SoftBank Restores Mobile Coverage Across 5Km Radius from 3,000 Metres

SoftBank Corp. Announced this week the successful completion of a trial providing mobile communication capability from the air to establish temporary ground coverage during large-scale disasters.

The trial utilized a domestically designed and manufactured Disaster Relief Unit Pod mounted on a large remotely piloted aircraft system operated by the Japan Coast Guard, conducted in collaboration with the Ministry of Internal Affairs and Communications.

Airborne Cells Over Disaster Zones

Transmitting radio waves from an altitude of 3,000 meters, the aircraft established a mobile communication area with a radius of over 5 km, delivering outdoor download speeds of up to 20 Mbps and upload speeds of up to 5 Mbps on 5 MHz bandwidth.

Japan’s Ministry of Internal Affairs and Communications conducted the test alongside the Coast Guard in an inter-ministerial partnership. State backing reflects urgent policy pressure to harden communication networks against catastrophic seismic events along the Nankai Trough.

Commercial Stakes for Asian Operators

Regional carriers across Asia-Pacific face heavy costs from climate-driven network outages, yet few have solved wide-area restoration beyond truck-mounted base stations that stall at flooded or blocked roads. Telcos in the Philippines, Indonesia, and Taiwan have tested tethered drones and satellite-to-cell protocols. Short battery endurance and low data throughput limit those tools. SoftBank’s use of a long-endurance maritime surveillance drone bridges the gap between low-capacity orbital links and localized field generators.

Fleet costs for dedicated aircraft remain steep. Telecom operators cannot justify buying military-grade drones solely for disaster standby. Shared-asset pacts with coast guards and civil defense agencies offer the only workable operating model. SoftBank is positioning its communications pod as a plug-and-play government utility rather than a standalone carrier capital expenditure.

From Coastal Helicopters to Fixed-Wing Drones

Testing builds on a phased development program. SoftBank ran initial flights in March 2026 by mounting the DRU Pod on a conventional helicopter over Kuroshio Town in Kochi Prefecture. Those trials proved signal transmission geometry. Engineers then adapted the housing for high-altitude, long-endurance fixed-wing drones capable of staying airborne for dozens of hours.

Funding stems from a research contract titled Development of Aerial Mobile Network Systems for Rapid Coverage Restoration in Disaster-Affected Areas, awarded to SoftBank in 2023 under the Beyond 5G and 6G Fund Program run by Japan’s National Institute of Information and Communications Technology.

Next Steps in Fleet Integration

SoftBank will now refine pod aerodynamics and automate spectrum handoffs between aerial platforms and surviving ground towers. Field teams plan to test autonomous deployment routines to cut launch preparation times following emergency alerts. Regulators and emergency planners will evaluate standardized operational protocols for the system ahead of commercial rollout targets for coastal disaster response units.