A reactive channel model for expediting wireless network simulation

A major problem with leveraging event-driven, packet-level simulation environments, such as ns2[6], J-Sim[1], OpNet[2]), and QualNet[3]), in conducting wireless network simulation is the vast number of events generated, a majority of which are related to signal transmission in the PHY/MAC layers.In this extended abstract, we investigate the operations of signal transmission in the various stages: signal propagation, signal interference, and interaction with the PHY/MAC layers, and identify where events can be reduced without impairing the accuracy. We propose to leverage the MAC/PHY state information, and devise (from the perspective of network simulation) a reactive channel model (RCM) in which nodes explicitly register their interests in receiving certain events according to the MAC/PHY states they are in and the corresponding operations that should be performed. The simulation study indicates that RCM renders an order of magnitude of speed-up without compromising the accuracy of simulation results. An advantage of RCM with respect to the implementation is that there is no need to re-design the channel model for each specific MAC layer, and the modification made in the MAC/PHY layers is quite modest (e.g., a few API changes). This, coupled with the performance gain, suggests that RCM is an attractive, light-weight mechanism for expediting wireless network simulation.