  Unmanned aerial vehicle (UAV) aided millimeter wave (mmWave) technologies
have a promising prospect in the future communication networks. By considering
the factors of three-dimensional (3D) scattering space, 3D trajectory, and 3D
antenna array, a non-stationary channel model for UAV-to-vehicle (U2V) mmWave
communications is proposed. The computation and generation methods of channel
parameters including interpath and intra-path are analyzed in detail. The
inter-path parameters are calculated in a deterministic way, while the
parameters of intra-path rays are generated in a stochastic way. The
statistical properties are obtained by using a Gaussian mixture model (GMM) on
the massive ray tracing (RT) data. Then, a modified method of equal areas
(MMEA) is developed to generate the random intra-path variables. Meanwhile, to
reduce the complexity of RT method, the 3D propagation space is reconstructed
based on the user-defined digital map. The simulated and analyzed results show
that the proposed model and generation method can reproduce non-stationary U2V
channels in accord with U2V scenarios. The generated statistical properties are
consistent with the theoretical and measured ones as well.
