Using Software-Defined Radio to Validate Wireless Models in Simulation

Simulation is an efficient and powerful tool for studying wireless networking. The lack of physical layer (PHY) accuracy in many popular network simulators such as ns-2 and OPNET has been observed to produce misleading results. In this paper, we demonstrate a technique for validating the packet-level PHY models in network simulators against the physical layer of a software-defined radio testbed. Specifically, we evaluate the accuracy of model-based simulations against hybrid (i.e., joint packet and waveform) simulations of the real PHY implementation directly executing in a simulation environment. We demonstrate that this direct-execution approach is an effective means of evaluating the accuracy of packet-level PHY models from the perspectives of different protocol layers using a broad set of operating conditions. Moreover, this is an effective means of establishing when a packet-level PHY model can be used to generate trustworthy simulation results.