What’s actually being tested (and where)
- Band & location: 7 GHz cm-wave, outdoor in central Tokyo (Ginza).
- Nodes: Three 7 GHz-compatible pre-commercial base stations co-located near existing 3.9 GHz 5G sites to enable like-for-like comparisons.
- Radio approach: Massive MIMO for contiguous area coverage.
- Timing: Trial license obtained; field work began June 2025; SoftBank announced on July 8, 2025.
Why 7 GHz matters
The upper 6 GHz/7 GHz range (≈ 6.425–7.125 GHz) is a leading 5G-Advanced/6G candidate because it can deliver much wider channels than today’s 3.3–4.2 GHz bands while preserving more practical cell sizes than mmWave. Light Reading frames potential capacity gains of 10–20× vs. 3.5 GHz with similar coverage (radio-planning dependent). That’s an operator-friendly trade-off if validated at scale.
Regulatory context varies by region: the GSMA forecasts growing IMT roadmaps for 6 GHz in 2025–2030, while in the U.S. the FCC recently expanded very-low-power unlicensed use across the entire 6 GHz band (5.925–7.125 GHz)—illustrating the ongoing policy split between licensed IMT and Wi-Fi proponents. Expect national decisions to shape ecosystem timing.
What SoftBank is trying to learn
SoftBank says the Tokyo trial compares coverage and radio characteristics of 7 GHz against nearby 3.9 GHz 5G, evaluating how 6G-class coverage could be engineered in dense urban areas using Massive MIMO. Co-location with existing rooftops helps isolate band-specific effects (path loss, penetration, interference). 
Business implications (early, but concrete)
- Capacity planning: If operators can stand up 80–200 MHz+ contiguous channels in 7 GHz with city-grade cell sizes, the band becomes a workhorse for mid-to-high-capacity macro/metro layers in 5G-A/6G—particularly where C-band is saturated.
- Device ecosystem: GSMA projects equipment scale-up aligned to national clearances in the 2025–2030 window. Early trials like SoftBank’s help de-risk RF front-end and antenna design (UE and FWA CPE).
- Policy stakes: Divergent national choices (licensed IMT vs. expanded unlicensed) will direct investment. Japan’s field work signals operator appetite for licensed IMT in upper-6/7 GHz
What to watch next
- Measured KPIs: Path loss, SINR maps, and throughput per PRB vs. 3.9 GHz across street canyons and indoors. (SoftBank has not yet released detailed results.)
- Uplink realism: UE antenna constraints at 7 GHz may cap UL; expect emphasis on TDD DL heavy splits, UL power control, and SRS-aided beam management. (Industry inference; confirm once data drops.)
- Interference management: Coexistence with fixed links and adjacent services; network-level inter-band handover strategies. (Regulatory studies ongoing across markets.)
- Ecosystem signals: Vendor roadmaps (RUs, RFICs, filters), and whether other APAC/EU operators replicate 3-site urban pilots this year.
