title: Enhanced precision time synchronization for wireless sensor networks.
abstract: Time synchronization in wireless sensor networks (WSNs) is a fundamental issue for the coordination of distributed entities and events. Nondeterministic latency, which may decrease the accuracy and precision of time synchronization can occur at any point in the network layers. Specially, random back-off by channel contention leads to a large uncertainty. In order to reduce the large nondeterministic uncertainty from channel contention, we propose an enhanced precision time synchronization protocol in this paper. The proposed method reduces the traffic needed for the synchronization procedure by selectively forwarding the packet. Furthermore, the time difference between sensor nodes increases as time advances because of the use of a clock source with a cheap crystal oscillator. In addition, we provide a means to maintain accurate time by adopting hardware-assisted time stamp and drift correction. Experiments are conducted to evaluate the performance of the proposed method, for which sensor nodes are designed and implemented. According to the evaluation results, the performance of the proposed method is better than that of a traditional time synchronization protocol.
authors.affiliation: Institute of Logistics Information Technology, Pusan National University, Geumjeong-gu, Busan 609-735, Korea. marine@pnu.edu
authors.forename: Hyuntae
authors.initials: H
authors.lastname: Cho
authors.forename: Jongdeok
authors.initials: J
authors.lastname: Kim
authors.forename: Yunju
authors.initials: Y
authors.lastname: Baek
mesh_terms: D000465:Algorithms; D003195:Computer Communication Networks; D003201:Computers; D015233:Models, Statistical; D009991:Oscillometry / Q000379:methods; D010825:Physics / Q000379:methods*; D015203:Reproducibility of Results; D013686:Telemetry / Q000379:methods*; D013995:Time; D013997:Time Factors