On the Necessity of Accurate IEEE 802.11P Models for IVC Protocol Simulation

In the scientific community, Inter-Vehicle Communication (IVC) protocols are frequently evaluated using simulation techniques, often using variants of WiFi stacks instead of IEEE 802.11p, which constitutes the basis for the new DSRC/WAVE standard. We discuss the necessity of using accurate WAVE models based on an extensive set of simulation experiments using: an IEEE 802.11b model, an IEEE 802.11b model tweaked to work in the same frequency range and using similar timings like IEEE 802.11p, as well as a fully featured channel hopping WAVE model. Even though, intuitively, the use of the different protocols will lead to a different network behavior, to the best of our knowledge, there has been no qualitative and quantitative evaluation or comparison of both worlds. According to our results, we can conclude that the simple WiFi model may indeed be used, but only for extremely sparse scenarios - this is exactly what has been validated using field tests. In denser traffic scenarios there is a significant deviation of the protocol behavior between WiFi (and its adapted variant) compared to WAVE. Thus, especially in dense scenarios, the application behavior is strongly influenced if simulated with the wrong model - leading to unrealistic results.