nce this propagation means of a Monte Carlo approach. In particular, DS, AS, environment is close to the case of isotropic scattering. finger life statistics in rake receivers and other statistics A different approach, which can be used to derive are obtained and reported VS. environment characteris- local fading statistics (including the expected mean tics, building height statistics, etc. level), is presented in [NaCB04]. For network planning In [TLVD01] fading statistics are obtained by RT sim- purposes, it is of interest to estimate the expected local ulations. In particular, starting from the multipath in- mean level. Due to multipath fading (often referred to as formation at one single point, it is possible to estimate the Rayleigh fading), it is necessary to average large blocks signal statistics in a local area of that point, therefore an (10% X 10%) of hundreds of points separated by a frac- efficient site-specific channel model might be feasible. tion of wavelength (e.g. N/4) to estimate the local mean Using the RT technique, the Doppler power spectral level, and this can require enormous computational density S(f) for a receiver which is assumed to be moving in a certain direction with a given velocity can be computed K-factor estimation from direction of arrival and intensity of each path. Moreover, making use of the phase of each wave Ok, the * method 1 complex function R(f), where |R(f) 2 = S(f), can be de- measurements rived and the complex envelope of the received signal in method 3 the time domain can be obtained by simply performing the inverse Fourier transform of R(f). This process is ob- viously much faster than the simulation of the received signal in a great number of locations (denoted as method 1 in this work). Finally, once the complex envelope of the received signal in the time domain r (t) is known, the spatial distribution of the fades is obtained by considering that time and space are obviously related by the velocity (see formula (4.7.3)). The fast fading statistics in a local area 