ITU's regulatory framework, technical studies in ITU-R, and future activities in relation to high-altitude-platform stations (HAPS)

As early as in 1996, the ITU-R Study Groups and the Radiocommunication Bureau [1–3], as well as the Radio Regulations Board in 1997 and the World Radiocommunication Conference 1997 (WRC-97), started considerations of a newly emerging technology: high-altitude-platform stations (HAPS), or stratospheric stations, as they were mainly called in the early studies. This article presents an overview of the developments during the study periods in ITU-R and the phases between WRCs, including the WRC process. In particular, it presents the radio-regulatory aspects as they are reflected in the ITU Radio Regulations and in Conference Resolutions. The various ITU-R Recommendations developed during the last and current study periods dealing with HAPS are also summarized. Since developments on HAPS and associated frequency-sharing studies are still going on, an overview of the current situation in preparation for agenda item 1.20 of WRC-12 (consider the results of ITU-R studies and spectrum identification for gateway links for HAPS in the range 5850–7075 MHz in order to support operations in the fixed and mobile services, in accordance with Resolution 734 (Rev.WRC-07)) is also provided.