Experimental analysis of multidimensional radio channels

In this thesis new systems for radio channel measurements including space and polarization dimensions are developed for studying the radio propagation in wideband mobile communication systems. Multidimensional channel characterization is required for building channel models for new systems capable of exploiting the spatial nature of the channel. It also gives insight into the dominant propagation mechanisms in complex radio environments, where their prediction is difficult, such as urban and indoor environments. The measurement systems are based on the HUT/IDC wideband radio channel sounder, which was extended to enable real-time multiple output channel measurements at practical mobile speeds at frequencies up to 18 GHz. Two dual-polarized antenna arrays were constructed for 2 GHz, having suitable properties for characterizing the 3-D spatial radio channel at both ends of a mobile communication link. These implementations and their performance analysis are presented. The usefulness of the developed measurement systems is demonstrated by performing channel measurements at 2 GHz and analyzing the experimental data. Spatial channels of both the mobile and base stations are analyzed, as well as the double-directional channel that fully characterizes the propagation between two antennas. It is shown through sample results that spatial domain channel measurements can be used to gain knowledge on the dominant propagation mechanisms or verify the current assumptions. Also new statistical information about scatterer distribution at the mobile station in urban environment is presented based on extensive real-time measurements. The developed techniques and collected experimental data form a good basis for further comparison with existing deterministic propagation models and development of new spatial channel models.reviewe

Examples Of Dynamic Wideband Mobile Radio Channel . . .

This paper presents examples of real-time wideband multichannel measurements of the radio channel of a moving mobile. The measurement method allows the investigation of the wideband dynamic mobile radio channel of adaptive antennas in realistic situations with normal mobile speeds. The number of recorded channels is at the moment 8, but it is being extended to 64 in the near future. This corresponds to e.g. 32 dual-polarized elements. The bandwidth can be up to 60 MHz. The channel characteristics that can be determined based on the data include amplitude, phase, excess delay, DOA and Doppler spectrum for each signal multipath component. Also the correlation between array elements and frequency correlation of the channel can be studied. The measured channels can be used for wave propagation studies and evaluation of different multichannel antenna and receiver configurations in different environments. Both mobile and base station ends of the channel can be measured due to the easily movable receiver