METHOD FOR SIMULATING RADIO WAVE PROPAGATION, METHOD FOR ESTIMATING INTENSITY OF WAVE FIELD, AND METHOD FOR ESTIMATING THREE-DIMENSIONAL DELAY DISPERSION

摘要

Radio waves having frequencies of f1 and f2 are radiated in an area where a wireless LAN is to be set up, the radio waves f1 and f2 are separately received with an antenna which scans the surface to be observed and a fixed antenna, and their radio wave holograms are produced. Then radio wave images separated for each path are formed from the holograms, and the amplitude and delay of each path are found by finding the difference between the radio wave images. The propagation time response function x(t) of each path is found from the amplitude, delay, and the directional characteristics of the antennas and the real part and imaginary part of the function are convoluted in a modulated carrier signal y(t). Then the real and imaginary parts are respectively multiplied by the in-phase component Rf and the orthogonal component Rf* of a non-modulated carrier. Finally, a demodulated base-band signal η(t) is obtained by adding both products to each other. The radio wave time lag of each secondary radio wave image with respect to a primary radio wave source is found and the radio wave images are rearranged in an absolute three-dimensional coordinate system by using the time lags. Then the intensity of the radio waves at an arbitrary position in the absolute coordinate system is found by combining radio waves from each radio wave image and the mean value and standard deviation of the delays are found from the time lags and intensity attenuation corresponding to the distance to each radio wave image.