What is UNII-6?
UNII-6 is the second of the four sub-bands that make up the 6 GHz Wi-Fi band, and the smallest. It covers 6.425 to 6.525 GHz, just 100 MHz, with 20 MHz channels 97, 101, 105, 109 and 113. UNII stands for Unlicensed National Information Infrastructure, the FCC's name for these bands. Wi-Fi 6E and Wi-Fi 7 devices use it as part of the 6 GHz band.
The four 6 GHz sub-bands
| Sub-band | Frequency range | 20 MHz channels | US access point rules (FCC) |
|---|---|---|---|
| UNII-5 | 5.925 to 6.425 GHz | 1 to 93 | Low-power indoor, or standard power with AFC |
| UNII-6 | 6.425 to 6.525 GHz | 97 to 113 | Low-power indoor; no standard power |
| UNII-7 | 6.525 to 6.875 GHz | 117 to 181 | Low-power indoor, or standard power with AFC |
| UNII-8 | 6.875 to 7.125 GHz | 185 to 233 | Low-power indoor; no standard power |
Together the four sub-bands span 1,200 MHz, with 59 channels at 20 MHz. 6 GHz channel numbers start over at 1 and go up by 4. A channel's center frequency is 5.950 GHz plus 5 MHz times the channel number, so channel 97 is centered at 6.435 GHz.
US rules for UNII-6
In the United States (FCC), standard-power operation isn't allowed in UNII-6, so AFC (Automated Frequency Coordination) doesn't apply here. Access points use it as low-power indoor (LPI) devices: indoor-only units at limited power that can't be weatherproof or battery powered. The FCC kept standard power out because this sub-band carries mobile licensed services, such as TV broadcast links, that a location database can't protect.
There's no DFS in UNII-6 either. DFS is a 5 GHz rule.
Using UNII-6 in practice
At 100 MHz wide, UNII-6 holds five 20 MHz channels, two 40 MHz channels or one 80 MHz channel. Any 160 or 320 MHz channel that uses it also extends into UNII-5, UNII-7 or both. Channel 101 is the only Wi-Fi Alliance preferred scanning channel (PSC) in this sub-band. Many countries outside the US, including the European Union, opened only the 6 GHz spectrum below 6.425 GHz, so UNII-6 channels may not be available there.
For the CompTIA A+ exam
Core 1 (220-1201) objective 2.2 lists 6 GHz among the Wi-Fi frequencies and covers channel regulations. UNII-6 isn't named in the objectives. Know that the 6 GHz band is split into sub-bands with different rules, and that using 6 GHz takes a Wi-Fi 6E or Wi-Fi 7 device.