Simulation is a key tool in the development of wireless systems, protocols, and applications. This is especially true for large and mobile networks such as Vehicular Ad-hoc Networks (VANETs), as real-world experiments quickly become too expensive and complex with increasing numbers of nodes. However, accurate simulation of such wireless networks may take a long time to compute. This is mainly due to the sequential processing in event-based simulation cores like OMNeT++ or ns-3. This is especially troubling when debugging new protocols or when interfacing with Hardware in the Loop (HIL) or other real-time simulation. In this paper, we propose a new approach to accelerate simulation of wireless communication by utilizing asynchronous background computations. Expensive computations that can be isolated from the simulation kernel are started as early as possible and pushed to background threads. At the point in time when the result is needed, the computation may already be complete. This allows for parallelization without an explicit lookahead value. As a proof-of-concept, we implemented the concept in Veins, a state-of-the-art VANET simulator. By offloading wireless signal attenuation model computation to the background, we achieve speedups of up to 3.5, depending on the scenario.
