Extending Reference Broadcast Infrastructure Synchronization Protocol in IEEE 802.11 as Enabler for the IIoT

Realizing the industrial Internet of Things, more and more mobile use cases will emerge in the industrial landscape, requiring both novel concepts and smooth integration into legacy deployments. Since accurate time synchronization is particularly challenging for wireless devices, we propose a concept for simple but accurate synchronization in IEEE 802.11 wireless local area network that extends the Reference Broadcast Infrastructure Synchronization protocol, and a suitable integration of IEEE 802.1AS that is part of the IEEE time-sensitive networking standards. In addition, the concept is evaluated with a testbed using commercial off-theshelf hardware and a realistic discrete automation demonstrator equipped mostly with industrial components. By using the aforementioned devices for wireless communications, this concept can be directly applied in existing industrial solutions, thus achieving the proposed results. It is shown that the achieved synchronicity is suitable for a wide range of mandatory mobile use cases, which are most important for a fully functional industrial Internet of Things.