Spectrum Details for 5 GHz Frequency Band
| Band | 5 GHz |
| Band Name | 5 GHz U-NII-1 to U-NII-4 |
| Frequency | 5 GHz |
| Allocated Use | WLAN |
| Used in Region | Global |
| Used in Countries | United States |
| Duplex Mode | TDD |
| TDD Band (MHz) | 5150 - 58951 |
PART 15—RADIO FREQUENCY DEVICES
Technical Summary
Part 15 regulates unlicensed devices, such as Wi-Fi routers and Bluetooth transmitters, to prevent interference with licensed services. It includes technical standards for intentional and unintentional radiators, with power limits for devices in bands like 2.4 GHz and 5 GHz. Wi-Fi's output power is limited to 1 watt in certain U-NII bands. To ensure compliance, devices must undergo testing and meet specific emission thresholds.
Legal Details
Kama Thuo, PLLC Wireless Telecommunications Law Firm has compiled legal details on FCC Part 15.
| Name | Aliases | Freq. Range (GHz) | Bandwidth (MHz) | Max Power (mW) | Max EIRP (mW) |
|---|---|---|---|---|---|
| U-NII-1 | U-NII Low / U-NII Indoor | 5.150 –5.250 | 100 | 50 | 200 |
| U-NII-2A | U-NII Mid | 5.250 –5.350 | 100 | 250 | 1,000 (+DFS*) |
| U-NII-2B | 5.350 –5.470 | 120 | — | — | |
| U-NII-2C | U-NII Worldwide / U-NII-2-Extended / U-NII-2e | 5.470 –5.725 | 255 | 250 | 1,000 (+DFS*) |
| U-NII-3 | U-NII Upper | 5.725 –5.850 | 125 | 1,000 | 4,000 |
| U-NII-4 | 5.850 –5.895 | 45 | 1,000 | 4,000 | |
| U-NII-4 | DSRC/ITS/C-V2X** | 5.895 –5.925 | 30 | — | — |
*DFS (Dynamic Frequency Selection) is required by the FCC for U-NII 2A and 2C wireless communication devices to avoid interference with radar systems that operate in the same frequency bands (to protect incumbent users). DFS allows devices to detect radar signals and automatically switch to a different channel if radar activity is detected. See 47 CFR 15.407(h)(2).
**DSRC (Dedicated Short-Range Communications) or Celullar Vehicle-to-Everything (C-V2X) systems include road side units (RSUs) that require individual licenses under Part 90, Subpart M and on-bouard units (OBUs) (in-vehicle units) that are licensed-by rule under Part 95 (See 47 CFR Part 95 Subpart L).
| Band Portion | License Type | License Eligibility |
|---|---|---|
| 5150-5250 MHz (U-NII-1), 5725–5850 MHz (U-NII-3) | Unlicensed | Any Person or Entity |
| 5250–5350 MHz (U-NII-2A), 5470–5725 (U-NII-2C) | Unlicensed | Any Person or Entity |
For legal details on 5 GHz (or for counseling on spectrum licensing and allocation generally), see information at Kama Thuo, PLLC Wireless Telecommunications Law Firm.
Footnotes:
BW of 775 MHz for U-NII-1 to U-NII-4. U-NII-1=5.15-5.25 GHz; U-NII-2A=5.25-5.35 GHz; U-NII-2B=5.35-5.47 GHz; U-NII-2C=5.47-5.725 GHz; U-NII-3=5.725-5.85 GHz; U-NII-4 = 5.85 - 5.925 GHz (DSRC/ITS/C-V2X = 5.895-5.925 GHz).