Challenges for 5G and Beyond

Abstract

In this paper, we discuss some challenges for 5G-and-beyond communications systems based on our measurements conducted with millimeter-wave (mmWave) channel sounders. One study analyzes path loss at 28 GHz vs. 83 GHz and in line-of-sight conditions vs. non-line-of-sight conditions and finds it to depend much more heavily on the latter than the former. A significant factor of path loss is penetration loss; in fact, another study focuses on obstructions that are typical in wireless environments: building walls, human bodies, and trees. Finally, in addition to investigating how power is distributed over distance through path loss, we also investigate how power is distributed over delay and angle per distance, otherwise referred to as channel dispersion. In particular, we discuss the importance of diffuse multipath to the total received power at mmWave and the foregone conclusion of wide-sense stationarity, which we show will often not apply to mmWave small-scale fading.