Building Penetration Loss Measurements and Modeling from Cm-Wave to Sub-Terahertz Bands

As cellular networks move toward 6G, newly exploiting the centimeter wave (cm-wave) and sub-terahertz (THz) bands, the utilization of a combination of multiple frequency bands will be necessary for achieving extremely highspeed and reliable communications. However, the building penetration loss characteristics have not been sufficiently studied in terms of the frequency dependency from the cm-wave to sub-THz bands. We therefore investigated and modeled the building penetration loss characteristics and, as the measurement results indicated a more gradual frequency dependency than the conventional ITU-R model, we opted to build the penetration loss model based on single transmission paths with the lowest transmission loss through multi-layer standard glass. Our findings showed that the RMSE value with the proposed model was improved over the conventional ITU-R model for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$26.4-158~GHz$</tex> bands. We also confirmed the validity of the proposed model from the cm-wave to sub-THz bands.