The Flexibility of the Generalized Gamma Distribution in Modeling the Fading Based on Kullback-Leibler and Kolmogorov-Smirnov Criteria

The precision of Rayleigh distribution, as the simplest fading model in Non-Line-of-Sight (NLOS) channels, is low in high-resolution radars and long-distance communication receivers. Many currently-available statistical models with a higher precision, including Nakagami-m, Weibull and generalized hybrid Gamma models, are used to describe the radar clutter and the reflected signals in communication receivers. Although the mentioned models in NLOS channels have more accurate matching with the actual fading, a variety of models and the lack of a comprehensive model in different fading channels make it difficult to select an appropriate model. In this paper, the generalized Gamma model is analyzed and evaluated to demonstrate that it adapts to other fading models. Moreover, it also matches with long-term fading, as well as combined long and short-term fading models. Using a practical sample, it is stated that the generalized Gamma model is also adaptable to the channels to which none of the other available closed-form models are suitable. The simulations and the real data results, approved by Kullback-Leibler and Kolmogorov-Smirnov criteria, prove the claim.