An Approach for Precise, Scalable, and Platform Independent Clock Synchronization

Clock synchronization is an important issue in wired and wireless networks as a common time basis is essential for coordinated activities of nodes in distributed systems. Typical applications demanding precise synchronization are Industrial Internet scenarios having real-time constraints, Wireless Sensor Networks (WSNs) where the nodes communicate only for a short period and can sleep the remaining time to save energy, approaches based on Time Division Multiple Access (TDMA), and distributed measurements. The basic idea of our approach is to estimate all delays in a network. As a result, we can estimate the one-way delay between a reference node and all other nodes in the network. Consequently, we can use broadcast messages to synchronize the entire network. Utilizing a novel measurement method and a Java prototype implementation, we show that our approach achieves a high precision (approximate to 123 mu s). Furthermore, it is highly scalable and platform independent. As our synchronization approach operates at the application layer, it is suitable for both wired and wireless networks.