Angular–Temporal Validation of Deterministic Digital Twins for Indoor FR3 Channel Modeling

Abstract

This paper presents a measurement-driven assessment of a deterministic Digital Twin (DT) for indoor radio propagation in the 10-15 GHz sub-band of the Frequency Range 3 (FR3) band, which covers from 7 to 24 GHz, using angular-temporal channel metrics derived from directional measurements. An indoor measurement campaign is conducted with an omnidirectional transmitter and a horn antenna at the receiver, rotated in azimuth to capture angularly resolved channel responses. The environment is reconstructed using a ray-tracing-based DT with frequency-dependent material modeling following ITU-R recommendations. The measured channels are compared against simulated channel responses obtained from the deterministic ray-tracing framework using complementary metrics, including Power Delay Profiles, Power Angular Profiles, RMS delay spread, and synthetic omnidi-rectional responses. The results show that the DT reproduces the dominant multipath components across receiver rotations, including their delay stability and angular evolution, while the remaining power variations are primarily driven by antenna directivity. Although minor discrepancies arise from limitations in material characterization and diffuse scattering modeling, the DT accurately captures the angular dependence and average delay-dispersion behavior, demonstrating the suitability of angular-temporal validation for FR3 DT assessment.