Conceptual Design and Implementation of a Semantic IoT-Edge-Gateway Using the WoT Standard
Martin Biskup, Fabian Kohlmorgen, Markus Kuller · 2023
In recent years, there has been a steady increase in the number of connected IoT devices. These devices generate significant amounts of data, which can be highly heterogeneous in terms of data structures, protocols, and standards. In addition, purely cloud-based system solutions cannot operate autonomously - for example, in the event of a network failure. It is at this point, that the use of a local edge gateway offers several advantages. First, such a gateway can pre-process the data, thus reducing the data volume and saving bandwidth. Furthermore, by unifying data structures and providing semantic descriptions of device properties, a gateway can create a high degree of interoperability. If the Internet connection to the cloud systems is not available, the gateway fulfills the basic tasks autonomously. This paper presents a semantic edge gateway developed based on the Eclipse Kura project. Kura supports machine-to-machine communication in the industrial IoT (IIoT) domain, but due to its modularity and versatility, it can also be used in the general IoT environment. This paper describes a concept and a prototypical implementation that extends Kura with components and functions for semantic device and function description, thereby optimizing the information value and machine processing of this information for downstream applications. In this context, the W3C's Web of Things standard and the Thing Descriptions are used as a data model. The Thing Descriptions provide a standardized device and interface description, providing a basis for cross-system interoperability of different devices and systems.