Abstract: IBMS is a concept for future mobile communication systems to provide a large range of data rates with different degrees of mobility. The integration of heterogeneous services and communication systems requires a common Network Access and Connectivity CHannel (NACCH) for basic signaling to provide permanent network access. Smart Antennas are utilized to adaptively enable a trade-off between mobility and data rate. I.

| Ray tracing is a powerful method to determine the radio channel characteristics. Especially, for broadband transmission and to determine the angle of incidence, which is becoming more important with the introduction of directional antennas, ray tracing provides useful and realistic results. Two basic methods of ray tracing can be distinguished, the imaging method and the ray launching method. The latter one is preferable for large scenarios with many objects that are substance of reflection, transmission and diffraction. Ray launching owns the problems of detection gaps and double counts. To avoid these error sources a new twofold detection approach is introduced. Comparisons of the simulation results with reference values obtained by ray imaging show better agreement for the twofold method than for the common method. Furthermore, for validation of the simulation results broadband measurements have been performed and comparison with measurements show good agreements, too. I. INTRODU...

This paper describes novel 3-D radio channel measurements at the base station site in the urban environment. We introduce a new measurement concept which combines RF switching and synthetic aperture techniques and allows full 3-D characterisation of the channel. Additionally used dual-polarised patch antennas allow investigations both with vertical and horizontal polarisations. For estimation of the azimuth- and elevation angles of the incoming waves, we use high-resolution 2-D Unitary ESPRIT algorithm. We describe measurements with about 50 different transmitter positions and two receiver array sites with different antenna heights. Our results show that the environment seen by the base station strongly defines the propagation mechanisms. We demonstrate street canyon dominated propagation also when receiver array is at the rooftop level. We also show that signal components propagated over the rooftop are often related to the reflections from the high-rising buildings in the surroundings.