Accelerating vehicle network simulations in urban scenarios through caching

When designing new Vehicular Network (VN) protocols, the cost and time required for deploying real prototypes to run tests and evaluate new proposals becomes excessive. Consequently, simulation plays a key role in Vehicular Networks development. Simulation models and tools have been improved to better mimic the different factors that affect communications in real world scenarios. In terms of the communications channel, models have evolved from simplistic distance-based models to elaborated stochastic models that take into account both distance and the obstacle layout. However, increasing the complexity of the models also increases the time needed to run simulations. In this paper, we present an optimization applicable to the obstacle model included in VEINS, a well-known VN simulator, which relays on a cache table to accelerate ray-tracing calculations at the physical layer. Our results show that the proposed optimization can reduce by up to 75% the simulation time with minimal differences in terms of simulation results.