On meaningful parameters for routing in VANETs urban environments under realistic mobility patterns

A Vehicular Ad Hoc Network (VANET) is an instance of MANETs that establishes wireless connections between cars. In VANETs, routing protocols and other techniques must be adapted to vehicular-specific capabilities and requirements. As many previous works have shown, routing performance is greatly dependent to the availability and stability of wireless links, which makes it a crucial parameter that should not be neglected in order to obtain accurate performance measurements in VANETs. Although routing protocols have already been analyzed and compared in the past, simulations and comparisons have almost always been done considering random motions with non-urban specific parameters. But what would be the effects of urban motions on the simulation parameters, and what would be their consequences on routing performance ? In this paper, we illustrate how realistic motion patterns affect the velocity and how new parameters become necessary to evaluate the performance of routing protocols in VANETs. To express our point, we evaluate the performance of AODV with realistic urban scenarios. We show how new urban specific parameters have significant impacts on routing, and de-facto replace some non-urban specific parameters. For example, the average velocity appears to be irrelevant in urban scenarios and should be replaced by road segment lengths.