Autonomous systems perform complex tasks to analyse and to react on their environment. One way to handle this complexity is distributing the functionality to several hardware modules. Even in small autonomous systems the predictability of the communication and the synchronization of all modules is vitally important. This book provides a survey of five protocols that play a major role in the automotive industry and in the domain of real-time communication: CAN, LIN, Flexray, TTP/C, and TTP/A. The protocols are compared and analysed regarding their suitability for small autonomous systems. Following the results of this investigation, TTP/A is ported to the hardware of the Tinyphoon robot, a research platform for small autonomous and distributed systems. On the basis of the outcome of this case study enhancements and adoptions of TTP/A are proposed. To address the diversity of hardware a general concept of making TTP/A more portable is elaborated.