Evaluation of an Outdoor-to-in-Car Radio Channel with a Four-Antenna Handset and a User Phantom

Based on static outdoor channel measurements we evaluate the influence of a vehicle on the MIMO radio channel, from a base station antenna array, to a multiple antenna handset in the hand of a user placed inside a test car. The measurement scenario is chosen to mimic a 2.6 GHz (LTE) macro-cell urban or rural scenario with two locations and orientations of the car, one at an open parking lot with a strong line-of-sight component, and one between buildings with no line-of-sight. The measurements are repeated several times with the user phantom plus handset positioned at the same spot within the car and with the car absent. Figures of the penetration loss, impact on fading statistics, mean delay, delay spread, terminal antenna correlation, eigenvalue distributions, as well as the performance of various hybrid diversity combining and spatial multiplexing schemes, are evaluated and compared with and without the vehicle present. It is found that the car make the channel statistics become more Rayleigh like and increases multipath channel richness, improving the potential of diversity gain and, to some extent, spatial multiplexing.