Application of spectral acceleration forward-backward method for propagation over terrain

Abstract

Mobile radio planning requires the accurate prediction of electromagnetic eld strengths over large terrain pro les. However, numerical methods, like MoM, become not suitable for electrically large surfaces, because of the O(N3) computational cost due to the large number of surface unknowns N. The Forward- Backward Method (FBM) is a stationary iterative technique for solving linear equation systems resulting from electromagnetic rough surface scattering problems and provides accurate results within very few iterations, causing a computational cost of O(N2). The Spectral Acceleration technique reduces the computational cost and memory requirements of the FBM to O(N), so that the Spectrally Accelerated Forward-Backward Method (FBSA) can be applied over very large terrain pro les. Empirical models with re ection and multiple di raction (RMD) corrections are commonly used to predict the eld strengths over terrain pro les. In this work, applications of the FBM and FBSA are presented over electrically large terrain pro les. Also, using FBSA as a reference solution, the most common empirical models with RMD correction methods are examined to nd out the best propagation models.