Analysis Of Delay Characteristics At 4.9 Ghz And 28 Ghz In An Indoor Industrial Scenario

Abstract

The development of 5G promotes the interconnection of all things. And Industrial Internet of Things (IIoT) have attracted much attention because of its broad application value. In this paper, we present measurements that were conducted at 4.9 GHz and 28 GHz for comparing the channel delay spread in an indoor industrial scenario. Based on the measured data, the delay spread is compared at different frequencies. It can be found that the root mean square (RMS) delay spread (DS) is well fitted by a lognormal distribution. Besides, the mean RMS DS at 28 GHz is much smaller than that at 4.9 GHz. Compared with 3GPP standard, we find that the mean RMS DS in the indoor industrial scenario is much larger than that in the traditional indoor office scenario. At last, the effects of the TX-RX distance and antenna heights on RMS DS are investigated. By modeling DS as a function of the TX-RX distance, it is found that in the line-of-sight (LOS) scenario, RMS DS increases linearly with the TX-RX distance, both at 4.9 GHz and 28 GHz. By setting different antenna heights, it is found that in non-line-of-sight (NLOS), the mean RMS DS in the clutter-elevated scenario is 12 ns smaller than that in the clutter-embedded scenario. These results can provide insights into the design of IIoT systems.