Experimental characterization of EHF multipath indoor radio channels

This paper reports on experimental results and their interpretations for an indoor extremely high frequency (EHF) multipath channel. It is intended to help in establishing design guidelines for indoor wireless communications systems using millimeter waves. It deals with measurements obtained for the narrow and wideband indoor radio channels at 37.2 GHz within a typical concrete building at Laval University. Two kinds of transmission antennas, omnidirectional and directional, are used to investigate the propagation characteristics for the indoor channel. Under line-of-sight (LOS) conditions, the distance-power law exponent is found to be lower than the free space condition with walls playing a major role on the sustaining of high level signals. Large- and smallscale variations extracted from the original data are shown to follow log-normal and Rice distributions, respectively. The observed wideband impulse response has delay spread extending over a range up to 40 ns and a maximum root mean square (rms) value of about 16 ns. Both amplitude and phase behaviors of the signals are available for a better understanding of the various effects.