Upper C-Band Reconfiguration and Allocation Plan
In GN Docket Nos. 25-59 and 18-122, the Federal Communications Commission adopted a Report and Order, Order of Proposed Modification, and Order on Reconsideration to make 160 megahertz of spectrum in the 3.98–4.14 GHz range available for terrestrial wireless flexible use across the contiguous United States (CONUS). This regulatory action fulfills and exceeds the mandate set by Congress in the One Big Beautiful Bill Act (OBBB Act), which directed the Commission to complete a competitive bidding system for at least 100 megahertz in the 3.98–4.2 GHz band by July 4, 2027.
Under the adopted band plan, the Commission added a primary non-Federal mobile (except aeronautical mobile) allocation to the 4.0–4.16 GHz band nationwide while removing the primary Fixed Satellite Service (FSS) allocation within CONUS. To prevent interference to repacked satellite operations remaining in the 4.16–4.20 GHz range, a 20-megahertz guard band is established at 4.14–4.16 GHz, replacing the prior 3.98–4.0 GHz guard band. Incumbent allocations and operations outside of CONUS remain unchanged.
- Reconfigures 3.98–4.14 GHz (160 MHz) for commercial terrestrial wireless operations.
- Establishes a 20-megahertz guard band at 4.14–4.16 GHz.
- Preserves 40 megahertz at 4.16–4.20 GHz for repacked primary FSS operations in CONUS.
- Maintains existing C-band FSS and Fixed Service allocations outside the contiguous United States.
Creation of Unified 3.7 GHz Service and Auction Framework
The Commission folded the Lower C-band (3.7–3.98 GHz) and the newly reconfigured Upper C-band (3.98–4.14 GHz) into a single, unified 3.7 GHz Service spanning 3.7–4.14 GHz in the contiguous United States. Licenses will be structured as eight unpaired 20-megahertz sub-blocks (designated Blocks C, D, and E) assigned on an exclusive Partial Economic Area (PEA) basis across 406 CONUS license areas.
The auction will follow the Commission's general Part 1 competitive bidding rules. The FCC adopted open eligibility standards without pre-auction spectrum aggregation limits, opting instead for post-auction case-by-case reviews and adding the 160 megahertz to the mobile spectrum screen. Designated entity bidding credits were established at 15% for qualifying small businesses (average gross revenues up to $55 million) and 25% for very small businesses (average gross revenues up to $20 million), along with a 15% bidding credit for eligible rural service providers.
- Licenses issued as unpaired 20-megahertz blocks on a PEA basis.
- 15-year initial license terms with standard Part 27 renewal requirements.
- Interim buildout requirement: 45% population coverage within one year of the relevant Transition Deadline.
- Final buildout requirement: 80% population coverage within five years of the relevant Transition Deadline.
- Failure to meet either benchmark results in automatic license termination for that license area.
Technical Rules and Radio Altimeter Coexistence Measures
To foster operational harmonization across the entire 3.7 GHz Service and ensure coexistence with aeronautical radio altimeters operating in the adjacent 4.2–4.4 GHz band, the Commission updated and aligned several Part 27 technical parameters. Fixed and base stations in non-rural areas are permitted power levels up to 1640 Watts/MHz EIRP, while rural base stations may operate up to 3280 Watts/MHz EIRP. Mobile and portable devices are permitted up to 4 Watts EIRP across the full 3.7–4.14 GHz band.
Responding to cross-industry consensus between wireless and aviation stakeholders, the FCC departed from its initial proposal and instituted a transmitting antenna height limit of 450 feet above ground level for base stations operating in 3.98–4.14 GHz. For out-of-band emissions into the 4.2–4.4 GHz band, base stations must comply with either a conducted power limit of -46 dBm/MHz or an EIRP limit of -28.4 dBm/MHz.
- Antenna height capped at 450 feet above ground level for 3.98–4.14 GHz operations.
- Out-of-band emissions into 4.2–4.4 GHz limited to -46 dBm/MHz conducted or -28.4 dBm/MHz EIRP.
- Power flux density (PFD) limit of -76 dBm/m2/MHz at service area boundaries at 1.5 meters height.
- Protection for incumbent FSS earth stations: PFD limit of -124 dBW/m2/MHz in 4.16–4.2 GHz and -16 dBW/m2/MHz blocking limit in 3.98–4.14 GHz.
- Protection for consolidated Telemetry, Tracking, and Command (TT&C) sites maintained until December 5, 2030.
FSS Transition Deadlines, Relocation, and Cost Reimbursement
Relying on its Emerging Technologies framework and Section 316 authority, the FCC ordered the clearing of incumbent FSS operations from 4.0–4.16 GHz in CONUS. The Commission set a Primary Transition Deadline of December 30, 2030, for clearing PEAs 1–41 and 43–76 (covering roughly 70% of the population), permitting wireless operations to commence on December 31, 2030. The Final Transition Deadline for all remaining CONUS PEAs is June 30, 2031.
New 3.7 GHz Service licensees must reimburse eligible space station operators (SES, Eutelsat, and Telesat) and incumbent earth station operators for reasonable and necessary transition costs. Earth station operators may choose actual cost reimbursement or elect an irrevocable lump sum payment per site within 45 days of the release of a Cost Catalog. An independent Upper C-band Clearinghouse and a Relocation Coordinator will oversee logistics, cost allocation, and claims processing.
- Primary Transition Deadline (Top 75 PEAs): December 30, 2030; wireless operations begin December 31, 2030.
- Final Transition Deadline (Remaining CONUS PEAs): June 30, 2031; wireless operations begin July 1, 2031.
- Eligible space station operators must submit initial Transition Plans by November 5, 2026.
- Soft costs are capped under a rebuttable presumption at 2% of hard costs.
- Reimbursement and rebate claims must be submitted no later than six months after the Final Transition Deadline.
Aviation Radio Altimeter Retrofit Rebates
To align the rollout of Upper C-band wireless networks with Federal Aviation Administration (FAA) retrofit standards, the Commission conditioned new flexible-use licenses on funding rebates for defined classes of aircraft operators and owners. This program supports compliance with FAA-mandated interference tolerance requirements for radio altimeters operating in the adjacent 4.2–4.4 GHz band.
Rebates will be administered by the Upper C-band Clearinghouse on a standardized schedule rather than through an actual-cost model. For the FAA's first retrofit deadline (December 30, 2030), eligibility is limited to U.S. Part 119 certificate holders operating Part 121 aircraft manufactured prior to January 1, 2030. For the second retrofit deadline (October 31, 2034), eligibility covers registered aircraft owners of Part 91 aircraft manufactured before July 1, 2031.
- Licensees fund pro rata shares of radio altimeter retrofit rebates based on gross auction bids.
- Rebates apply to installed radio altimeters on eligible pre-existing aircraft; spare inventories are excluded.
- Foreign-registered aircraft and equipment manufacturers are excluded from direct rebate eligibility.
- The Wireless Telecommunications Bureau will finalize rebate categories, dollar amounts, and procedures.