Predicting Small-Scale Fading Distributions with Finite-Difference Methods in Indoor-to-Outdoor Scenarios

Finite-difference electromagnetic methods have been used for the deterministic prediction of radio coverage in cellular networks. This paper introduces an approach that exploits the spatial power distribution obtained from these techniques to characterize the random variations of fading due to multipath propagation. Although the presented method is equally applicable to any finite-difference algorithm able of computing electromagnetic field patterns (e.g. PSTD, ParFlow, ...), it has been exemplified here by means of FDTD. Furthermore, in order to test the reliability of this approach, the predicted fading distributions are compared against real measurements in a residential indoor-to-outdoor scenario. Finally, the practical usability of this fading prediction approach is tested throughout implementation in a WiMAX femtocells system-level simulator.