The staggering growth in IP Traffic, the development of ICTs (Information And Communication Technologies) and IoT (Internet of Things) devices and connections have led to an increase in the demand for new applications, and the need for a ubiquitous, reliable, and scalable service worldwide. These requirements cannot be entirely fulfilled by the 5G TNs (Terrestrial Networks) due to two main inherent limitations: the intrinsic energy costs of such an architecture, and its deployment in remote regions. Meanwhile, in addition to the aforementioned needs, the increased commercial viability of HAPS (High Altitude Platform Systems), made possible by the advances in solar panel efficiency, antennas, composite materials, and cost of manufacturing and launching, has fueled the conceptualization process of the next generation of wireless communication systems (6G).