FCC §15.407
FCC §15.407 is a section of Title 47 CFR Part 15 that regulates the operation of unlicensed intentional radiators—specifically wireless broadband devices—in the 5 GHz band. It defines technical requirements for transmission power, spectral characteristics, and dynamic spectrum access in the U-NII (Unlicensed National Information Infrastructure) sub-bands.
Scope and Application
This rule applies to:
Wi-Fi equipment using 802.11a/n/ac/ax in the 5.15–5.85 GHz range
Wireless access points, clients, and bridges
Devices operating in U-NII-1, U-NII-2A, U-NII-2C, and U-NII-3 bands
The rule enables high-throughput wireless networking under unlicensed conditions while ensuring protection of radar and licensed services.
Key Technical Requirements
Frequency Ranges and Sub-bands in the 5 GHz spectrum, each with distinct regulatory constraints. This classification is important for Wi-Fi device certification and deployment.
| Band | Details |
|---|---|
| U-NII-1 |
Frequency Range: 5.15–5.25 GHz Regulatory Notes: Indoor use only; outdoor APs allowed under conditions |
| U-NII-2A |
Frequency Range: 5.25–5.35 GHz Regulatory Notes: DFS and TPC required |
| U-NII-2C |
Frequency Range: 5.47–5.725 GHz Regulatory Notes: DFS and TPC required |
| U-NII-3 |
Frequency Range: 5.725–5.85 GHz Regulatory Notes: Outdoor use; higher power allowed |
| Band | Range (GHz) | Regulatory Notes |
|---|---|---|
| U-NII-1 | 5.15–5.25 | Indoor use only; outdoor APs allowed under conditions |
| U-NII-2A | 5.25–5.35 | DFS and TPC required |
| U-NII-2C | 5.47–5.725 | DFS and TPC required |
| U-NII-3 | 5.725–5.85 | Outdoor use; higher power allowed |
Output Power and Antenna Limits
U-NII-1 (indoor): Up to 50 mW conducted output power
→ Outdoor access points may be allowed up to 1 W, provided antenna gain does not exceed 6 dBi.U-NII-2A / 2C: Up to 250 mW conducted power
U-NII-3: Up to 1 W conducted power with antenna gain ≤ 6 dBi
→ If antenna gain exceeds 6 dBi, transmit power must be reduced by 1 dB for every 1 dB above 6 dBi.
DFS and TPC
DFS (Dynamic Frequency Selection): Required in U-NII-2A and U-NII-2C. Devices must vacate channels within 10 seconds after radar detection.
TPC (Transmit Power Control): Devices must reduce transmit power when full strength is not needed for reliable communication.
Emission and Bandwidth Rules
Spectral density: Max 17 dBm/MHz in U-NII-1/2/3
Out-of-band emissions: Must be ≤ −27 dBm/MHz at 75 MHz from band edges
Occupied bandwidth: Must match the declared channel bandwidth
→ For straddle channels that span two U-NII bands, devices must comply with the stricter limits of both adjacent bands.
Certification and Compliance
Devices operating under §15.407 require FCC Certification through a recognized Telecommunications Certification Body (TCB). Requirements include:
Conducted and radiated emissions testing
Radar detection simulations for DFS compliance
Power, bandwidth, and spectral mask verification through conducted measurements, if RF connectors are available
Need Help?
Support is available for FCC §15.407 certification, including DFS testing, TPC validation, and 5 GHz emission compliance. → FCC Certification & Market Access
Further Reading & Official Resources
Official FCC Rule Text (eCFR)
-
§ 15.407 – General technical requirements for the 5 GHz U-NII bands
This is a curated selection of key sources. For full and up-to-date regulatory documentation, please refer to the official portals of the relevant authorities. All references were verified as of April 2025.