Zizo if you have not read the follow book, read:
Multipath Phenomena by Blaunstein & Andersen ISBN 1-58053-185-7 Published by Artech House.
Many chapters dedicated to various forms of fading, and Chapter 4 Distribution of Angle of Arrival and Time Delay from an Array of Buildings Placed on Rough Terrain… has some interesting discussion on PDF (probability density function) and LOS & NLOS conditions