Physical Modeling Of Autocorrelation Functions Of Shadow Fading In Mobile Radio Systems

In this Thesis,a novel approach is introduced in order to address the radio channel shadow fading modeling problem.The modeling is based on the physics of the prop-agation environment through which the electromagnetic waves pass.To the best of the author's knowledge,lumped circuit theory has not been applied previously to radio channel modeling in the literature.However,under certain conditions on the propaga-tion environment and propagating radio waves,a circuit theory based modeling can be utilized.Among various deleterious effects of a radio channel on a propagating electromagnetic wave,this thesis focuses on the shadow fading(shadowing)effect.Shadow fading is mathematically modeled as a multiplicative random gain which exists due to the pres-ence of large scale obstacles in the propagation environment.Moreover,one can study various characteristics of a random phenomenon,for instance first-order probability dis-tribution function(PDF),ergodicity,etc.;in this work,the autocorrelation function of shadow fading is of particular interest.A flexible general model for the autocorrelation functions of shadow fading in radio chan-nels is derived.This model can explain most of the previous widely used models in the literature.Such a general model,weighted exponentials,for the autocorrelation func-tion can be implemented in radio channel measurement equipment and improve both the evaluation and design of wireless transceivers,specially the mobile transceivers.