On reliability requirement for BSM broadcast for safety applications in DSRC system

In this paper, we derive application-level reliability metrics of various safety applications with worst-case settings and vehicular environments based on an accurate analytical model in one dimension vehicular communication networks. The reliability related QoS metrics in both the MAC-level and the Application-level including packet reception ratio, T-window reliability, and awareness probability are derived. Inspired by the correlation between road traffic and vehicle speed revealed by Greenshields model, we observe that the current reliability related QoS requirements for safety applications are set without considering change of road traffic. Based on the observation, a new reliability requirement setting is proposed to tune tolerance time for various safety applications with different road traffic. The QoS requirements for the three typical safety applications that are believed to have the most stringent QoS requirements are specified and discussed. Taking velocity, density and time into account, application-level reliability metrics are improved for high vehicle density. From the results obtained under worst case with different vehicle density, we can observe the feasibility of our proposed reliability requirement setting.