"Shout Measurements with POWDER Dense Deployment Nodes and Sionna Ray Tracing Data for Channel Impulse Response Comparison"

"Next-generation wireless networks will rely on advances in digital twins to model and predict behavior in networks. Ray tracing (RT) is proposed for high-accuracy digital twinning of the multipath radio channel. We present a comparative analysis between channel impulse response (CIR) measurements collected on the Platform for Open Wireless Data-driven Experimental Research (POWDER), a large-scale real-world wireless testbed, and the equivalent CIR predictions generated with Sionna ray tracing (Sionna RT) software. We apply multiple processing algorithms to superimpose and compare the measured and predicted CIRs. Our study highlights similarities and differences, including time of arrival and amplitude statistics of multipath components, as well as the total received power and RMS delay spread of the channel as a whole. We find that, while total powers of the multipath in the measured and RT CIRs have a strong correlation of r=0.85, the RMS delay spreads of the two CIRs are weakly correlated with r=-0.35, showing that ray tracing is largely unable to predict the delay spread of the measured channel. Across the network, only 10% of measured multipath were predicted by ray tracing, with the largest percent of the accurately predicted multipath arriving within 100 ns before and after the maximum path. We analyze factors that can contribute to differences in signal behavior between the two sources, including misalignment in GPS coordinates and building placement in the digital twin rendered scene, mobile objects, and environmental impacts."