Modeling Time-Variant Multipath Number for Geometry-Based Stochastic UAV-to-Ground Channel Model in a Typical Rural Area

Understanding and modeling of the characteristics of multipath transmission of unmanned aerial vehicle (UAV) air-to-ground (A2G) wireless signal in complex environment play pivotal roles in the development of A2G communication and positioning applications. Traditional geometry-based stochastic channel model (GSCM) simulates the birth-death process of individual multipath components (MPCs) via the concept of visible region, which is complex in parametrization. In this letter, we present an extended A2G channel model by combining the GSCM with 4-state Markov model by which the birth-death process of MPCs is controlled. Time variant channel parameters are tracked by combining space-alternating generalized expectation-maximization (SAGE) method with the autoregressive moving average (ARMA) filter. The proposed model is validated by comparing the channel characteristics based on simulation results with the measurement data.