A general correlation model for shadow fading in mobile radio systems

In this letter we derive an explicit model for the cross-correlation function of the shadowing components affecting the links between a mobile station and two base stations. This model includes both the autocorrelation model proposed in earlier work by Gudmenson in 1991 for the single component, and the cross-correlation early evidenced in the work by Graziano in 1978. The model is useful in analytical computations, e.g., of second order statistics of signal-to-interference ratio. The model can include the behavior of a time-variant cross-correlation at zero-time shift and of a non-homogeneous environment.