Fault-tolerant industrial wireless mesh network infrastructure

Modern industrial facilities have growing demands for wireless communication. Industrial applications need a communication service which can cope with mobility and environmental dynamics while maintaining realtime service quality. The goal of this thesis is to provide a reliable communication service with end-to-end guarantees on top of Wireless Mesh Networks. Applications should be able to specify their functional and non-functional end-to-end requirements, which the infrastructure then fulfi lls. This task is challenging due to the limited throughput capacity and highly dynamic nature of the wireless medium, which includes e° ects like varying transmission rates, changing links, mobility and even ocassional node failures. The approach taken in this thesis to master these issues is to apply the methods of fault-tolerance. The solution consists of a feedback control loop which adapts the network to the infl uence of dynamic e° ects by deploying resource assessment, resource admissi-on and resource provision. The control loop is combined with proactive measures which prevent service failures in the time between a fault occurs and is properly handled by the control loop. The developed mechanisms are implemented on top of the existing AWDS routing protocol. Crosslayerinterfaces to lower layers are used for obtaining more precise and timely information. The infrastructure provides an application interface for requesting QoS guarantees, and ensures their enforcement. The infrastructure is evaluated in an industrial application scenario, where a mobile robot is remote-controlled using live video and sensory feedback. This high-bandwidth real-time application is competing for medium access with background data streams. The evaluation shows that it is possible to control the robot without interruptions or service failures when all implemented components are active. At the sametime, the deactivation of any of the building blocks severely reduces the achievable service quality, showing their respective necessity. Therefore, the presented works uccessfully solves the challenge of providing a communication backbone for dynamic industrial environments. It therefore enables the introduction of high-bandwidth mobile applications like tele-robotics and augmented reality in industrial automation.