IEEE 802.11b standard (also commonly referred to as 802.11 High Rate or Wi-Fi standard) is an extension to the original 802.11 wireless standard that was originally adapted by IEEE in 1997. It was in 1999 that IEEE ratified 802.11b extension to the original 802.11 wireless standard.

Just like the original IEEE 802.11 standard, IEEE 802.11b also applies to the wireless LANs, and also uses the 2.4GHz frequency band. Even though IEEE 802.11b provides for a maximum data transfer rate of 11 Mbps, it does allow for the data transmission rate to fallback to 5.5 Mbps, 2 Mbps, and 1 Mbps.

Unlike the original 802.11 standard that allows for the use of both the FHSS or DSSS encoding schemes, IEEE 802.11b makes use of only DSSS ( i.e. DSSS with CCK) encoding scheme.

802.11b products are also considered to be Wi-Fi Certified, and usually require fewer access points (APs) than 802.11a -especially when the coverage is needed for over large areas. Using 14 channels in the 2.4GHz frequency band (FCC regulations limit the use of only 11 in the U.S. though), 802.11b based devices routinely support sustained high-speed data transmission rates for up to 300 feet from the base stations.

It must be noted that the data transmission rates made possible with the use of 802.11b based devices allowed wireless data throughput to be quite comparable to the data transmission rates that were only previously possible over the wired (Ethernet) LANs.

Considering that 802.11b also used 2.4GHz band, the cost of migrating from the original 802.11 based devices to the new 802.11b based devices was not as high as the the cost of going from 2.4GHz (i.e. 802.11 based) devices to 5GHz frequency (i.e 802.11a based) systems. As a result, even though 802.11a standard was ratified way before IEEE had ratified the 802.11b standard, adaption of 802.11b standard was considerably wide-spread than that of the (supposedly faster) 802.11a standard.