Propagation Characteristics of Indoor Radio Channel from 3.5 GHz to 28 GHz

In this paper, the channel propagation measurements have been performed in indoor scenario at 3.5, 6, 14, 23, 26 and 28 GHz. The measured cases include line-of- sight (LOS) and non-line-of-sight (NLOS) propagation. Statistical results and comparative analysis are presented in this paper, including path loss (PL) and root mean square (RMS) delay spread (DS). Both floating-intercept (FI) path loss model and alpha-beta- gamma (ABG) path loss model are provided. For the LOS propagation, path loss exponents at different bands are less than or closed to 2. PL exponents range from 2.7 to 4.2 in NLOS case. By fitting ABG PL model for each frequency band, the frequency dependent factors are observed as 2.21 and 2.33 in LOS and NLOS environments respectively. However, no tendency is found between the RMS DS and frequency in indoor scenarios. RMS DS seem not decreases with the increment of frequency bands. We also find that the RMS DS at any given location increases with separation distance and fluctuates seriously at larger distance.