This paper presents an efficient ray-launching method for 2D indoor propagation problem, by including crucial multiple reflection effect inside wall. We here focus on the derivation of the reflected and transmitted ray solutions at/through wall when a magnetic source is located in the indoor environment. An efficient approximation, which is called collective ray approximation, is carried out to bundle or collect the internal multiple reflected rays into the primary one. It is resultantly confirmed from the detailed numerical experiments that the derived collective ray solutions can be confidently effective when the internal reflections strongly contribute to the propagation characteristic in the propagation environment, regardless of angle of the incidence.

This paper deals with a TM plane wave reflection and transmission from a one-dimensional random slab with stratified fluctuation by means of the stochastic functional approach. Based on a previous manner [IEICE Trans. Electron. E88-C, 4, pp.713-720, 2005], an explicit form of the random wavefield is obtained in terms of a Wiener-Hermite expansion with approximate expansion coefficients (Wiener kernels) under small fluctuation. The optical theorem and coherent reflection coefficient are illustrated in figures for several physical parameters. It is then found that the optical theorem by use of the first two or three order Wiener kernels holds with good accuracy and a shift of Brewster's angle appears in the coherent reflection.

The mean reflection and transmission coefficients of electromagnetic waves incident onto a two-dimensional slightly random dielectric surface are investigated by means of the stochastic functional approach. We discuss the shift of Brewster's scattering angle using the Wiener kernels and numerical calculations. It is also shown that the phase shift at the reflection into Brewster's angle for a flat surface does not depend on the rms height of the surface, but does on the correlation length of the surface.