Interaction between EDCA and HCCA: Simulation study of DSRC for work zone safety

Recently, academic researchers and car manufactures have directed major efforts to develop active safety systems for reducing car accidents. In particular, for work zones they proposed to use smart cones that send a warning radio message to vehicles when the smart cones detect the possibility of an accident. The dominant protocol for vehicular communication is Dedicated Short Range Communications (DSRC), where Enhanced Distributed Channel Access (EDCA) and Hybrid Coordination Function (HCF) Controlled Channel Access (HCCA) are the MAC protocol options. Even though two MAC protocols are specified in the standard, there has been no attempt to use two protocols cooperatively nor to study the performance of such hybrid system in an actual vehicular network. In this paper, we examine for the first time the performance of a system that exploits EDCA and HCCA concurrently in vehicular networks. In particular, we concentrate on interaction between two MAC protocols and how much the interaction affects system performance. In addition, we investigate whether the system is feasible for work zone safety applications, and suggest guidelines for improvements based on our simulation findings.