High-Altitude Platform Stations as International Mobile Telecommunications Base Stations: A Primer on HIBS

Mobile communication via high-altitude platforms operating in the stratosphere is an idea that has been on the table for decades. In the past few years, however, with recent advances in technology and parallel progress in standardization and regulatory bodies like the 3rd Generation Partnership Project (3GPP) and International Telecommunications Union (ITU), these ideas have gained considerable momentum. In this article, we present a comprehensive overview of high-altitude platform stations (HAPS) as international mobile telecommunications (IMT) base stations (BS) (HIBS). We lay out possible use cases and summarize the current status of the development from a technological point of view as well as standardization in 3GPP and regarding spectrum aspects. We then present some system-level simulation results to shed light on the performance of HIBS. We conclude by pointing out several directions for future research.