  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 3GPP and ITU, these ideas have
gained considerable momentum. In this article, we present a comprehensive
overview of HIBS - High Altitude Platform Stations as IMT Base Stations. We lay
out possible use cases and summarize the current status of the development,
from a technological point of view as well as from standardization in 3GPP, and
regarding spectrum aspects. We then present preliminary system level simulation
results to shed light on the performance of HIBS. We conclude with pointing out
several directions for future research.
