Date Added: Mar 2012
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.