# Japanese 5G network and connectivity expansion > Live situation record from CLSTR: https://clstr.news/situations/japanese-5g-network-and-connectivity-expansion > Updated: 2026-10-13T04:00:00.000Z. Sources: 5. Developments: 2. Japanese telecommunications providers are advancing 5G infrastructure and connectivity technologies through various collaborative and specialized initiatives. Initially, four major mobile operators—SoftBank Corp, KDDI, NTT Docomo, and Rakuten Mobile—signed a memorandum of understanding to jointly explore methods for expanding 28GHz mmWave 5G coverage. This collaboration aims to address technical limitations such as signal attenuation and physical obstructions by studying compatible base stations, network architectures, and repeater equipment. Subsequently, NTT Docomo has focused on enhancing mobile communication environments across five major railway lines in the Kansai region. This involves expanding base stations and implementing ‘multi-user Massive MIMO’ technology to support high-speed 5G Sub6 connectivity. Furthermore, NTT Docomo and JR West are exploring the integration of AI and Non-Terrestrial Networks (NTN), such as satellites and High Altitude Platform Stations (HAPS), to improve railway safety, disaster response, and connectivity in mountainous or disaster-prone areas. ## Timeline ### 2026-10-13: NTT Docomo and JR West advance railway connectivity and safety technology NTT Docomo is upgrading 5G connectivity on major Kansai railway lines, while JR West and Docomo explore AI and satellite-based Non-Terrestrial Networks to improve railway safety and disaster resilience. 2 sources. https://clstr.news/cluster/ntt-docomo-and-jr-west-advance-railway-connectivity-and-safety-technology ### 2026-09-17: Japanese mobile operators collaborate to expand 5G mmWave coverage Japanese mobile operators SoftBank, KDDI, NTT Docomo, and Rakuten Mobile are collaborating to expand 5G mmWave coverage while competing for network speed and availability leadership. 3 sources. https://clstr.news/cluster/japanese-mobile-operators-collaborate-to-expand-5g-mmwave-coverage --- Cite as: Japanese 5G network and connectivity expansion. CLSTR, https://clstr.news/situations/japanese-5g-network-and-connectivity-expansion