VANET: Is 95% probability of packet reception safe?

In Vehicular Ad Hoc Networks vehicles periodically send beacon messages in order to gain mutual awareness of each others' presence. Successful reception of such beacons depends on various network conditions, e.g., transmission rate and power, as well as radio fading. Vehicular applications rely on such mutual awareness to supply the driver with safety and efficiency notifications. The Probability of Packet Reception (PPR) is the most common metric that is used to describe network performance, nevertheless, it is reflecting neither the acquired awareness nor application performance. Awareness, resides between network and application layers and can enable application layer to understand the network metrics and thus facilitate an evaluation of application performance. In this paper, we provide a methodology framework to evaluate application performance utilizing awareness. For this we first analyze the relationship between PPR and awareness and investigate feasible regions of network parameters and corresponding awareness ranges. Then we perform an evaluation of various awareness ranges on traffic safety metrics for the specific safety use case of a Stationary Vehicle Warning. We consider realistic driver behavior parameters and evaluate when awareness implies safety. As a second use case, Lane Change Warning application example is used to identify the required communication parameters that have to be met for a proper application performance.