Experimental Analysis of Depolarization Effects of Infrastructure-to-Vehicle Radio Channels

This paper presents an experimental analysis of the depolarization effects that multipath propagation produces on radio-frequency (RF) signals. The analysis is based on the results of a measurement campaign conducted in a suburban scenario in the city of San Luis Potos ' i, M ' exico. Such a campaign collected empirical data of the instantaneous power and Doppler power spectrum (DPS) of an infrastructure-to-vehicle (I2V) channel at 2.45 GHz. The measured data were used to compute three different cross-polarization discriminators (XPD). One of such discriminators has been widely used in the literature to assess the power ratio between co-polarized and cross-polarized signals. The other two discriminators, which are based on the Doppler shift ratio and Doppler spread ratio, are introduced in this paper as new figures of merit to measure the impact of multipath depolarization on the frequency-dispersion characteristics of vehicular RF channels. The results demonstrate that the crosspolarized multipath components of the I2V channel response produce a Doppler frequency dispersion similar to that of the co-polarized components.