Time Synchronization Method based on a Virtual Node for Wireless Sensor Networks

Time synchronization is a basic supporting technology in Wireless Sensor Networks (WSNs). Most recent synchronization methods apply MAC-layer time-stamping to avoid uncertainties of access time. However, MAC-layer time-stamping may not be available for many modem radio modules. In this paper a time synchronization method with non-dependence of MAC-layer sending time-stamping is proposed. In the method, a virtual node is employed by the time source node to assist in time synchronization process, so as to avoid using MAC-layer sending time-stamping. The performance of the method is evaluated and compared with other well-known protocols by experimental results. The method can be widely used for many wireless systems without restriction of MAC-layer time-stamping.