Imaging of indoor multipath radio propagation for 18 GHz band wireless LAN systems: applied radio holography

Development of high-speed wireless LANs is a major goal of telecommunications industry. We propose a dual-frequency continuous wave (CW) radio holography method for evaluating radio wave propagation environments for such LANs. Our method images the propagation environment with higher resolution (1 ns or less) and higher sensitivity (10 dB μV/m) than conventional techniques which use frequency-modulated CWs (FMCWs), pseudonoise (PN) code-modulated waves, or pulse-modulated waves. A narrowband technique virtually eliminates the measurement inaccuracy caused by frequency response dispersion which is often a problem in conventional methods. This paper introduces the new radio wave propagation observation method by presenting examples of indoor propagation images and delay profiles observed at around 18 GHz