Diffuse Scattering Model of Indoor Wideband Propagation

This paper presents a discrete-time numerical algorithm for computing field distributions in indoor environments by diffuse scattering from the walls. Calculations are performed for a rectangular room with semireflective walls. The walls are divided into 0.5 × 0.5 m segments, resulting in 2272 wall segments in total and approximately 2 min running time on average computer. Frequency independent power levels at the walls around the circumference of the room and at four receiver locations in the middle of the room are observed. It is demonstrated that after a finite period of initial excitation the field intensity in all locations eventually follows an exponential decay with the same slope and approximately the same level for given delay. These observations are shown to be in good agreement with theory and previous measurements-the slopes of the decay curves for measurement, simulation and theory are found to be 18, 19.4, and 20.2 dB per 100 ns, respectively. The remaining differences are further discussed and an additional case of a spherical room is used to demonstrate the influence of the room shape on the results. It is concluded that the presented method is valid as a simple tool for use in indoor radio coverage predictions.