On the validity of the slow and moderate fading models for matched filter detection of Rayleigh fading signals

Published analyses of data transmission on flat fading channels often assume that the pulses arrive without distortion, and that random amplitude and phase are applied on a per-pulse basis. In reality, however, multiplicative distortion in the channel operates over each pulse. If the receiver uses a matched filter, an error floor results even for isolated pulse transmission. The author examines the effect systematically. By obtaining the error floor as a function of fade rate and pulse roll-off, he defines the limits, or `safe zone,' of the distortion-free approximation, which is here termed the moderate fading model. The results should be of interest to those working in modelling and analysis of fast fading channels.