Abstract

This material is dedicated to the rather old, but always actual, topic in theoretical analysis of applied problems: how to simplify an analytical investigation by applying multidimensional Probability Density Functions (n-PDFs). A brief overview of the applied interpretations for n-PDF approximation is presented, which allows to make choice of the practically useful analytical presentations for n-PDFs. For analytical solutions, two approximations for the n-PDF were chosen: Poli-Gaussian approximation (mix of Gaussian PDF's) and Functional Approximation or Gaussian-like. The first one is found to be suitable (and is recommended) for the class of scenarios better described by the term "scenarios of random structure". The second seems to be more adequate for analysis of the numerical characteristics of the communication system's behavior Recommendations for validation of the models with given n-PDF approximations, based on goodness of fit criteria's can be found as well.