Rüdiger Halfmann’s scientific contributions

The increasing demand for highly customized products, as well as flexible production lines, can be seen as trigger for the "fourth industrial revolution", referred to as "Industrie 4.0". Current systems usually rely on wire-line technologies to connect sensors and actuators. To enable a higher flexibility such as moving robots or drones, these connections need to be replaced by wireless technologies in the future. Furthermore, this facilitates the renewal of brownfield deployments to address Industrie 4.0 requirements. This paper proposes representative use cases, which have been examined in the German Tactile Internet 4.0 (TACNET 4.0) research project. In order to analyze these use cases, this paper identifies the main challenges and requirements of communication networks in Industrie 4.0 and discusses the applicability of 5th generation wireless communication systems (5G).

Flexible production processes and applications for Industry 4.0 expect a seamless, deterministic communication over scalable infrastructure networks that rely on a combination of wired and wireless technologies. Time-Sensitive Networking (TSN) and 5G are considered key technologies to meet the communication requirements of Industry 4.0. To integrate 5G into TSN, the 3rd Generation Partnership Project (3GPP) specified the 5G system (5GS) as Ethernet bridge, to exchange time synchronization and Quality of Service (QoS) requirement information between wired TSN entities and 5GS. QoS mapping between TSN and 5G is non trivial and requires a deeper analysis of relevant parameters and QoS processing. In this paper, different solution approaches for QoS mapping between TSN and 5G are presented and discussed. The contribution covers fundamentals and prerequisites on the way to a 5G QoS model for TSN, which has not yet been addressed in 3GPP nor IEEE.

5G and 6G wireless communications allow for novel and disruptive applications. While 5G was strongly focused on improvements on QoS and QoS guarantees that are necessary for industrial deployments, 6G will have a disruptive impact on possible use cases. Here, nearly each use case requires time synchronization of the involved systems. While PTP in its variations, e.g. IEEE 1588 v2.1 or IEEE 802.1AS, has established as standard for wireline systems, time synchronization of wireless or hybrid systems is still subject to research. Thus, the so-called RBIS protocol, which was originally developed and investigated for Wi-Fi, is mapped to 5G. This is possible, because both systems are infrastructure based and a suitable broadcast that fits to the requirements of RBIS protocol can be found in the control layer of 5G NR. Even if the 1 microsecond requirement that is required by some applications is not yet cracked, the accuracy of 1.3 microseconds and precision of <4.3 microseconds for non-invasive extension of existing 5G deployments is highly promising.

Industry 4.0 brings up new types of use cases, whereby mobile use cases play a significant role. These use cases have stringent requirements on both automation and communication systems that cannot be achieved with recent shop floor technologies. Therefore, novel technologies such as IEEE time-sensitive networking (TSN) and Open Platform Communications Unified Architecture (OPC UA) are being introduced. In addition, for the realization of mobile use cases, wireline technologies cannot be used and have to be replaced by wireless connections, which have to meet the high demands of the industrial landscape. Here, 5th generation wireless communication system (5G) is seen as a promising candidate. Especially encouraging and similarly challenging is the cooperative work of mobile robots, where particularly high demands on time synchronization arise. Therefore, this paper introduces a concept for the integration of TSN time synchronization (IEEE 802.1AS) conform with 5G to fulfill the requirements of these use cases. Furthermore, the paper describes a testbed for discrete manufacturing, consisting pre-dominantly of industrial equipment, in order to evaluate the presented approach.