Dynamic Continuous clock Synchronization for IEEE 802.15.4 based sensor networks

Clock Synchronization is an important service in wireless sensor networks (WSN) since it can be used for data integration, for the implementation of TDMA based approaches or for synchronous data acquisition. One main issue in WSN concerns the power consumption since the batteries have a limited capacity an often they cannot be replaced. In this paper we present a Dynamic Continuous clock Synchronization algorithm which provides a virtual common clock among a master and a group of slaves. The main feature of the approach proposed is the ability to allow nodes to sleep for long times and exchange only rare synchronization packets however providing a good quality common clock. The synchronization algorithm has been implemented inside embedded devices as a middleware over the MAC, without any modification to the original communication protocol.