Opportunistic Clock Synchronization in a Beacon Enabled Wireless Sensor Network
Nicola Altan and Erwin P. Rathgeb
Wireless sensor networks (WSN) consisting of a large number of tiny inexpensive sensor nodes are a viable solution for many problems in the field of building automation. In order to meet the energy constraints, the nodes have to operate according to an extremely low duty cycle schedule. In such a scenario the reduction of the synchronization error, at least among directly communicating nodes, is a crucial functionality of the MAC layer. We propose a time synchronization mechanism based on the usage of a Kalman Filter (KF) on a smoothed sequence of measured beacon intervals. A side effect of this method is the introduction of a global clock synchronization. The implementation of the proposed solution is feasible on sensor devices with minimum processor, memory and energy capacity.
Keywords: Low duty-cycle, tine synchronization, Kalman Filter.