SoftBank boasts HAPS trial success, eyes launch in 2027

• Japan’s SoftBank Corp. has been testing services delivered by high-altitude platform station (HAPS) aircraft for years
• It ties in with the operator’s critical communications and 6G strategies
• It has completed a pre-commercialisation trial of various comms services to smartphones and drones with partner Sceye with a view to a full-scale launch next year
• The trial also included an airborne edge computing test that SoftBank believes will lead to the development of services that can support physical AI applications 

SoftBank Corp. has taken a step closer to the launch of communications services enabled by a high-altitude platform station (HAPS) ‘floating cell tower’ aircraft with a successful trial in Japan conducted in partnership with US aerospace specialist Sceye, paving the way for the launch of an initial commercial service in 2027. 

The Japanese operator has been researching the potential of HAPS platforms – uncrewed, solar-powered aircraft that can travel to and then remain in a certain area for an extended period of time – since 2017, and has long-regarded the technology as a key part of its 6G R&D. In 2021, it created a subsidiary called HAPSMobile (which has since been reintegrated into the main company) and acquired a set of patents from Loon, a helium balloon-based project shelved some years ago by Google’s parent company Alphabet. (For more on SoftBank Corp’s 6G preparations, read the latest free-to-download TelecomTV report, The AI-Native Path to 6G). 

Now it has successfully provisioned trial services to smartphones and drones in Japan from Sceye’s LTA (Lighter Than Air)-type HAPS aircraft, claiming that this “marks the first successful stratospheric-based communications test in Japan using a HAPS in Japan’s airspace.” 

The Sceye HAPS took off from Roswell, New Mexico, on 9 August, flew in the stratosphere (higher than commercial aircraft) more than 15,000km across the Pacific Ocean and reached Japan on 23 August to take up position “over a target area of operation off Cape Muroto in Kochi Prefecture for an extended [unspecified] period of time, where communications tests were conducted through SoftBank’s core network,” with the HAPS hovering within a 5km radius above the target service area, noted the operator in this announcement. 

Sceye HAPS flight route during the trial service: Source, SoftBank Corp.

For the trial, a 4G LTE-equivalent base station was installed on Sceye’s HAPS aircraft and hooked up to SoftBank’s core network platform via a ground gateway.

According to SoftBank, the HAPS was able to provide “stable” voice calls, (including emergency calls) and text messaging using smartphones, as well as high-capacity data communications, such as video streaming and video calls. The operator also “verified the operation of an emergency alert messaging system designed for use during large-scale disasters” (a scenario that is sadly front of mind currently following the disaster on the Nepal-Tibet border). 

In addition, SoftBank and Sceye “successfully validated HAPS-to-drone communications, working toward the realisation of a three-dimensional communications network”. The operator noted that “the use of HAPS is expected to enable a wide range of drone applications, including assessing damage and transporting supplies during disasters, monitoring remote islands and offshore areas, supporting logistics in mountainous regions, inspecting infrastructure, such as power transmission lines and roads, and monitoring forests.” 

SoftBank’s aim for the 6G era is to develop a “three-dimensional communications network by seamlessly integrating satellite, HAPS and terrestrial communications networks to provide stable connectivity not only on the ground but also to aerial mobility systems, such as drones. In the future, SoftBank will explore the use of technologies, including HAPS-based edge computing and AI-RAN, to expand HAPS use cases as part of next-generation communications infrastructure.”

The partners also conducted what they claim is “the world’s first technical verification of HAPS-enabled edge computing” that enabled communications from smartphones “to be processed entirely within the HAPS without being routed through a terrestrial network, with the results relayed back to smartphone”. 

SoftBank noted: “To explore the potential of edge computing in the stratosphere, a processing server was installed on the HAPS to conduct data processing directly on the platform. The tests showed that the average round-trip response time for processing on the server onboard the HAPS was 68 milliseconds, reducing communications latency by more than 40% compared with processing in the cloud via the internet. This marks the world’s first successful test in which a mobile core network and a web server for processing were installed on a HAPS, enabling response processing to be performed entirely onboard the HAPS and the results to be relayed back to smartphones. By combining the wide-area communications coverage provided by HAPS with edge computing technologies, SoftBank aims to enable new use cases that require both broad coverage and low latency, including applications in the field of physical AI and real-time video analytics.”

Overall, the trial “confirmed both the [HAPS] platform’s long-distance and long-duration flight capabilities and its ability to remain over a target area of operation for an extended period under conditions in Japan,” noted SoftBank, which added that the Sceye aircraft is currently en route back to New Mexico. 

Sceye has been working towards such a testing trial. In April this year, its HAPS successfully completed a 6,400 miles (10,300km) journey in the stratosphere from New Mexico to the coast of Brazil over the course of 12 days, which at that point was a record flight time. And in February, it unveiled SceyeCELL, which is described as “a first-of-its-kind, custom-built antenna… designed to bring high-speed connectivity at scale from the stratosphere. Described as a ‘cell tower in the sky, SceyeCELL merges the precision of satellite systems with the flexibility of cellular networks, enabling an entirely new category of telecom infrastructure built for wide-area coverage and long-duration operations.”

SoftBank isn’t the only Japanese operator exploring the potential of HAPS: NTT’s dedicated space unit, NTT C89, is also engaged in tests and trials, with Airbus subsidiary Aalto HAPS as its partner, though it has teamed up with other collaborators in the past.  

- Ray Le Maistre, Editorial Director, TelecomTV