Time Non-Stationary RS-GBSM for UAV Narrowband Channels

To capture the time non-stationarity of UAV narrowband channels, a novel three-dimensional (3D) non-stationary model for non-isotropic unmanned aerial vehicle (UAV) multiple-input multiple-output (MIMO) Ricean fading channels are proposed. The proposed geometry-based stochastic model (GBSM) employs a two-cylinder model, where the signal is a superposition of line-of-sight (LoS) component, single-bounced rays around the UAV, single-bounced (SB) rays around the ground station (GS), SB rays on the ground, and double-bounced (DB) rays. The time non-stationarity is reflected on the time-varying angles of departure (AoDs) and angles of arrival (AoAs). Since we consider the GS to be mobile, the proposed 3D GBSM is general and suitable for UAV-aided vehicular communication scenarios. Based on the proposed model, some important channel statistical properties are derived and thoroughly investigated, including the space-time correlation function (STCF), Doppler power spectral density (PSD), envelope level crossing rate (LCR), and average fade duration (AFD). Moreover, our model has the ability to investigate the influence of some unique UAV-related parameters on channel characteristics and time non-stationarity. Finally, the excellent agreement is achieved between the reference model and simulation models, demonstrating the feasibility of simulation models as well as the correctness of theoretical derivations.