Diffuse Scattering Model of Indoor Wideband Propagation

This paper presents a discrete-time numerical algorithm
for computing field distribution in indoor environment by
diffuse scattering from walls. Calculations are performed for a
rectangular room with semi-reflective walls. The walls are divided
into 0.5 x 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
finite period of initial excitation the field intensity in all locations
eventually follows 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 dB, 19.4 dB and 20.2 dB
per 100 ns, respectively. The remaining differences are further
discussed and an additional case of 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.