The site attenuations and propagation distance of radio wave intensity with 920 MHz band wireless sensors in one building (office and conference room) were clarified by measuring. In the case of -70 dBm with lower limit of radio wave intensity, the propagation distances of the office and conference room are 6.4 m and 7.3 m, respectively. It is clear that the propagation distance becomes shorter due to partitions and humans. Moreover, we could simulate the measurement result using ray tracing method, which is shown that the method is effective to predict the spatial distribution of radio wave intensity.
