Delay compensation method for time synchronization in wireless sensor networks

Time synchronization represent the most critical piece of infrastructure in any distributed system, especially for Wireless Sensor Networks (WSNs) which make particularly extensive use of synchronized time. Many applications of WSN need local clocks of individual sensor nodes to be synchronized. Almost any form of sensor data fusion or coordinated actuation requires synchronized physical time for reasoning about events in the physical world. However, while the clock accuracy and precision requirements are often stricter in WSN than in traditional distributed systems, energy and channel constraints limit the resources available to meet these goals. In this paper, one-way message dissemination time synchronization protocol is described. The main idea consists of bypassing the impact of nondeterministic time delay during creating and updating a local timestamp. Thanks to lower data dispersion, the estimated time line is much closer to the accurate time line. The synchronization error depends on CPU clock frequency and varies from 0.75 μs up to 24μs.