Introduction
In mobile communication systems, the RF signal propagates from the transmitter to the receiver via multiple different paths due to the obstacles and reflectors existing in the wireless channel. These multipaths are caused by mechanisms of reflection, diffraction, and scattering from buildings, structures, and other obstacles existing in the propagation environment. Multipath propagation is usually described by line of sight (LOS) path and non line of sight (NLOS) paths as shown in Figure 1.