DiStiNCT: Synchronizing Nodes With Imprecise Timers in Distributed Wireless Sensor Networks

An effective and robust time synchronization scheme is essential for many wireless sensor network (WSN) applications. Conventional synchronization methods assume the use of highly accurate crystal oscillators (10-100 ppm) for synchronization, only correcting for small errors. This paper suggests a novel method for time synchronization in a multihop, fully-distributed WSN using imprecise CMOS oscillators (up to 15 000 ppm). The DiStiNCT technique is power-efficient, computationally simple, and robust to packet loss and complex topologies. Effectiveness has been demonstrated in simulations of fully connected, grid, and unidirectional ring topologies. The method has been validated in hardware on a grid of nine sensor nodes, synchronizing to within a mean error of 6.6 ms after 40 iterations.