SoftBank, Sceye Complete Japan's First Stratospheric Comm Trials

SoftBank Corp. and Sceye, Inc. completed Japan's inaugural stratospheric communications trials. Conducted off Cape Muroto in Kochi Prefecture, these tests verified stable voice, high-capacity data transfer, and emergency alert system functionality using a High Altitude Platform Station, or HAPS.

Credit: Softbank

The HAPS, an LTA type lighter than air platform, functions as a high-altitude base station. Residents in Shikoku reported observing a shiny, silver object aloft in late August, identified as this experimental HAPS. SoftBank research confirms this as Japan's first successful communications test between a HAPS and both smartphones and drones.

And the platform's journey to Japan was extensive. Sceye's LTA-type HAPS departed New Mexico, United States, in early August. It flew over 15,000 kilometres across the Pacific Ocean, maintaining stratospheric position. After approximately 13 days, it entered Japanese airspace in late August at 7:11 a.m., operating near Muroto City, Kochi Prefecture.

Sceye maintained the HAPS's position within a 5 kilometre radius, adjusting for stratospheric weather. This confirmed sustained operation over a target area. Following Japanese trials, the HAPS began its return journey across the Pacific Ocean to the United States.

Ground communication tests involved a 4G LTE-equivalent base station on Sceye's HAPS, connecting to SoftBank's core network via a ground gateway. Two-way communications with smartphones confirmed steady voice calls, text messaging, application use, and high-capacity data, including video calls and streaming.

But testing extended beyond standard mobile services. SoftBank and Sceye successfully trialled emergency alert messaging systems for earthquake and tsunami warnings. Voice calls to the 118 maritime emergency number were also made, collaborating with the Japan Coast Guard. Communications performance equivalent to terrestrial networks was reported, with reduced radio interference.

The initiative included developing a three-dimensional communications network. This aims to serve ground populations during disasters and offer connectivity to aerial mobility systems like drones. Communications tests between the HAPS and a drone were executed.

Automated drone flight was controlled remotely, utilising HAPS for connectivity. SoftBank confirmed stable drone flight control, reliable location information transmission, and consistent video transmission. HAPS is expected to support various drone applications including damage assessment, supply transport, remote monitoring, and infrastructure inspection.

So, a further world first was recorded with the technical verification of HAPS-based edge computing. A processing server was installed directly on the HAPS to handle data processing in the stratosphere. This addresses demand for lower-latency communications as artificial intelligence expands into areas such as Physical AI.

Tests revealed an average round-trip response time of 68 milliseconds for server processing onboard the HAPS, a latency reduction exceeding 40 per cent compared to cloud processing via the Internet. This trial marked the world's first instance where a mobile core network and a web server were deployed on a HAPS, enabling communication responses to be processed entirely onboard without terrestrial network routing.

SoftBank intends to use data and observations from these HAPS trial services to refine operational frameworks and enhance communication quality. The objective is to commercialise HAPS services in Japan from 2027. SoftBank plans a future three-dimensional communications network by integrating satellite, HAPS, and terrestrial networks for stable connectivity on the ground and for aerial mobility systems.

Junichi Miyakawa, SoftBank President and Chief Executive Officer, stated the successful trial represented an important step towards HAPS commercialisation. He added the organisation would continue to integrate various technologies, including communications and AI, to develop HAPS into a new form of social infrastructure.

• SoftBank and Sceye completed Japan's first stratospheric HAPS communication trials off Cape Muroto, Kochi Prefecture.

• The HAPS platform, originating in New Mexico, travelled over 15,000 kilometres to reach Japanese airspace for the tests.

• Trials verified stable voice, high-capacity data, emergency alert systems, HAPS-to-drone communication, and world-first HAPS-based edge computing.

• The edge computing achieved a 68-millisecond response time, reducing latency by over 40 per cent compared to cloud processing.

• SoftBank aims to commercialise HAPS services in Japan from 2027 and integrate them into a future three-dimensional network for 6G.

Source: SoftBank News