CONCEPTS AND RESULTS FOR 3D DIGITAL TERRAIN-BASED WAVE-PROPAGATION MODELS - AN OVERVIEW

Mobile communication links are severely influenced by propagation effe cts. Wave propagation in the VHF/UHF frequency range over natural and man-made terrain is strongly dependent on topography and morphography. Propagation modeling is based on a ray-optical approach. Wave interac tions, like diffraction and scattering, over the propagation path are described by the uniform theory of diffraction and physical optics. St ate-of-the-art propagation models for rural and urban areas are presen ted for 2D and 3D ray tracing. Near-range models apply for the corresp onding areas in forest and urban sites. The fieldstrength delay spectr um describes ray contributions with deterministic amplitudes but stati stical phases are used to derive time- and frequency-domain channel ch aracteristics. Comparisons between measured and predicted data are pre sented.