Mm-Wave Building Penetration Losses: A Measurement-Based Critical Analysis

The limited power-budget is known to be one of the main constraints in mm-wave radio links, especially when in-building applications are considered. In particular, outdoor-to-indoor and through-floor attenuation need to be analysed and carefully characterized at mm-waves in order to correctly approach both coverage and interference assessment issues. Surprisingly, only a few studies addressed the problem and no recommendation has been provided by standardization bodies so far for mm-wave through-floor attenuation in different building types. Therefore, a measurement campaign at 27 and 38 GHz was carried out to investigate the aforementioned issues. It is observed that in-building losses heavily depend on the building type, and that modern construction techniques make through-floor penetration almost impossible. This fact highlights the need for standard models for mm-wave through-floor propagation in different kinds of buildings.