 rooftop propagation models. Moreover, environment pitals in the frequency range from 600 MHz to 5.2 GHz cluttering data (vegetation, vehicles, street signs, etc.) are is considered. What makes wave propagation in hospitals often unavailable or impractical to model. While re- different from that in other buildings is the special con- liability must be considered a very advisable quality, the struction of their walls. Some of these walls contain 'level of detail' is not necessarily SO. A great level of detail metallic layers, e.g. operating rooms with CrNi-steel (sometimes confused with 'accuracy') means the pres- faced walls, X-ray rooms with lead shielded walls or ence of a great deal of building elements (internal yards, Magnetic Resonance Tomography (MRTo) rooms with indentations, edges, roof structures, etc.) which, although Electro-Magnetic Compatibility (EMC) shielded walls relatively irrelevant, can still greatly increase the size of made of a copper foil. If the real conductivity of those the database, with a more than proportional increase in metals (copper, lead, CrNi-steel) were used in the sim- the computation time of the prediction. Therefore, geo- ulations, this would lead to an infinite shielding of the metric databases must often be properly 'purged' or walls, because slots and openings in the metallic layers simplified before they can be input to deterministic cannot be taken into account. For this reason, the effective propagation models. constitutive parameters of each kind of wall were In the indoor case, the description of floor and room determined through multiple measurements of single partitions of the buildings in AutoCAD's native file format wall attenuation in different hospitals and double for CAD models (DWG) or Data Exchange Format checked by comparison between measurement and sim- (DXF) can often be extracted from the architectural ulation of attenuation between two adjacent rooms. The design files of the building. In this case the accuracy of the attenuation of single walls was mea