Stochastic models for short-term multipath fading channels:chi-square and Ornstein-Uhlenbeck processes

摘要

This paper discusses the use of stochastic differential equationsto model signal envelope variations over areas, which are subject toshort-term fading effects. The short-term fading effects are modeledusing Ornstein-Uhlenbeck processes and they are derived from firstprinciples, using the scattering assumption of electromagnetic waves.This gives rise to signal envelope variations which follow amean-reverting square-root process, which is elastically pulled towardsa long-term mean which characterizes the propagation environment. Thederived signal envelope distributions include generalizations ofRayleigh, Rician, Nakagami etc. distributions to their nonstationaryanalogs and thus generalizing channel models to include time variations.From these computations the second order statistics of the receivedsignal are obtained