE Transactions on Wireless Communications, the IEEE Transactions on Signal Processing, the IEEE Communications Letters, IEEE Transactions on Communications and EURASIP Journal on Applied Signal Processing. He is also serving as a technical chair of the Globecom 2006 Conference.
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