A New Energy-Efficient Time Synchronization Protocol in Wireless Sensor Networks

In some time critical Wireless Sensor Networks (WSN), time synchronization is crucial in the working process. Due to the limitations of WSN, such as the equipment dimension, the computing power, the data storage and energy capacity of the node, there are some special requirements for the time synchronization scheme, including synchronization accuracy, protocol overhead, and energy efficiency. During the past ten years, many researchers have investigated the time synchronization in WSN, and proposed numerous time synchronization protocols. However, most of the protocols are engaged in how to improve time synchronization accuracy, without regard to the energy consumption. PBS (Pair-wise Broadcast Synchronization), a low-power and fast synchronization protocol, utilizes very little message exchange to make all slave nodes synchronize within a single hop. In this paper, an energy efficient protocol is put forward on the basis of PBS, dubbed IPBS (Improved Pair-wise Broadcast Synchronization), which uses little extra message exchange to extend time synchronization of the slave nodes to two hops with high accuracy.