Safety requirements for monitoring and communicating operational data for vehicles in Intelligent Transport System

Abstract: In the past few years, wireless technologies performances have been greatly improved to address various kinds of communications. However, in applications requiring the transmission of safety-critical data such as in industrial systems, wired solutions are still preferred to wireless networks. The challenge is then to develop safety-critical wireless applications in order to take advantage of the low cost and reduced installation complexity of wireless networks. In this Master Thesis, a remote-controlled road vehicle has been studied as an example of safety-critical wireless application. The purpose of the project has been to design and implement an embedded system and a user interface that enable the remote control of the vehicle. As the functional safety of a road vehicle is highly important, appropriate safety requirements need to be elicited and considered in the design of the wireless communication protocol. By following the ISO 26262 standard steps, safety requirements have been defined for the system. A communication protocol has then been established considering the safety requirements and the expected functionalities of the system. Finally, a prototype has been built for verification and validation purpose. The prototype consisted of a model car equipped with a microcontroller and an off-the-shelf (OTS) Wi-Fi module. A user interface running on any Android device has also been developed. The final achievements of the project were that the model car could be controlled in speed and direction by the user thanks to the interface. In addition, the model car could react automatically to some hazardous situations by reaching a safe state. The conclusion of this project is that the design of a communication protocol is highly dependent on the system expected performances and characteristics, including the functional safety. When these parameters lead to heterogeneous protocol requirements, concessions have to be made. When dealing with a safety-critical application, the functional safety of the system must be the priority. Finally, when off-the-shelf (OTS) hardware is used to implement the wireless communication, it must be chosen carefully as it constitutes the main limitation of the protocol performances.