• Japan has become a hotbed of direct-to-cell satellite service activity with several deals inked between major Japanese telcos and global satellite specialists
• KDDI has hooked up with Elon Musk’s Starlink for its planned service
• The operator has just completed a successful trial that linked a standard smartphone using KDDI’s au mobile services to a Starlink satellite
• KDDI’s rivals are working with a variety of direct-to-cell satellite hopefuls

Japanese operator KDDI has taken a step closer to the launch of a commercial direct-to-cell satellite service following the successful completion of a trial with its partner Starlink, the low-earth orbit (LEO) operator that is part of Elon Musk’s SpaceX company.  

KDDI struck an agreement with SpaceX in September 2023 and has been working with Starlink since to develop an offering that provides connectivity services to users of au, the brand name for KDDI’s mobile service.  

Now KDDI says it has conducted a trial that confirmed that au smartphones can connect to Starlink satellites to send and receive SMS text messages even when they are out of reach of KDDI’s terrestrial mobile network or unable to connect (for any reason) to the KDDI network.

KDDI says the service, which will work with existing phones and internet of things (IoT) devices requiring without changes to hardware or software, will eventually offer voice calls and data services as well as SMS as Starlink’s LEO constellation capability is expanded.

Such a service has particular value and importance in Japan, given that it has many remote mountainous areas and small islands where it is hard to build out regular mobile network infrastructure. In addition, Japan is prone to unexpected severe weather as well as earthquakes (and resulting tsunamis) that can damage telecom networks and cut off regular cellular services. 

That in itself is no more problematic for Japan’s telcos today than it has been in the past, but actually restoring connectivity across hostile terrain in the 21st century when customers (both government and private business) are demanding ‘always-on connectivity’ for critical services and distributed computer applications, very much is. Uninterrupted service, rather than just fast restoration, is now the expected norm. Fortunately the Japanese technology ecosystem has long been at the forefront of installing and managing control systems to cope with weather-induced fluctuating water flows and the like throughout Asia.

The KDDI announcement made no mention of Musk himself, just SpaceX: Perhaps KDDI wants to ensure that its service strategy, rather than the notoriously flamboyant, publicity-loving Musk, got to bathe in the publicity spotlight. 

But Musk isn’t the only globally famous billionaire eying up Japan’s LEO satellite services sector, as the Tesla/SpaceX founder’s arch rival, Amazon chairman Jeff Bezos, is also in the frame courtesy of Amazon’s Project Kuiper. Its focus right now is on satellite broadband services but it is currently exploring ways in which it might also provide what it calls “direct-to-device” services. In the meantime, it has struck a deal with the Japanese telco giant NTT Group, including its mobile company NTT Docomo, for the provision of various satellite services across Japan – see Amazon lands LEO satellite deal with NTT Docomo.

Amazon is going for a big push to get about half of its planned 3,236 LEO constellation into orbit by late 2027. Having initially stunned the industry with its plan, Amazon has yet to launch any commercial ‘birds’ (the first are due in 2025), while boasting a “100% success rate” for its prototype satellite test mission. 

Meanwhile, Docomo is exploring other ways to provide an alternative to terrestrial mobile network coverage by exploring the potential of high altitude platform station (HAPS) services – see Japanese firms demo sky-high 5G.

SoftBank is also taking the HAPS route as part of its non-terrestrial network (NTN) plans, but its approach covers multiple bases. 

Three years ago, the Japanese multinational company introduced its own ‘concept’ of an NTN to “provide connectivity from space and the stratosphere”. The broader NTN plan includes collaboration with GEO satellite operator Skylo Technologies for narrowband IoT (NB-IoT) services and OneWeb for LEO-enabled data connectivity, but it also includes SoftBank’s own HAPS, a solar-powered “base station in the stratosphere” developed by its subsidiary HAPSMobile Inc. 

SoftBank has also struck a multi-year partnership with LEO operator Eutelsat/OneWeb to integrate OneWeb’s connectivity services into its offering for the Japanese market.

And then in September this year, SoftBank and US-headquartered Intelsat signed a “landmark collaboration” to build a single “ubiquitous network” to enable “seamless 5G connections” between terrestrial mobile networks and satellites so people (and things) can stay connected “anywhere in the world” with one device and one account – see SoftBank, Intelsat hatch ‘ubiquitous’ 5G plan.

Rakuten Mobile, meanwhile, has teamed up with AST SpaceMobile, which is focused on providing direct-to-cell services in partnership with multiple mobile operators around the world. The greenfield network operator’s parent company, Rakuten Group, has been an investor in AST SpaceMobile since 2020. Rakuten Mobile  announced earlier this year that it plans to launch a satellite-to-smartphone service in 2026 using AST SpaceMobile’s LEO satellites, the first of which were launched into orbit in September. 

– Ian Scales, Contributing Editor, TelecomTV