We introduce a general approach to characterize
composite fading models based on inverse gamma (IG) shadowing. We first determine to what extent the IG distribution is an
adequate choice for modeling shadow fading, by means of a comprehensive test with field measurements and other distributions
conventionally used for this purpose. Then, we prove that the
probability density function and cumulative distribution function
of any IG-based composite fading model are directly expressed
in terms of a Laplace-domain statistic of the underlying fast
fading model and, in some relevant cases, as a mixture of wellknown state-of-the-art distributions. Also, exact and asymptotic
expressions for the outage probability are provided, which are
valid for any choice of baseline fading distribution. Finally,
we exemplify our approach by presenting several application
examples for IG-based composite fading models, for which their
statistical characterization is directly obtained in a simple form.
