Concepts for reliable and time-critical industrial communication based on IR-UWB systems

Industrial wireless communication demands high reliability and low latency. Since state of the art wireless sensor networks do not entirely meet the high requirements, new approaches have to be developed. In this regard, ultra-wideband systems are a promising system approach due to the robustness against frequency selective fading, its huge bandwidth and the operation at sparsely used frequency bands. In this thesis, optimizations of the physical layer (PHY) of an impulse-radio ultra-wideband (IR-UWB) system as well as novel concepts of a media access control (MAC) layer with the objective of meeting the requirements of industrial applications are presented and evaluated. In this regard, synchronization procedures for impulse-based ultra-wideband systems operating in frequency-selective fading channels are addressed, and solution possibilities are identified. The proposed synchronization procedures significantly increase the system performance. The next part of this thesis proposes an enhanced frequency hopping transceiver for industrial communication. The transceiver bases on a conventional single carrier system in combination with an adaptive frequency band selection and operates at the 5.8 GHz band. The performance of the system approach is investigated and compared with the IR-UWB system. The proposal outperforms the UWB system regarding the reliability and the coverage range. In the third key subject of the thesis, a low-latency MAC protocol is presented and evaluated based on the IEEE 802.15.4 IR-UWB PHY and a realistic scenario. Specific characteristics of industrial applications are seized and considered in the MAC approach. It is shown that this MAC approach enables not only a much lower latency, but also a higher scalability than conventional protocols.