In the scope of very high‐frequency (VHF) and ultra high‐frequency (UHF) terrestrial communication or broadcasting systems planning, the use of point‐to‐area propagation prediction methods is expected. The benchmarking of such models on different scenarios is very helpful to assist the system planner in choosing those most suited to the site in hands. In this sense, this study provides a comparative performance analysis of the International Telecommunication Union radio communication sector (ITU‐R) recommendations P.526, P.1546, and P.1812 and a few other models on a site marked by the presence of irregular terrain covered by forest. A set of measurements at 563 MHz at different spots in Rio de Janeiro city with such features was taken as reference. The best prediction performance was achieved by the P.526 and P.1812 methods, in addition to a wedge diffraction model, with path loss mean errors between −5 and 3 dB, and standard deviations between 8.7 and 9.2 dB. Such results were observed when the presence of the forest layer was incorporated adding a representative clutter height.
Irregular terrains covered with forest vegetation represent a challenging scenario for radio planning. A case of particular interest is the one where a forest-covered high hill or mountain is interposed to the link, for which typical diffraction loss models usually apply as good approximations, even disregarding the vegetation influence. Pragmatic approaches to incorporate the forest contribution, such as adding a clutter height, usually improve accuracy a little further. In this scope, this paper assesses the performance of some models based on the Uniform Theory of Diffraction (UTD) for RF path loss prediction in such ridges. Special attention goes to a hybrid model in which the forest is a uniform layer over a wedge that represents the ridge, and its influence is incorporated into the diffraction coefficient. The path loss predictions are compared with measurements from a mountainous region of the USA, and the statistical adherence of the models to the measured data is discussed. Overall, the slightly better performance of the models which incorporate the vegetation influence was confirmed, the hybrid model performing the best for frequencies below 910 MHz.
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