Abstract: Wireless Sensor Network（WSN） realizes human observing the real world, the nodes in the network can work separately, so such network needs clock synchronization to make sure the sequence of events. This paper expounds WSN clock synchronization’s related problems, explaining some synchronization methods by the way they use to propogate messages. Then the paper presents a quantitative and qualitative comparison of them, and raises the idea of algorithms fusion in the light of the new features of Wireless Sensor and Actor Network（WSAN）.

Key words: Wireless Sensor Networks（WSN）, Wireless Sensor and Actor Network（WSAN）, clock synchronization, fusion design

摘要： 无线传感器网络实现了人类对现实世界的观测，由于网络中节点可以单独监测，因此在这样的网络中节点间需要时间同步，以确定事件发生的顺序。阐述了WSN时间同步的相关问题，并从同步报文传递方式的角度详细介绍了几种时间同步算法；从定性和定量两个方面对算法进行了比较。在此基础上，针对WSAN的新特点提出算法融合的设计思想。

关键词: 无线传感器网络, 无线传感器反应网络, 时间同步, 融合设计