Wireless Sensor Networks: A Scalable Time Synchronization

This paper presents a novel Chained-RIpple Time Synchronization (CRIT) protocol that is scalable, flexible, and high-precise in Wireless Sensor Networks (WSN). CRIT adopts hierarchical and multi-hop time synchronization architecture with contributing energy-saving effects in WSN. The algorithm works in two phases. In the first phase, a horizontal structure between Missionary Nodes (MN) is established in the network by Piggy-Back Neighbor Time Synchronization (PBNT) algorithm. In the second phase, a vertical structure between a MN and Sensor Nodes (SN) is set up in each sensor group (SG) by Distributed Depth First Search (DDFS) algorithm. By applying these two phases repeatedly, all nodes in WSN efficiently synchronize to each other. For the purpose of performance evaluation, we first study the error sources of CRIT. In addition, we simulate CRIT in terms of synchronization errors of two phases using network simulator.