Unlicensed National Information Infrastructure

The Unlicensed National Information Infrastructure (U-NII) radio band, as defined by the United States Federal Communications Commission, is part of the radio frequency spectrum used by WLAN devices and by many wireless ISPs.

As of March 2021, U-NII consists of eight ranges. U-NII 1 through 4 are for 5 GHz WLAN (802.11a and newer), and 5 through 8 are for 6 GHz WLAN (802.11ax) use. U-NII 2 is further divided into three subsections.

Wireless ISPs generally use 5.725–5.825 GHz.
In the USA licensed amateur radio operators are authorized 5.650–5.925 GHz by Part 97.303 of the FCC rules.

U-NII power limits are defined by the United States CFR Title 47 (Telecommunication), Part 15 - Radio Frequency Devices, Subpart E - Unlicensed National Information Infrastructure Devices, Paragraph 15.407 - General technical requirements.

Many other countries use similar bands for Wireless communication due to a shared IEEE standard. However, regulatory use in individual countries may differ.

The defunct European HiperLAN standard operates in same frequency band as the U-NII.

Except where noted, all information taken from Annex J of IEEE 802.11-2007 modified by amendments k, y and n. Because countries set their own regulations regarding specific uses and maximum power levels within these frequency ranges, it is recommended that local authorities are consulted as regulations may change at any time.

It operates over four ranges: