• Research into the potential of high-altitude platform stations (HAPS) for wireless connectivity has been underway for years
• It is regarded by a number of operators as a key way to enable total data communications coverage
• Now a consortium of Japanese companies, including NTT Docomo, has demonstrated 5G communications from an altitude of 4km

High-altitude platform stations (HAPS) have been in the R&D spotlight for a number of years already, with many high-profile (geddit?) efforts making headlines but ultimately going the same way as Icarus: Alphabet (Google)’s Loon project that tested wireless connectivity from helium balloons is one memorable example – see Loon falls back to earth with a bump.

But HAPS are regarded as an important part of 6G research, as well as ongoing efforts to find effective ways to provide connectivity in areas that cannot be reached by traditional communications networks – see How non-terrestrial networks can play a role in 6G.

Now comes news that a consortium of companies in Japan, comprising giant mobile operator NTT Docomo, satellite operator Sky Perfect JSAT, the National Institute of Information and Communications Technology (NICT) and Panasonic Holdings, has successfully conducted a 5G communication verification test from an altitude of approximately 4km using spectrum in the 38GHz band, standard 5G technology deployed in a small Cessna aircraft operated by Kyoritsu Air Survey and a “lens-type antenna with an auto-tracking function” as the ground station. 

According to NTT Docomo, the demonstration, which “established an aerial relay backhaul line between the Cessna aircraft, flying at altitude of approximately 4km, and three ground stations…  was the first of its kind in the world.” 

Docomo added: “With 5G evolution underway and 6G implementation on the horizon, various efforts are being made to expand coverage areas. Non-terrestrial networks (NTNs) using HAPS is a promising technology for such expansions, so the results from this demonstration will help accelerate the practical application of HAPS networks.”

NTT Docomo isn’t the only Japanese operator exploring the potential of HAPS: SoftBank has been researching the potential of HAPS platforms since 2017, and regards the technology as a key part of its 6G R&D: In 2021, it created a subsidiary called HAPSMobile and acquired a set of patents from… Loon!

And all of the Japanese operators, as well as many other telcos around the world, are teaming up with (and in some cases investing in) low-earth orbit (LEO) satellite operators, such as OneWeb, Starlink, AST SpaceMobile and Project Kuiper, as part of their NTN strategies – see Why LEO satellite players are telcos’ new best friends.

- Ray Le Maistre, Editorial Director, TelecomTV