high altitude platform system (HAPS)

Radio relay is realized by point-to-point connections or by point-to-multipoint connections. In order to extend the terrestrial limitations of directional radio, radio platforms stationed in the atmosphere are often used. High Altitude Platform Stations (HAPS) are such communication platforms, which are located approximately 20 km to 50 km above the earth. A HAPS platform has a fixed position with respect to the earth's position.

Such HAPS platforms are used as base stations for mobile networks. They can provide radio coverage for a larger rural area and can be used for both individual communications and broadcasting. They can also operate as relay stations for radio and microwave links.

HAPS can transmit and receive in a variety of frequency ranges. These include the microwave ranges at 2 GHz for mobile communications, the 28 GHz band, which is not globally released, however, and the 47 GHz band.