A non-stationary multipath fading channel model incorporating the effect of velocity variations of the mobile station

Abstract

A standard assumption in mobile fading channel modelling is that the mobile station (MS) moves along a straight line with constant speed. In practice, this assumption is violated in most propagation scenarios. For the development of more realistic channel models, it is therefore important to relax this restriction by allowing the MS to change its velocity. In this paper, we study the effect of velocity changes on the statistical properties of multipath fading channels. Expressions will be derived for the local autocorrelation function (ACF), the Wigner-Ville spectrum, the average Doppler shift, and the Doppler spread. Our findings show that a variation of the speed and/or the direction of the MS results in a non-stationary channel model. The Wigner-Ville spectrum cannot be interpreted physically as a generalized Jakes (Clarke) power spectral density (PSD); although it includes the latter one for the special case that the MS moves with constant velocity.