A location determining method 200 for sensor apparatus placements in building includes: a step in which a first measuring device transmits a digitally modulated first test packet through a specific channel at a first location in a building (210); a step in which a second measuring device receives the first test packet and transmits a first echo back signal through the specific channel at a second location in the building (220); a step in which the first measuring device receives the first echo back signal transmitted from the second measuring device and measures a first channel quality of the specific channel based on the first echo back signal (230); a step in which the first measuring device transmits a digitally modulated second test packet through the specific channel (240); a step in which the second measuring device receives the second test packet and transmits a second echo back signal through the specific channel (250); and a step in which the first measuring device receives the second echo back signal transmitted from the second measuring device and measures a second channel quality of the specific channel based on the second echo back signal (260).