Communication Software Execution Model of a WSN Device for More Accurate Simulation in ns-3

Emerging infrastructure-less network architectures such as WSNs consist of devices that perform packet processing in software. General-purpose network simulators do currently not possess models to simulate the intra-node delay of such devices. A TelosB mote with TinyOS spends seven and fifteen ms on processing packets of size 36 and 124 bytes. Failing to simulate this leads to an inaccurate simulation of packet loss, jitter, and latency. In this work, we create a communication software execution model of TelosB that accounts for its temporal behavior for more accurate WSN simulations in the ns-3 simulator. A challenge in doing so is to create a tracing framework for TinyOS that can be used to accurately and reliably trace its behavior. The evaluation of our model shows that it is scalable and accurate; the simulated intra-OS delay deviates at most 5% from the intra-OS delay in the real mote. Moreover, the real mote and our model both start to drop packets at 65kbps (124 bytes packets), while the original ns-3 model starts dropping packets at 101kbps. This 36% decrease in forwarding capacity demonstrates that our model enables significantly more accurate simulations.