A quantitative analysis of improved DSRC system using repetition based broadcast safety messaging with hidden terminals

Broadcast communications are widely proposed for safety messaging. In the case of highway vehicular networks however, constantly broadcasting safety messages inevitably cause the well-known hidden terminal problem. Three existing repetition-based broadcasting protocols have shown to meet the reliability and delay requirements for DSRC safety systems. However, when compared with one another, all of these protocols have not been tested under hidden terminals scenario. In this paper, we propose a quantitative model to evaluate the quality of service (QoS) of DSRC systems using these three leading repetition-based protocols under hidden terminals and highway scenarios. The performance of our model is analyzed by means of probability of success and delay performances. Our performance study shows that the repetition-based protocols do not meet the DSRC critical safety reliability requirements when tested under higher transmission loads with hidden terminals taken into account. Under lower transmission loads, these protocols only meet the reliability requirements at relatively low vehicle densities. Our quantitative model and performance results presented in this study also serve as a benchmark for further improvement of DSRC systems´ performance.