A Semi-Deterministic Model for Outdoor-to-Indoor Prediction in Urban Areas

The prediction of indoor coverage from outdoor base stations should be of even greater interest than outdoor prediction, as most wireless data traffic is generated indoors. Due to difficulties in acquiring indoor building maps on a large scale and integrating outdoor and indoor propagation models, outdoor-to-indoor prediction has been limited in practice 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 3-D outdoor prediction on building surfaces and indoor extension using a radiosity-based iterative method that does not require a detailed building map. Prediction results are checked against measurements and, surprisingly, they appear to be almost as accurate as outdoor prediction results.