Applicability of rough surface scattering to 3D radio planning

A demonstration 3D channel prediction model was used in example scenarios in hilly terrain and undulating rural terrain. The model is comprised of a 2D vertical Tx-Rx-plane component as well as 3D components due to off-axis scattering. The latter components are found using rough surface scattering estimation. In the implementation a novel high performance scattering model called the amplitude/phase model was used. It was shown than when the vertical plane 2D prediction was attenuated more than typically 15 dB compared to free space a 3D channel model is necessary. This value was exceeded in approximately 40% of the coverage area in the hilly terrain, and in about 15% of the area in undulating rural. This leads to the conclusion that in a hilly terrain traditional 2D models are not sufficient. When the 3D components were dominating the distribution was approximately Rayleigh, with a typical difference between the 5 and 95 percentiles in the distribution of more than 15 dB. Weather and seasonal variation may change the mean received signal level by up to 4-5 dB. An erroneous assumption about the permittivity or surface roughness by a factor of two could change the mean of the received radio signal by up to 10 dB.