An Approximate Numerical Model for Simulation of Long-Distance Near-Ground Radiowave Propagation over Random Terrain Profiles

A numerical solver for analyzing long-distance near-ground radiowave propagation over a randomly rough terrain surface is described. As the rough terrain section located in between but in the far field of the transmitter and receiver points appears to be electrically flat to the forward propagating wave, an approximate simplified model is derived with the replacement of this section with a physically flat section of an effective height, resulting in a problem with three physical sub-domains. This model implies that the mean received power and its fluctuation are primarily dictated by the statistics of the rough terrain local to the transmitter and receiver. Wave propagation over the three sub-domains is solved using a recursive, 2D Nyström-discretized-integral-equation-based forward marching scheme. Since the majority of the final terrain profile is flat and over which field interactions can be cast in terms of a block-Toeplitz matrix, large memory savings and computational speedup are achieved. The accuracy of the three-sub-domain model is demonstrated, and simulation results for the path-loss of LOS and NLOS (non-line-of-sight) links are presented for rough terrain with various random statistics. The new solver as detailed here is an attractive tool for simulating radio coverage for near-ground wireless networks.