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Definition: 802.11 versions


Following is a summary of the IEEE 802.11 Wi-Fi standards, from newest to oldest. If devices with different versions communicate, the transmission will be at the highest common speed between them.

The Wi-Fi Alliance began a new branding with 802.11ax. Called "Wi-Fi 6," previous versions retroactively became 1 to 5. See 802.11 and Wi-Fi.

11ax (2021) - Highest Speed (Wi-Fi 6)
802.11ax, branded as "Wi-Fi 6," operates in the 2.4 GHz and 5 GHz bands with data rates in the multi-gigabit range. More multiuser modes support higher user density. Wi-Fi 6E (Extended) adds the 6 Ghz band. See Wi-Fi 6.

11ac (2012) - High Speed (Wi-Fi 5)
802.11ac operates in the 5 GHz band with data rates into the gigabit range (see 802.11ac). Very valuable when multiple users are online at the same time.

11n (2009) - High Speed (Wi-Fi 4)
802.11n uses multiple antennas for speeds up to 450 Mbps. 11n operates in both 2.4 GHz and 5 GHz spectrum bands and is compatible with previous 11b/g and 11a standards (see 802.11n). More than enough speed for the casual user.

11g (2003) - Medium Speed (Wi-Fi 3)
Using orthogonal FDM (OFDM) transmission, 802.11g increased speed in the 2.4 GHz band to 54 Mbps. Both 11b and 11g are compatible, and equipment is often designated as 802.11b/g. See OFDM.

11a (1999) - Medium Speed (Wi-Fi 2)
Using orthogonal FDM (OFDM), 802.11a transmits up to 54 Mbps. It uses the 5 GHz band and is not compatible with 11b.

11b (1999) - Slow Speed (Wi-Fi 1)
Using DSSS and the 2.4 GHz band, 802.11b boosted speed to 11 Mbps while retaining the slower DSSS modes to accommodate weak signals. It was the first major wireless local network standard, and many laptops were retrofitted with 11b network adapters. Later, 11b was built into the laptop motherboard.

Original Spec (1997)
The original 802.11 specification included two spread spectrum methods in the unlicensed 2.4 GHz band: 1 Mbps frequency hopping (FHSS) and 1 and 2 Mbps direct sequence (DSSS). It also included an infrared method. Both FHSS and infrared were dropped by the Wi-Fi Alliance, but 1 Mbps DSSS method is still used by access points to advertise themselves (see beaconing).