Realization of Time Synchronization Protocol Based on Frequency Skew Bid and Dynamic Topology Using Embedded Linux System

The time synchronization of network will encounter a severe challenge due to the proliferation of scale in wireless sensor networks. In order to improve the precision of time synchronization in network, a time synchronization protocol based on frequency skew bid and dynamic topology (FBDT) is designed in the paper as well as realized on Embedded Linux System. To be able to effectively inhibit synchronization error accumulation in multi-hop, a clustering mechanism in network region is adopted to reduce synchronization hops. In the protocol, every node selects the parent node which has a more stable clock frequency and fewer synchronization hops to restrain accumulation of synchronization error, meanwhile, combining fast and slow synchronization strategy is utilized to meet requirement on two performance indicators of synchronization accuracy and convergence time. Availing itself of hops information to select the parent node dynamically, the protocol can fit well in the network of dynamic topology, with good resistance to destructive and scalability. A method similar with TPSN protocol is used to eliminate transmission delay during synchronization between two nodes. Testing results on embedded Linux development board indicate that the FBDT synchronization protocol can reach the precision of μs, which can satisfy the requirements for practical applications.