Intra-Network Clock Synchronization for Wireless Networks: From State of the Art Systems to an Improved Solution

Since the announcement of Industry 4.0 (I4.0), the concepts and ideas behind this revolution have been overturning. On the communication side however, all scenarios can be reduced to similar requirements. I4.0 communication requires real-time capability, reliability and interconnectivity of many clients. The realization of these requirements is already made possible by the IEEE standardized TSN technology. A key enabler for the realization of these requirements is a common time understanding of all involved instances, in order to coordinate the complexity arising in such a scenario. For this purpose, clock synchronization is an essential component of TSN. However, there is another essential feature that many I4.0 use cases have in common, which is the spatial dynamics of clients that only wireless communication can provide. This paper presents an approach based on WLAN, which is also able to meet these requirements. The essential points of clock synchronization as used in TSN are analyzed and transferred to WLAN and further concepts and optimizations will be introduced. These concepts are evaluated and analyzed in simulations. The result is a communication concept, which is able to exceed the performance of wired TSN as shown by various KPIs.