Stephan Häfner

Double-directional and dual-polarimetric indoor measurements at 70 GHz

Double-directional, ultra wideband dual-polarized channel measurements at 70 GHz have been carried out in a small-office environment. The aim of these measurements is to study the temporal, directional, and polarization properties of the channel for modelling purposes of the future wireless communication systems at mm-waves. A highly deterministic behaviour of the channel and the environment has been identified, as well as the limitations of only parameterizing channel models as WINNER for the new mm-wave channel models.

Ultra-Wideband Channel Sounder for Measurements at 70 GHz

Owing to the limitation in bandwidth of currently used frequency bands, future fifth generation (5G) mobile networks will need to operate at higher frequencies. However, one important step in the research activities for the next generation of mobile networks is the broadband fully polarimetric analysis of the multipath propagation in dynamic single and multiuser scenarios under time-variant shadowing environments in millimetre- wave (mm-wave) channels. This paper presents a channel sounding campaign at 70 GHz in an urban outdoor scenario focusing on broadband channel characteristic at mmwave. For the measurements a novel dual-polarized (DP) ultrawideband (UWB) multi-channel sounder (DP-UMCS) architecture, developed at the TU Ilmenau for propagation measurements in cellular networks, was used to study the directional and polarization properties of the channel in view of the future wireless communication systems.

Full 3D MIMO channel sounding and characterization in an urban macro cell

5G networks will target on smaller cells serving more and more mobile users. Especially on the base station side new technologies are needed circling as buzzwords like massive MIMO and elevation beamforming. In that context more precise channel models are required focusing on the elevation characteristic of the radio channel at the base station. In this paper an extensive channel sounding campaign in an urban macro cell using circular antenna arrays on both link ends is described and statistical analysis results are discussed based on the high resolution parameter estimation framework RIMAX.

Characterisation of Channel Measurements at 70GHz in Indoor Femtocells

A wideband, fully polarimetric and directional radio channel sounding campaign conducted at 70 GHz is presented. Measurement site was chosen as an entrance hall, featuring femtocell size. Transmitter and receiver were placed according to an access-point scenario. Initial large-scale parameters like excess-delay, delay-spread and angular spread are derived for channel characterisation. It is not the papers goal to describe a new channel model. The main focus is the identification of propagation effects and characteristics, which have to be considered in future modelling. It was found, that first more specular than diffuse components occur and second the channel is spatially sparse.