COMPARATIVE-STUDY OF MILLIMETER-WAVE PROPAGATION AT 30 GHZ AND 60 GHZIN INDOOR ENVIRONMENT

The millimeter wave band appears to be a favourable choice for persona l wireless communication systems for indoor environment, as it meets t he requirements for sufficient bandwidth, small terminal dimensions an d sporadic usage for commercial applications. In. this paper measureme nts of millimeter wave propagation in both 30 GHz and 60 GHz bands, ar e presented in a comparative way. The topology of measurements covers both a line-of-sight situation and also a case where a direct path bet ween transmitter and receiver does not exist. Although the second case does not seem obvious for outdoor applications in these frequencies, in indoor environment the multipath signals produced by objects like w alls, doors, furniture etc., can be utilised in order to overcome the man-made shadowing, Both slow and fast fading characteristics of the r eceived signal are studied and the measurements are modelled by the co nventional Rician and Rayleigh distributions. Both frequency bands off er advantages for usage in in-house wireless communication systems Alt hough in 30 GHz band the coverage area is bigger than in 60 GHz (with the same transmitting power), frequency reuse is easier in 60 GHz band because even if millimeter waves 'escape' through 'windows', the spec ific attenuation due to atmospheric oxygen (15 dB/km) at 60 GHz elimin ates the interference between communication channels in neighbouring b uildings.