An FFT multiple half-screen diffraction model

A physical path loss propagation model for macro cells is described. The terrain profile is replaced with a number of absorbing half-screens, where the edges coincide with the average height of the surrounding obstacles. The propagation is then treated as a multiple diffraction phenomenon where reflections are neglected. The diffracted scalar field is determined by using the Helmholtz integral equation which for the actual geometry can be expressed as a convolution. This makes it possible to increase the computational efficiency considerably by determining the Fourier transform and replacing the convolution with a product