Context and Network Aware Communication Strategies for Connected Vehicle Safety Applications

Connected vehicle safety systems, such as cooperative collision warning (CCW) or avoidance (CCA) systems, rely on vehicle-to-vehicle communication for obtaining real-time situational awareness and detecting possible hazards. The majority of systems that use vehicular networks may benefit from separation of functionalities in communication and application layers. This separation streamlines design of many applications and provides Internet-style flexibility. However, for safety critical applications, the inherent loss of performance due to independent operation of communication and application layers may result in unacceptable degradation of reliability. We show that by considering the safety context and network performance in the communication subsystem design (thus weakening layer independence), significant gain in system reliability is possible. Context awareness is achieved by coupling communication behavior to "safety system performance"; for example using vehicle tracking accuracy to determine the required communication timing. Network awareness is achieved by using feedback from the network to influence the estimated safety system performance (tracking error), and consequently the communication controller. Safety performance metrics that can be used include hazard detection accuracy, or warning accuracy for CCW, or vehicle tracking accuracy. Simulation results, using data from field tests, show the effectiveness of context and network aware communication.