Time Division Flooding Synchronization Protocol for Sensor Networks

Clock synchronization is an essential service for various applications in wireless sensor networks (WSNs). Most of available synchronization protocols are based on CSMA MAC scheme. They are energy inefficient in dense sensor networks. Despite many power-saving TDMA MAC protocols have been proposed, few of them are qualified to flood synchronization messages. The novel one here adopts a carefully designed time division flooding scheme, which divides time into slots and assigns each node a unique one for transmitting synchronization packets. In this way, the active duration of each node can be dramatically reduced. The new slot allocation policy guarantees active periods of nodes along the forwarding paths be scheduled successively, so synchronization packets can be spread out in a short time. Besides, a special clock frequency skew compensation technique is employed to prolong the re-synchronization interval. Simulation shows that our protocol achieves high energy efficiency and fast convergence speed.