The impact of discrete clock on time synchronization in wireless sensor networks

As in many other distributed systems, time synchronization is an important service in wireless sensor networks. Most wireless sensor network applications are targetted at retrieving information from surrounding environments. In many situations, the temporal property of a physical event is critical to wireless sensor network applications. There are many time synchronization techniques for wireless sensor networks in literature. However, all of these techniques are based on continuous clock model, which cannot best describe the characteristics of system time in wireless sensor networks. In this paper, we propose a novel discrete clock model. This model is introduced by a formal definition and the impact of using discrete clock in time synchronization for wireless sensor networks is analyzed. A novel clock parameter estimation technique is also presented, which is based on the discrete clock model. Furthermore, the performance of the proposed technique is verified by simulation. According to our simulation, the proposed technique can achieve same synchronization precision with less message exchanges than existing protocols.