Level Crossing Rate and Average Fade Distance of Signal Scattering From Rough Layered Interfaces

In this paper, we study the level crossing rate (LCR) and the average fade distance (AFD) of signal scattering from layered rough surfaces. First, we implement the first-order perturbation method, and we establish the analytical expression of the joint probability density function (PDF) of the modulus of the field filtered by a sensor and its spatial derivative. We also consider the case of the field intensity. Then, we derive from the joint PDF the closed-form formulas for the LCR and the AFD as functions of the statistical parameters of rough interfaces. Numerical simulations are conducted to validate the theoretical results and show that the second-order descriptors are very sensitive to the values of cross-correlation parameters of rough interfaces.