On Second-Order Fading Statistics of Multi-Antenna 3-D Vehicular Communication Channels

Incorporating systems that have multiple antennas with an inherent capability of reconfigurable beam patterns can enhance vehicle-to-vehicle (V2V) communications in 6G networks by taking advantage of favorable channel conditions. To achieve the full potential of multiple antennas, it is of paramount importance to accurately express the relationship between the received signal envelope and the underlying 3-D spatio-temporal configuration of the channel. We propose an improved 3-D spatio-temporal configuration of V2V radio propagation channels and then provide detailed analytical insights into the fading characteristics of the received signal envelope. Although, first-order statistics describe the distribution of received signal amplitudes but do not capture their variation over time. In contrast, second-order statistics such as level crossing rate (LCR) and average fade duration (AFD) show how fades occur and persist over time. In this context, we analyze the impact of different system and channel parameters (such as mobility condition and composition of scattering region) on the second-order fading statistics of the received signal envelope by exploiting the theory of 3-D multipath shape factors. Further, we investigate the impact of notable physical and geometric channel parameters on angular, temporal, and envelop fading statistics. Finally, we validate the expressions derived by comparing the Monte Carlo simulation results with empirical datasets available in the literature and demonstrate the accuracy and applicability of our proposed model.