A Fault-Tolerant Protocol to Enable Distributed State Machines Using IEEE802.11p

Autonomous vehicles promise a revolution in mobility, enabling safe, resource-efficient urban and inter-urban transport with a high degree of user convenience. To achieve optimal efficiency, autonomous vehicles must be viewed as a network of communicating cyber-physical systems which exchange information to optimize a utility function under strict security and safety requirements. Vehicles can exchange information to extend their perception horizon, exchange driving modes to enhance scene understanding and most importantly cooperate directly with other automated and autonomous vehicles in cooperative driving maneuvers such as platooning. In this paper we present a novel communication protocol built on the current vehicular communication standard IEEE 802.11p, which enables negotiation and execution of cooperative driving maneuvers based on distributed state machines. The main goal of this protocol is to achieve a common synchronized state and common state transitions while supporting fault-tolerance and self-supervision under security and safety constraints. This paper presents the Collaborative Maneuver Protocol (CMP) and provides a formal proof of correctness. We furthermore present an application in a platooning function and provide an evaluation of robustness in regard to packet loss.