NTT docomo and Space Compass have successfully conducted a demonstration experiment of LTE data communication using a smartphone via HAPS, a high-altitude platform that flies in the stratosphere at an altitude of about 20 kilometers, in Laikipia County, Republic of Kenya.

In this experiment, radio waves sent from a ground-based LTE base station were transmitted to a smartphone on the ground via HAPS, which flies in the stratosphere at an altitude of about 20 kilometers.

Specifically, LTE base station installed on the ground was connected to a ground gateway station, and information and data were sent and received with a smartphone on the ground via a communication device equipped on HAPS that uses a relay technology that returns radio waves, called a non-regenerative relay method.

As a result, a throughput of over 4.66 megabits per second was confirmed in communication (forward link) from the ground gateway station to a smartphone relayed by HAPS. In addition, the team implemented technology that directs the center of the beam from the HAPS aircraft circling in the stratosphere to a fixed point on the ground to form communications coverage in a fixed area, and confirmed in a ground test area that the radio waves returned from HAPS could be received normally by a smartphone.
This is the world’s first successful establishment of wireless data communications with a smartphone on the ground using a small, fixed-wing HAPS aircraft flying in the stratosphere at an altitude of over 18 kilometers.

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