关键词: 无线传感器网络, 时间同步, 双向消息交换, 分布式一致时钟同步

Abstract: Time synchronization is one of the most important protocols in Wireless Sensor Networks（WSN）, and it is the key mechanism to ensure the cooperative work of each node in the WSN. According to the reference node, time synchronization algorithm is divided into two-way message exchange time synchronization algorithm and the distributed consensus time synchronization algorithm, the two-way message synchronization algorithm is divided into the two-way message exchange algorithm based on sender-receiver synchronization, pairwise broadcast message exchange algorithm and time synchronization algorithm based on ACK frames according to the decrease of the energy loss. The time synchronization message sending number of these three kinds of two-way message time synchronization algorithm is gradually decreasing, so energy consumption is also reduced. However, distributed consensus time synchronization algorithm abandons the selection of reference nodes, and simultaneously synchronizes all the sensor nodes, which avoids the failure of reference nodes and other nodes cannot be synchronized. Based on the analysis of the existing research, this paper concludes the possible future research directions of the time synchronization algorithm.

Key words: Wireless Sensor Network（WSN）, time synchronization, two-way message exchange, distributed consensus clock synchronization