Path loss models of millimeter-wave channel in indoor environment at 28 GHz

The millimeter-wave (mmWave) channel modeling will be one of the key technologies for the 5th generation (5G) mobile communication systems, and the path loss is a significant parameter which can be applicated to characterize the large scale fading of the mmWave channel propagation. To have a better understanding the propagation characteristics of mmWave channel, extensive channel measurements and modeling should be conducted. Thus, in this paper, the measurements of mmWave channel are carried out in indoor environment at 28 GHz, and the corresponding path loss models of mmWave channel are also given. At the same time, the propagation characteristics of path loss are analyzed based on the method of shooting-and-bouncing-ray/image (SBR/Image). The results show that:a good agreement is achieved between the measured results and the simulated results, so the correctness of SBR/Image method is validated; the path loss model of the close-in (CI) free space reference distance provides more accuracy and stability in indoor scenarios.Finally, a universally applicable path loss model for 28 GHz and 60 GHz mmWave channels in indoor LOS and NLOS environment is given.