Discrete ray-tracing method (DRTM) analysis of propagation characteristics along random rough surface in relation to development of wireless sensor network

Discrete ray tracing method (DRTM) is applied to numerically analyze electromagnetic wave propagation along random rough surfaces. In the DRTM analysis, we make some assumptions in order to simplify the ray searching algorithm as well as to save computation time. First we discretize the rough surface in terms of linear piece wise edges (1D), and second we determine whether the two edges are on the line of sight (LOS) or not by checking whether two representative points on the two edges can be seen each other or not. Diffraction rays are also determined by this algorithm. In the numerical computation, we neglect multiple diffractions or higher order of scattered waves in terms of between edges. As for reflection, we include reflection rays having at most two times reflections at the source side and two times reflections at the receiver side. Numerical examples are given for ray examples and propagation characteristics along three types of rough surfaces.