Wideband wave propagation measurements for local multipoint distribution services (LMDS) at 26 GHz

The results of a wideband measurement campaign at 26 GHz in the inner city of Karlsruhe, Germany, are presented. The measurements are performed using the Marconi (former Bosch Telecom) Digital Multipoint System (DMS). Therefore, the results can be directly adopted for planning purposes. The measurements are carried out for two different base station heights with several terminal station positions. Thus, a large number of different propagation scenarios is investigated, such as free Fresnel zone (FFZ), obstructed Fresnel zone (OFZ), obstructed line of sight (OLOS) and non-line of sight (NLOS) scenarios. In order to characterise polarisation effects both vertical and horizontal polarisation are utilised. Furthermore, the influence of vertical misalignment of the terminal station antenna is examined in NLOS scenarios. Using strong multipath components to build up stable links in NLOS scenarios is a critical issue in LMDS planning. Therefore, closer investigations on this issue are presented. As a last point the impact of vegetation obstructing the line of sight (LOS) path is analysed. For all scenarios the delay spread and coherence bandwidth are derived from the measured average power delay profile (PDP)