Multi channel coupling: interactive prediction of 3D indoor propagation

The planning of an indoor mobile communication system can be a difficult task that involves many trial installations of base stations. It is desirable to replace such trial installations by computer simulations. We present in this paper an algorithm that allows a fast and interactive deterministic prediction of three-dimensional field strength maps. With this tool it is possible to quickly find an efficient placement of base stations for the required coverage in a building complex. The simulated environment is modeled as a large network of geometric channels that contain the propagated signal. The calculation of the local coupling between the channels can be carried out in advance because it does not depend on transmitter and receiver positions. In a second step, field strength maps are calculated interactively for arbitrary transmitter and receiver configurations based on the geometric information stored in the channel coupling coefficients. Since the concept of a channel network allows the implementation of global energy conservation, the prediction is expected to provide optimal robustness against details in the description of the building. This is demonstrated by the comparison of the predictions in different three-dimensional building structures to corresponding measurements of the fading-averaged field strength.