Empirical 3-D Channel Modeling for Cellular-Connected UAVs: A Triple-Layer Machine Learning Approach. - Haider A. H. Alobaidy; Mehran Behjati; Rosdiadee Nordin; Muhammad Aidiel Zulkifley; Nor Fadzilah Abdullah; Nur Fahimah Mat Salleh (IEEE Open J. Commun. Soc., 2025)