Temporal Autocorrelation Properties of Three Dimensional Vehicle-to -Vehicle Channels in the Presence of Moving Scatterers

This paper derives the analytical expression of the temporal autocorrelation function (ACF) of the non-stationary three dimensional (3D) multipath scattering channels, in which scatterers move with constant velocities in random directions around transceivers. The analytical expression involves high dimensional integration within finite interval, thus a methodology based on ray-tracing is proposed to carry out its numerical solution. The analytical expression and the corresponding ray-tracing based model serve as the canonical forms for the correlation analysis of non-stationary 3D multipath scattering channels, which include two special cases: two dimensional (2D) multipath scattering and stationary multipath scattering. Numerical results show that: in case of nonstationary 3D multipath scattering, with the increase of the velocity and the density of scatterers, the temporal ACF would attenuate more rapidly. These results would allow engineers more appropriate determination on coherence time and coherence bandwidth for vehicle-to-vehicle communication systems.