Analysis of Cooperative Awareness Message rates in VANETs

To support applications for environment perception in Vehicular Ad-Hoc Networks (VANETs), vehicles send Cooperative Awareness Messages (CAMs) via wireless broadcast to inform other vehicles about their status. Each message received by a vehicle is processed by several application modules that run on hardware with limited resources whose capacity is not yet defined. Therefore, the received rate of CAMs is a crucial input for the development of series VANET products. In this paper, we quantify the received rate of CAMs and show that it can be high even for a low fraction of vehicles generating CAMs. We simulate road traffic in typical highway scenarios and estimate sent CAM rates. We introduce the notion of relative channel load and present a new approximative channel model to determine a vehicle's message reception probability. We use that model to simulate a vehicle's received CAM rates and propose a simple approximation formula.