A Semi-Deterministic Method For Predicting Indoor Cellular Coverage In Dense Urban Areas

The prediction of cellular RF coverage at street level in urban environment has been addressed in many studies in the past two decades. Nevertheless, the prediction of indoor coverage on upper floors, much less popular within the scientific community, is of even greater interest, as most of the traffic of outdoor cellular base stations actually comes from indoor users.Due to difficulties in acquiring extensive indoor environment databases and using simultaneously outdoor and indoor propagation models, prediction of indoor coverage from outdoor base stations has been mainly limited to the use of generic outdoor-to-indoor attenuation factors or empirical formulas.In the present work, we propose a hybrid method based on deterministic 3D outdoor RF prediction on the building surfaces and indoor extension using a radiosity-based method. Prediction results are checked against measurements and, surprisingly, results appear to be as accurate indoors on upper floors as outdoors at street level.