DOUBLE DIRECTIONAL CLUSTER PROPERTIES INVESTIGATED FROM A SERIES OF ULTRA WIDEBAND PROPAGATION MEASUREMENTS IN HOME ENVIRONMENTS

The potential of multiple-input multiple output (MIMO) systems has been reported by many researchers. In MIMO systems, design of antenna systems is one of the important issues, because the channel capacity varies with the configuration of antenna arrays and antenna specifications such as directivities and polarizations [1]. Antenna design is also important in ultra wideband (UWB) systems, because transmission characteristics of UWB systems drastically varies by changing antenna orientations due to frequency-dependent antenna directivities. These facts yield demands for channel models which exclude antenna effects. To separate antenna effects from channel sounding results, the concept of the double directional channel has been developed [2]. In our study, we are focusing on the development of antenna-independent channel models by conducting a newly introduced double directional channel sounding, using a UWB signal to achieve fine temporal resolution. The UWB sounding enables a careful and accurate probing of physical phenomena and modeling of it, which are especially advantageous in indoor channel sounding and modeling. That kind of sounding is impossible to acheive in conventional wideband sounding. This report presents results from measurement of UWB double directional channels in a standard Japanese wooden house. Channel parameters which characterize behavior of channels were introduced. The paramaters help us not only interpret physical phenomena intuititively but also contribute to the antenna-independent channel models quantitatively.