PhyTraces: Simulating New RF Environments with Physical Layer Traces

Wireless systems are deployed in environments like buildings, bridges and forests - each of which has very different wireless properties. In this paper, we propose a technique to customize simulation for a new RF environment, before a physical layer model has been created for it. Our approach is to create physical layer traces or PhyTraces that capture the RF environment of a single node. These PhyTraces can then be composed in multiple ways to simulate protocol-layer performance in the target environment. This approach offers an alternative to conventional trace-based network simulation that is very realistic, but does not permit protocol-level changes after the traces are collected. We show that PhyTraces can be collected very quickly and can be used in simulation with low computational overhead to model networks of various sizes and densities. To evaluate this approach, we collect PhyTraces in 3 different physical environments using 2 different low-power radios at 4 different transmission power levels. Our analysis indicates that the PhyTraces can predict the performance of neighbor discovery algorithms, distance vector routing algorithms, and flooding algorithms in real deployments, including some effects of complex dynamics due to packet loss and wireless collisions.