On the Benefits of Cooperation for Dependable Wireless Communications

The Industrial Internet-of-Things (IIoT) improves flexibility, productivity, and costs by interconnecting sensors, actuators, and controllers. Such interconnections increasingly rely on wireless communications, reducing deployment and maintenance costs while supporting mobility. The industrial domain, however, is mainly characterized by critical Machine-to-Machine communication. Therefore, state-of-the-art wireless communication protocols, such as WLAN and Bluetooth, are not suited for the IIoT. Consequently, we need high reliability and low latency to achieve dependable wireless communication.
A promising approach for Ultra-Reliable Low-Latency Communication (URLLC) is cooperative diversity, since the stations already collaborate toward a common goal, i.e., keeping the industrial process running. There, a sender exploits multiple independent transmission paths via cooperating relays to convey a packet to its destination. In contrast to spatial diversity, this approach also works with SISO transceivers. However, it is challenging that all stations have to share scarce transmission resources.
In this dissertation, we investigate mechanisms enabling dependable wireless communication, i.e., increasing reliability within a bounded low latency, where we focus on the benefits of cooperative diversity. Therefore, we explore different design options for URLLC and evaluate them, leveraging different methodologies. This dissertation thus offers valuable insights into designing communication protocols with challenging requirements. At the example of cooperation, we thoroughly retrace the development process from analysis to prototypical deployment. The achieved results contribute to URLLC, and they provide a critical examination of the selected evaluation methodologies.