Investigations into the Effect of High-Ordering the Log-Distance Dependency of Path Loss Models for Indoor Wireless Channels

Abstract

The massively available amounts of bandwidth that exist in the frequency regime beyond 6 GHz together with the inability of the previous frequencies below 6 GHz have attracted the attention of the research and industrial communities to consider new frequency bands such as Super-High Frequency (SHF), millimeter-wave (mmWave), and further high-frequency bands such as the Terahertz (THz) bands to be the promising solutions to cope with the explosive demand of higher mobile data rate traffic. As a result, many research studies have reported the main wireless channel’s characteristics, such as the path loss over wide ranges of the SHF, mmWave, and THz frequency bands. However, most of the path loss modeling research has adopted the well-known close-in (CI) free space reference distance model to describe propagation effects of the wireless channel leaving behind the improvement concept. It is vital to estimate the path loss accurately since these high-frequency bands significantly suffer from the wireless propagation effects because of their tiny wavelength. This study presents investigations on high-ordering the dependency of the standard CI path loss model on the distance between the transmitting and the receiving antennas in the logarithmic scale. Two improved models are provided and discussed in this work: second-order CI and third-order CI models. The validation of the models’ accuracy is based on measurement data collected in a typical indoor corridor environment at 14, 18, and 22 GHz frequency bands. The main results show that the proposed two models outperform the standard CI model. Moreover, the results reveal notable reductions in the shadow fading’s standard deviation values as the model’s order increases. This means that more precision is provided. Finally, a trade-off study between the model’s accuracy and simplicity is provided in this paper.