  In wireless networking R&D we typically depend on simulation and
experimentation to evaluate and validate new networking solutions. While
simulations allow full control over the scenario conditions, real-world
experiments are influenced by external random phenomena and may produce hardly
repeatable and reproducible results, impacting the validation of the solution
under evaluation. Previously, we have proposed the Trace-based Simulation (TS)
approach to address the problem. TS uses traces of radio link quality and
position of nodes to accurately reproduce past experiments in ns-3. Yet, in its
current version, the TS approach is not compatible with scenarios where the
radio spectrum is shared with concurrent networks, as it does not reproduce
their channel occupancy. In this paper, we introduce the
InterferencePropagationLossModel and a modified MacLow to allow reproducing the
channel occupancy experienced in past experiments. To validate the proposed
models, the network throughput was measured in different experiments performed
in the w-iLab.t testbed, controlling the channel occupancy introduced by
concurrent networks. The experimental results were then compared with the
network throughput achieved using the improved TS approach, the legacy TS
approach, and pure simulation, validating the new proposed models and
confirming their relevance to reproduce experiments previously executed in real
environments.
