Japan Four Big Telcos Form 5G Millimeter-Wave Sharing Pact
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Japan’s four nationwide mobile operators signed an agreement on September 21 to jointly study sharing 28GHz millimeter-wave 5G base stations and network architectures.
The pact brings together KDDI, NTT Docomo, SoftBank and Rakuten Mobile. Together, their networks serve more than 200 million cellular subscriptions.
Sharing high-band physical infrastructure
Signals at 28GHz deliver ultra-high speeds and heavy throughput. However, the radio waves travel short distances and cannot penetrate concrete walls, glass or foliage. Covering a single commercial district requires hundreds of small cells and repeaters. That multiplies site acquisition costs and power bills for each carrier.
Under the memorandum of understanding, the four operators will examine technical frameworks to share base station equipment, repeaters and related transmission assets. Each carrier will continue independent commercial rollouts. A joint working group will test how traffic from rival subscriber bases can run across shared physical nodes without degrading data security or individual network performance.
The cost math behind 28GHz networks
High-frequency spectrum rollouts have stalled worldwide because capital expenditure per square kilometer outpaces consumer revenue gains. Worldwide mmWave 5G spending is projected to climb from 3.84 billion dollars in 2025 to 4.42 billion dollars in 2026. Even so, individual operators face severe balance-sheet pressure when building proprietary high-band grids.
“Enterprise fixed wireless access deployments then expanded into industrial parks and logistics hubs through 2024 and 2025.”
By sharing cell sites and repeaters in dense retail quarters, transit hubs and stadiums, Japanese operators aim to cut duplicate capital outlays. Mall operators, transport hubs and enterprise landlords also gain. A unified model eliminates the need to host four separate sets of antennas and power feeds on roofs and interior walls.
Shifting carrier spending to shared utilities
This alliance shifts carrier dynamics across Japan. Rather than competing purely on antenna counts, the operators are treating high-frequency physical layer equipment as a common utility. Core networks and retail pricing plans will remain distinct.
Operational risk sits in maintenance allocation and capacity bottlenecks during localized peak events. If one carrier’s subscribers crowd a shared node during an urban festival or sporting fixture, the system must arbitrate spectrum access without triggering regulatory complaints over fair competition.
Earlier trials and global deployment lines
Collaborative network trials have gained ground across international markets as carriers confront sub-6GHz spectrum exhaustion. Global equipment vendors and tier-one operators launched initial commercial mmWave clusters in early 2023. Enterprise fixed wireless access deployments then expanded into industrial parks and logistics hubs through 2024 and 2025.
Japanese carriers previously tested private 5G and standalone 28GHz cells in manufacturing facilities and isolated transit pilots. Despite those trials, commercial handset connections rarely lock onto millimeter-wave signals outside select train platforms and flagship retail venues.
Technical evaluations under the new memorandum will run over the coming quarters. Teams will focus on multi-operator core network integration and shared repeater specifications ahead of targeted commercial joint-site deployments.
Questions & Answers
Q.Which specific technical aspects will the four Japanese mobile operators study together under this new agreement?
Which specific technical aspects will the four Japanese mobile operators study together under this new agreement?
The four operators will jointly study sharing 28GHz millimeter-wave 5G base stations and network architectures. They will examine technical frameworks for sharing base station equipment, repeaters, and related transmission assets, and test how rival subscriber traffic runs across shared physical nodes.
Q.What are the main financial and logistical benefits operators hope to achieve by sharing millimeter-wave infrastructure?
What are the main financial and logistical benefits operators hope to achieve by sharing millimeter-wave infrastructure?
Operators aim to cut duplicate capital outlays by sharing cell sites and repeaters in dense areas like retail quarters and stadiums. This reduces site acquisition costs and power bills, lessening balance-sheet pressure from proprietary high-band grid construction.
Q.How will this agreement affect the commercial competition and individual service offerings of the participating carriers?
How will this agreement affect the commercial competition and individual service offerings of the participating carriers?
Each carrier will continue independent commercial rollouts, and their core networks and retail pricing plans will remain distinct. The alliance treats high-frequency physical layer equipment as a common utility, but competition on services remains.
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