Measurement and Evaluation of 28 GHz Propagation Characteristics in Specific Environments

New specific scenarios are expected for 5G systems in various environments, such as stadiums, subway platforms, factories, livestock barns. On the other hand, the applicability of conventional propagation models to new specific environments has not been clarified. In this paper, we report path loss and spatiotemporal characteristics such as delay spread (DS) and azimuth and zenith angular spread of arrival (ASA and ZSA) in the 28 GHz-band in various environments. By comparing the degree of fit to the conventional models, we considered whether the models for conventional scenarios assumed by previous mobile systems can be applied to the propagation characteristics in each specific environment. As a result, we clarify that the following points should be considered when applying the conventional model. The measured path loss characteristics were mostly close to those of the conventional models. However, the path loss in the non-line-of-sight with propagation to another room was larger than the conventional model, assuming there was a hall space environment with some blockers. Regarding the DS, we obtained the results that the characteristics were mainly affected by existence of long-distance delayed wave caused by a long narrow space and materials of the internal walls and ceiling. Larger ASA characteristics were obtained in the subway platform environment and the factory environment because of metallic obstacles and walls. Regarding the ZSA, a larger ZSA was obtained in the stadium due to scattering from spectator seats, and a smaller ZSA was obtained in the subway platform due to the low ceiling height and long propagation distance.