HAPS propagation loss model for urban and suburban environments

High-Altitude Platform Station (HAPS), which provides communication services from an altitude of 20 km via an Unmanned Aerial Vehicle (UAV), is attracting much attention as a new mobile communications platform for ultra-wide coverage areas and disaster-resilient networks. A HAPS can provide mobile communications services directly to smartphones. In order to design efficient cell configurations for HAPS-based services, we need a radio wave propagation model that takes into consideration factors such as terrain, vegetation, urban areas, suburban areas, and building entry loss. In this paper, we focus on the propagation loss at high elevation angles in urban and suburban areas. We measure and clarify the propagation loss characteristics at high elevation angles in urban and suburban areas and propose a new model based on the current clutter loss model.