Time synchronization for ZigBee networks

Time synchronization is essential for most network applications. It is particularly important in a wireless sensor network (WSN) as a means to correlate diverse measurements from a set of distributed sensor elements and synchronize clocks for shared channel communication protocols. Wireless sensors are typically designed with very stringent constraints for size, cost, and especially power consumption. The flooding time synchronization protocol (FTSP) was developed explicitly for time synchronization of mesh-connected wireless sensor networks. However, ZigBee can also accommodate master-slave networks that can be more power-efficient. We optimized the FTSP for master-slave WSNs and implemented it using TinyOS 1.1.8 and ZigBee-compliant hardware. Our approach allows better synchronization and reduced power consumption of wireless nodes. In this paper we present implementation and experimental results.