The effect of 802.11a on DSRC for ETC communication

There are increasing interest recently in using 802.11p for ETC (Electronic Toll Collection) communication. However, there are two potential problems for using 802.11p for mission-critical applications like ETC. First, a 802.11p wireless network is prone to fading, shadowing, and interferences, which might result in packet losses. But the WSMP protocol in 802.11p standard does not provide any reliability mechanism. Second, since the frequency bands used by 802.11a and 802.11p are relatively close, it is possible that any 802.11a-based devices could potentially interfere the 802.11p traffic and disrupt the service. We previously proposed a simple session-layer protocol to improve the reliability of WSMP for ETC communication. In this work, we focus on investigating the effect of on-board 802.11a devices on ETC communication. We first demonstrate the possibility of that 802.11a could potentially interfere 802.11p traffic through theory and real-world experiments. Then, with extensive simulations, we discuss how on-board 802.11a devices could degrade ETC services in different scenarios.