SoftBank completed a high-altitude platform station trial service in Japan and said it expects to launch the HAPS service commercially in 2027.
The operator partnered with US aerospace company Sceye for the trial. Sceye sent the HAPS vehicle about 15,000 kilometers into the stratosphere during a pre-commercial flight from Roswell, New Mexico, to Japan.
Flight path, timing and operating area
The flight lasted 13 days and took place from August 3 to August 23. The trial flew over Muroto City in Kochi Prefecture and stayed within a 5-kilometer radius of the operational target area for an extended period.
Core network, base station and handset tests
SoftBank connected its core network to a 4G LTE-equivalent base station installed on the HAPS vehicle through a ground gateway. It also conducted two-way communication tests between the HAPS vehicle and smartphones on the ground.
SoftBank said the tests confirmed stable voice calls, text messaging, app use such as social media services, and high-capacity data communications including video calls and video streaming.
SoftBank and Sceye also verified emergency alert messaging for earthquake early warnings and tsunami warnings, as well as voice calls to Japan’s 118 maritime emergency number with the Japan Coast Guard.
Edge computing and drone trials
SoftBank is developing a next-generation three-dimensional communications network that integrates satellite, HAPS, and terrestrial communications networks. The company conducted automated drone flights to test the connection between HAPS and drones.
SoftBank installed a processing server on the HAPS platform to test edge computing in the stratosphere. SoftBank said the average round-trip response time for processing on the HAPS server was 68 milliseconds, reducing communications latency by more than 40% versus processing in the cloud via the internet.
Read for operators evaluating airborne edge architectures
The disclosed 68-millisecond round-trip time and the stated latency reduction give a concrete performance point for stratospheric processing on the HAPS server. SoftBank said it wants to use HAPS-wide area coverage and edge computing for use cases that need broad geographic reach and ultra-low latency, including physical AI systems and real-time video analytics.
SoftBank and Sceye plan to use the trial data to refine the operational framework and improve communication quality, with the aim of commercial launch by 2027. Junichi Miyakawa, SoftBank president and CEO, said the company will continue working with Sceye to integrate communications and AI technologies to develop HAPS into new social infrastructure.