Time synchronization methods for wireless sensor networks: A survey

Wireless sensor networks consist of many nodes that collect real-world data, process them, and transmit the data by radio. Wireless sensor networks represent a new, rapidly developing direction in the field of organization of computer networks of free configuration. Sensor networks are used for monitoring a parameter field, where it is often required to fix time of an event with high accuracy. High accuracy of local clocks is also necessary for operation of network protocols (for energy-saving purposes, the nodes spend most of the time in the sleeping mode and communicate only occasionally). In the paper, base techniques used in the existing time synchronization schemes are analyzed; models of local clock behavior and models of interaction of the network devices are described; classification of the synchronization problems is presented; and a survey of the existing approaches to synchronization of time in sensor networks is given.