Vehicular ad hoc networks are a class of MANET which have been designed to allow vehicles to exchange different types of information ranging from security messages to entertainment content. Wireless connection between nodes implies that the communication is subject to link volatility. For mainly money/time saving and efficiency reasons, the simulation of VANET is traditionally done by means of a network simulator such as Opnet, Veins, ns-2 [NS 02] or ns-3 [NS 03]. However, the plain vanilla versions of these software packages do not accurately model the main physical effects of the wireless channel [AND 06]. The consequence of this is that VANET simulations are over-optimistic. In this chapter, we will first describe the main aspects of the wireless VANET channel and underline its central role in VANET communications. Next, we will present the different modeling approaches we have followed to accurately simulate the VANET channel in ns-2 and ns-3. After showing the effect of realistic channel models on VANET simulation, we provide a solution, which is a trade-off between computing time and realism.
6.2. Influence of the channel propagation model on VANET simulation
In that which follows, we show the effect of realistic channel propagation models on Vehicular Ad-hoc Networks (VANETs) simulation. As we will see, independently from the simulator used, the more simplistic the channel propagation model used by the ...