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Tokyo’s Marunouchi District to Become Next-Generation Smart City With Advanced 5G Infrastructure
28 Aug 2026
NTT Docomo and Mitsubishi Estate are developing a next-generation smart city across Otemachi, Marunouchi and Yurakucho, using advanced 5G, millimetre-wave connectivity and existing urban infrastructure to create a more connected business district.
Tokyo, Japan — August 2026 — NTT Docomo and Mitsubishi Estate have agreed to develop a next-generation smart city across Tokyo’s Otemachi, Marunouchi and Yurakucho districts, one of Japan’s most important office and commercial centres.
The project will combine advanced telecommunications infrastructure with Mitsubishi Estate’s urban development assets, aiming to improve connectivity across an area where large numbers of workers, businesses and visitors generate significant daily data traffic.
Advanced 5G at the Centre of the Project
The new smart-city infrastructure will use high-capacity 5G technologies, including 26GHz millimetre-wave spectrum, alongside existing 28GHz capacity.
NTT Docomo also plans to use technologies including Tri-Band Massive MIMO, glass antennas and its latest base-station equipment.
The challenge is not simply increasing network capacity. Millimetre-wave signals can deliver high speeds but have shorter ranges and are more easily blocked by buildings and other obstacles.
As a result, the partners will test antenna placement designed to improve coverage while preserving the appearance of the historic Marunouchi streetscape.
Turning the Entire District Into a Connected Platform
The project forms part of Mitsubishi Estate’s Whole Town Workplace concept.
Rather than treating individual buildings as separate spaces, the strategy views the wider Marunouchi area as one connected platform through which businesses, employees and visitors can access shared infrastructure and digital services.
The ambition is to support services that individual office tenants might struggle to deploy independently, while strengthening Marunouchi’s competitiveness as an international business district.
Existing Urban Infrastructure Will Be Reused
NTT Docomo and Mitsubishi Estate also plan to make greater use of infrastructure already available across the district.
This could include installing communications equipment within office and commercial buildings while using existing data centres and fibre-optic networks operated by Mitsubishi Estate group companies.
The approach could allow new connectivity infrastructure to be deployed more quickly and with less disruption than building entirely new systems.
A Model for Other Japanese Cities
The companies intend to use Marunouchi as a model for future deployments.
Once the urban antenna designs and infrastructure-sharing approach have been established, similar clusters could be introduced in other major Japanese city centres.
The partners are also considering future use of All-Photonics Network (APN) technology, which transmits information optically to support higher capacity, lower latency and lower energy consumption.
Connectivity as Urban Infrastructure
The Tokyo initiative reflects a broader change in smart-city development.
High-speed connectivity is increasingly being treated in the same way as transport, energy and other core urban infrastructure. Technologies such as AI, digital twins, connected mobility and real-time city services all depend on reliable underlying networks.
For Marunouchi, the project is therefore about more than faster mobile connections. It is an attempt to create a digital foundation capable of supporting future services across an entire urban district.
If successful, the model could offer other dense city centres a way to upgrade digital infrastructure without separating connectivity planning from the physical design of the city.
Sources
- NTT Docomo and Mitsubishi Estate announcement,
- SmartCitiesWorld — “Next-gen smart city to be developed in Tokyo”,
- SmartCitiesWorld Weekly Newsletter,
