Hierarchical Time-frequency Synchronization Mechanism for Time Sensitive Networking

Modern Industrial Internet-of-Things (IIoT) requires reliable interaction and integration of data in the network. Thus, time sensitive networking (TSN) is a promising technology due to deterministic latency guarantee mechanisms for data transmission. However, the multiple mechanisms are based on the networkwide precise time synchronization. In this paper, to achieve precise and reliable clock synchronization of TSN, we propose a hierarchical timing-frequency synchronization mechanism. Specifically, the network is divided into two layers according to the network clock synchronization function. The top layer adopts tree-based synchronization to provide a global clock and an interface with external standard clock synchronization, and the underlying one adopts a distributed synchronization protocol to improve the reliability, which obtains the reference clock by multiple nodes to avoid the single point of failure. To improve synchronization efficiency, a time-frequency fusion synchronization mechanism is proposed, which comprehensively considers the synchronization time slot difference and the time-frequency coupling relationship to improve the synchronization speed under the same synchronization period. Simulation results show that the proposed synchronization mechanism has higher synchronization efficiency than the traditional methods, and improves the clock synchronization speed and accuracy significantly.