期刊名称：International Journal of Distributed Sensor Networks
印刷版ISSN：1550-1329
电子版ISSN：1550-1477
出版年度：2018
卷号：14
期号：9
页码：1
DOI：10.1177/1550147718797824
出版社：Hindawi Publishing Corporation
摘要：In view of the requirement on time synchronization for a kind of typical wireless sensor networks with long-chain-type topologies, taking into account the three-dimensional network model currently used by the localization algorithms, one feasible time synchronization algorithm is proposed in this article. Under the three-dimensional topology, nodes in the wireless sensor networks are divided into three kinds: the sensing nodes, the relay nodes, and the measured nodes. By analyzing the distribution characteristics of these three kinds of nodes, with the introduction of the pairwise broadcast synchronization and the series multi-hop synchronization protocol, the estimation of the clock offset and the clock skew of all the nodes in the wireless sensor networks are performed by virtue of the joint maximum likelihood and the least-squares method, thus the time synchronization of the wireless sensor networks with long-chain-type topology is solved. Moreover, the sink node evaluates the network periodically and adjusts the synchronizing cycle based on the difference between the network synchronization error and the given synchronization accuracy. The feasibility and effectiveness of this scheme are analyzed by simulations from the synchronization accuracy, the number of synchronization message, and the synchronizing cycle points of view.
关键词：Underground wireless sensor networks; time synchronization; long chain type; energy efficiency; joint maximum likelihood
