A 3-D Semi-Deterministic MIMO Beam Channel Model for Cellular-Assisted Millimeter-Wave Vehicular Communications

The multiple-input–multiple-output (MIMO)-based millimeter-wave (mmWave) propagation is envisioned as a key technology to offer greater bandwidths than previously available for vehicular communications. In this article, we propose a 3-D semi-deterministic MIMO beam channel model to characterize the fading properties of cellular-assisted mmWave communications. First, we analyze the digital beamforming effects on multipaths and find that beams act like spatial filters. Then, we propose a cluster generation method, which assemblies single-bounce (SB)-based reflection points and surrounding scatterers into a group. On this basis, the SB reflection and scattering propagation mechanisms via clusters are realized by using ray tracing (RT) and propagation-graph (PG) models, respectively. Furthermore, we use the directive scattering model to enhance the modeling accuracy regarding scattering components. Based on our proposal, position and beamwidth-based channel statistical properties, including power delay profile (PDP), spatial cross correlation function (CCF), Doppler power spectrum density (PSD), and additional path loss (PL) are fully investigated considering perfect beam alignment. Numerical results show that our proposal is capable of emulating beam-dependent mmWave channel and narrow beamwidths cause few multipaths and higher PL. Besides, it can capture the nonstationarities for given scenarios, which can be adapted to various communication scenarios by establishing the corresponding digital maps.