As communication technology extends from the ground to the sky and space, Japan's four major telecom operators—NTT, KDDI, SoftBank, and Rakuten Mobile—are accelerating the deployment of non-terrestrial networks (NTNs), aiming for commercialization between the second half of 2025 and 2026. The core driving force behind this "space race," besides addressing communication dead zones in mountainous areas and remote islands, is to cope with increasingly severe natural disasters, ensuring that even when ground base stations are damaged, communication islands can still operate via signals from the sky.
The following is a summary of the differences in the strategic layout and core technologies of the four companies:
NTT: Building an "Autonomous and Decentralized" Space Computing Network with IOWN Optical Technology
The core of NTT Group's strategy lies in technological independence and optical communications. Through its "IOWN" (Innovative Optical and Wireless Network) technology, NTT aims to transfer mature, high-speed, low-power optical chip technology from the ground to space, solving the problems of spectrum depletion and speed limitations in traditional radio waves.
NTT emphasizes infrastructure autonomy and plans to build a multi-layered network including stratospheric unmanned aerial vehicles (HAPS), low-Earth orbit (LEO) satellites, and geostationary orbit (GEO) satellites. The HAPS project, in collaboration with Space Compass and NTT DOCOMO, is expected to be commercialized in 2026, at which time it will be able to provide direct smartphone connectivity.
KDDI: Partnering with Starlink to pursue "real-time" and nationwide coverage
Compared to NTT's self-built approach, KDDI has adopted a more pragmatic cooperation strategy. Leveraging its deep alliance with SpaceX, KDDI utilizes the mature "Starlink" satellite system, emphasizing the immediacy and practicality of its services.
KDDI has already accumulated experience in earthquake relief and mountain hut communications in the Noto Peninsula of Japan. Starting in April 2025, KDDI will launch "au Starlink Direct," which utilizes a dedicated satellite operating at an altitude of 340 kilometers to allow commercially available smartphones to connect directly without modification. This will expand au's service coverage from just 60% of residential areas to the entire country of Japan, supporting emergency text messaging, message sending, and even generative AI applications.
SoftBank: HAPS, combining multiple orbital satellites, targets the "mobile Internet of Things"
SoftBank proposed the concept of "Ubiquitous Transformation," which adopts a hybrid strategy of HAPS and multiple satellite services running in parallel.
Regarding HAPS (High-Performance Online Services), SoftBank will launch pre-commercial services in 2026 using a balloon-shaped airframe from US company Sceye. A single airframe can cover a connection range with a diameter of 200 kilometers, suitable for disaster area reconstruction and drone communication. For the satellite portion, SoftBank is integrating Starlink Business with its exclusive Eutelsat OneWeb service. Leveraging OneWeb's low latency and high security features, SoftBank is aggressively targeting the "Mobility IoT" market, ensuring that connected vehicles, agricultural machinery, and construction equipment can maintain connectivity anywhere, paving the way for future autonomous driving and remote monitoring.
Rakuten Mobile: Giant antenna direct satellite connection, challenging 100% area coverage.
Rakuten Mobile is betting on a partnership with US company AST SpaceMobile, aiming to launch "Rakuten's most powerful satellite service" in the fourth quarter of 2026.
Its technological highlight lies in the fact that the AST commercial satellite "BlueBird Block 2" is equipped with a massive phased array antenna covering an area of 223 square meters (about the size of a standard tennis court), which can directly capture the weak signals of commercially available mobile phones, enabling communication without additional equipment. Furthermore, Rakuten Mobile emphasizes its leading role as an MNO (Mobile Network Operator), enabling it to independently manage ground gateways and flexibly allocate bandwidth to specific disaster areas during disasters, ensuring the quality of emergency communications.
Analysis of viewpoints
Looking at the strategies of Japan's four major telecom operators, although their ultimate goal is the same—to "eliminate those outside their designated areas" and strengthen their disaster response capabilities—their approaches are quite different. NTT takes a long-term strategy of in-depth technological development, KDDI emphasizes a pragmatic approach of rapid deployment, SoftBank focuses on industrial IoT applications, and Rakuten attempts to achieve ideal coverage without blind spots using giant antenna technology.
2026 will be a pivotal year for these technologies to converge. As these sky-based infrastructures gradually come into place, future "communication" will no longer be limited by terrain. This will bring revolutionary changes to disaster-prone Japan and even the global communication ecosystem.
