Temporal Characterization of Fade Events in mmWave Channels

Abstract

Millimeter-wave communication systems operate under propagation conditions markedly different from those observed at lower frequencies, characterized by increased path loss, reduced effective scattering, and a strong dependence on line-of-sight links. Under such conditions, an accurate temporal characterization of fade events becomes essential for assessing link reliability and dynamic performance. This paper investigates the temporal behavior of fading in millimeter-wave channels by analyzing the recurrence and persistence of envelope fluctuations across a range of normalized threshold levels. A modeling approach is adopted in which fast envelope variations are described through a conditional formulation, while slower channel fluctuations are incorporated via a latent-scale mechanism, naturally accommodating uncertainty through a Bayesian modeling perspective. The resulting envelope representation enables a consistent evaluation of temporal fading metrics without relying on derivative-based assumptions. Analytical and semi-analytical formulations are obtained for key quantities associated with fade events, including the cumulative behavior of the envelope, the frequency of level crossings, and the average duration of fades. Numerical results based on Monte Carlo simulations are presented and compared with commonly adopted fading models, allowing a direct assessment of the predicted temporal dynamics under millimeter-wave propagation conditions. The results demonstrate that the proposed formulation captures the combined effects of rapid signal fluctuations and slower channel variability, providing a physically consistent basis for the temporal characterization of fade events in high-frequency wireless channels.