Effect of reflected waves from outdoor buildings on outdoor-to-indoor path loss in 0.8 to 37 GHz band

The measurement results of outdoor-to-indoor path loss characteristics in multiple frequency bands from microwave to millimeter wave are described. We clarified that the path loss characteristics dependence on frequency. Moreover, ray tracing is used to analyze the propagation phenomena causing frequency dependence. A comparison between measured and calculated results clarified the dominant paths that is multiple reflected at an outdoor building and then diffracted into building. These results show that the value of the root mean square error is about from 4 dB to 8 dB in 0.8 to 37 GHz band. We confirm that these paths are dominant and affect the frequency dependence of outdoor-to-indoor path loss.