FCC Upper C-band Equipment Rules: 3.7–4.14 GHz Guide
FCC Upper C-band Equipment Rules: 3.7 GHz Service Grows to 4.14 GHz with Higher Device Power Limits
The FCC Upper C-band equipment rules came into force on 29 September 2026. In Order FCC 26-46, adopted on 22 July 2026 and published in the Federal Register on 31 July, the Federal Communications Commission opened 160 MHz between 3.98 and 4.14 GHz for terrestrial flexible use and folded it into a single 3.7 GHz Service covering 3.70–4.14 GHz. Most of the headlines are about the auction, but the order also changes the technical rules that radios in this band have to meet.
Background: from Lower to Upper C-band
The FCC cleared 3.70–3.98 GHz, the Lower C-band, for 5G in 2020, and those licences are now widely used. Congress then required the FCC to auction at least 100 MHz of the Upper C-band, with bidding completed by 4 July 2027. FCC 26-46 answers that requirement. It repurposes 3.98–4.14 GHz for terrestrial use, keeps a 20 MHz guard band at 4.14–4.16 GHz and confines remaining satellite operations to 4.16–4.2 GHz. The result is 440 MHz of contiguous mid-band spectrum. According to the FCC, winning bidders can start service in the top 75 markets in December 2030 and in the rest of the country from July 2031.
Key Changes in the FCC Upper C-band Equipment Rules
Higher power for mobile and portable devices
The power limit for mobile and portable stations rises from 1 W EIRP to 2 W EIRP, applied uniformly across 3.70–4.14 GHz. The FCC describes the change as incremental and mainly aimed at in-home fixed wireless devices.
Base station power and height
Fixed and base stations are capped at 1,640 W/MHz EIRP in non-rural areas and 3,280 W/MHz EIRP in rural areas, measured as the aggregate of all antenna elements in a sector. In 3.98–4.14 GHz, base station antennas are limited to 450 feet above ground level.
Out-of-band emissions and radio altimeters
Aircraft radio altimeters use 4.2–4.4 GHz, so the order keeps 60 MHz of separation from the new terrestrial band. Fixed and base stations must meet either −28.4 dBm/MHz EIRP or −46 dBm/MHz conducted for emissions into 4.2–4.4 GHz, and −13 dBm/MHz conducted elsewhere. Mobile and portable devices must keep conducted emissions at or below −13 dBm/MHz outside the authorized band, with narrower measurement bandwidths close to the channel edge.
Full-band interoperability
The FCC extended its interoperability rule in § 27.75 to cover 3.98–4.14 GHz. From 31 December 2030, new mobile and portable devices must be interoperable across the entire 3.70–4.14 GHz band. Lower C-band devices authorized before then that can't be upgraded may stay in service for their useful life. Equipment that already supports the full band can be authorized from the rules' effective date. The FCC didn't mandate any particular industry standard.
What This Means for Manufacturers
Chipset and module roadmaps should plan for 3.70–4.14 GHz support well before 31 December 2030, as new device certifications after that date will need it.
Devices such as fixed wireless routers can use the higher 2 W EIRP limit, which may change antenna, thermal and RF exposure design choices.
Test plans for C-band devices need to cover the wider band and the out-of-band limits, especially at the upper edge near the radio altimeter band.
RF exposure evaluations should reflect the higher permitted power where products use it.
Equipment certified only for 3.70–3.98 GHz stays legal, but it won't meet the 2030 requirement for new authorizations.
Base station and fixed equipment makers need to account for the new EIRP caps, emission options and height limit.
Certification Impact Summary
Area | Before | After | Impact level |
Band | 3.70–3.98 GHz | 3.70–4.14 GHz (guard band 4.14–4.16 GHz) | High |
Mobile and portable power | 1 W EIRP | 2 W EIRP across the band | Medium |
Emissions into 4.2–4.4 GHz | Lower C-band limits | −28.4 dBm/MHz EIRP or −46 dBm/MHz conducted for fixed and base stations | Medium |
Interoperability | § 27.75 covered the Lower C-band | Full 3.70–4.14 GHz for new mobile and portable devices from 31 December 2030 | High |
Base station height | No band-specific cap | 450 feet above ground in 3.98–4.14 GHz | Low |
Existing devices | Certified for 3.70–3.98 GHz | Can stay in service for their useful life | Low |
Timeline and Required Actions
Key Dates
Date | Milestone |
22 July 2026 | FCC adopts FCC 26-46 |
31 July 2026 | Order published in the Federal Register |
29 September 2026 | Rules take effect; full-band equipment can be authorized |
By 4 July 2027 | Upper C-band auction to be completed |
December 2030 | Service can start in the top 75 markets |
31 December 2030 | New mobile and portable devices must cover 3.70–4.14 GHz |
July 2031 | Service can start in remaining markets |
Required Actions for Manufacturers
Check which of your US 5G products, modules and chipsets support only 3.70–3.98 GHz.
Build 3.98–4.14 GHz support into product roadmaps for devices that will be certified near or after 2030.
Decide whether fixed wireless or portable designs will use the 2 W EIRP limit, and review RF exposure accordingly.
Add the new band edges and out-of-band limits to Part 27 test plans.
Track the FCC's later notice on the sections still awaiting OMB approval.
Plan certification of full-band devices ahead of operator launches in late 2030.
Conclusion
The FCC Upper C-band equipment rules turn an auction decision into a design requirement. Device makers have time, but the 31 December 2030 interoperability date and the higher power limit should shape product plans now. Contact our team for help with FCC Part 27 certification and test planning.
