CaST: A Toolchain for Creating and Characterizing Realistic Wireless Network Emulation Scenarios

Large-scale wireless testbeds are being increasingly used in developing and evaluating new solutions for next generation wireless networks. Among others, high-fidelity FPGA-based emulation platforms have unique capabilities for faithfully modeling real-world wireless environments in real-time and at scale, while guaranteeing repeatability. However, the reliability of the solutions tested on emulation platforms heavily depends on the precision of the emulation process, which is often overlooked. To address this unmet need in wireless network emulator-based experiments, in this paper we present CaST, a Channel emulation generator and Sounder Toolchain for creating and characterizing realistic wireless network scenarios with high accuracy. CaST consists of (i) a framework for creating mobile wireless scenarios from ray-tracing models for FPGA-based emulation platforms, and (ii) a containerized Software Defined Radio-based channel sounder to precisely characterize the emulated channels. We demonstrate the use of CaST by designing, deploying and validating multi-path mobile scenarios on Colosseum, the world's largest wireless network emulator. Results show that CaST achieves <= 20 ns accuracy in sounding Channel Impulse Response tap delays, and 0.5 dB accuracy in measuring tap gains.