Dual-Polarized MIMO UAV-to-Ground Tree Shadowed Channel: Capacity, Multiplexing, Stationarity, and Statistical Modeling Assessment

Abstract

This article presents an extensive performance analysis of a narrowband dual-polarized (DP) multiple-input-multiple-output (MIMO) communication link, between a low-altitude unmanned aerial vehicle (UAV) and a terrestrial terminal. The experimental campaign is conducted in an urban park, under tree shadowing environment. The ergodic capacities are calculated 5.2 b/s/Hz for line-of-sight (LOS), and 4.4 b/s/Hz for nonline-of-sight (NLOS) trajectories, respectively, substantially enhanced compared with the single-input-single-output (SISO) cases. The encountered capacity variations are associated with the propagation geometry and the UAV flight path, as well as with the elevation angle and distance between the related terminals. From the multiplexing assessment analysis, the DP-MIMO channel has been shown its favorability for adopting beamforming methods. A new stochastic model is also suggested that represents the channel matrix employing jointly the inverse Gaussian and Rayleigh distributions. Promising results are delivered, where the adopted model predicts conveniently the channel capacity under the existence of tree shadowing. Finally, shorter stationarity periods are observed under the tree presence affecting their pattern and, in respect, the achieved instantaneous capacity.