6 IEEE 802.11 Legacy (Wireless LAN)

IEEE 802.11 can, in simple words, be described as the standard for “wireless Ethernet”.

The original standard of IEEE 802.11 that was released in 1997 specifies Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) as the media access method, just like Ethernet does. All amendments to IEEE 802.11 are based on the same access method. However, CSMA/CA is a very inefficient access method since large amount of the bandwidth is sacrificed to ensure a reliable data transmission. This limitation is inherent to all CSMA/CA based technologies.

Furthermore, IEEE 802.11 specifies two basic data rates, 1 and 2 Mbps to be transmitted via Infrared (IR) or 2.4GHZ. Although there is no implementations based on IR, it still remains as a part of the original standard.

A handful of commercial products appeared on the market using the original specification of IEEE 802.11 but was soon to be replaced by the IEEE 802.11b products when the “b amendment” to the original standard was ratified in 1999.

IEEE 802.11 is known by many names such as Wi-Fi, Wireless-Fidelity, WLAN, Wireless LAN and IEEE 802.11x. Let us try to sort out this confusion regarding the name before we move on to different amendments (versions) of the IEEE 802.11 standard.

• Wi-Fi is a “brand”, that is licensed by the Wi-Fi Alliance for products that meet the requirements for interoperability among products based on the IEEE 802.11 standard. In other words, a Wi-Fi network is a network meeting the standard IEEE 802.11. The name “Wi-Fi” is nowadays commonly used instead of “IEEE 802.11” in the same way as Ethernet is being used for “IEEE 802.3”. Despite what most Wi-Fi users believe, Wi-Fi is NOT an abbreviation of “Wireless Fidelity”. It was once used by the Wi-Fi Alliance when the marketing the certificate with the tag line, "The Standard for Wireless Fidelity," but later removed from their marketing¹⁾.

• Wireless LAN or WLAN is commonly used as a name for any wireless local area network that uses radio waves as carrier. Wireless LAN is also the alternative name of the IEEE 802.11 standard used by IEEE.

• IEEE 802.11x is sometimes used to refer to the whole group of standards within IEEE 802.11 (b, a, g etc.). The same name is also used to refer to a group of evolving standards within the IEEE 802.11 family that are under development but that have not yet been formally approved or deployed. And, the name also is often mistaken with the IEEE 802.1x standards for port-based network access control. However, there is no standard or task group named "802.11x". To avoid confusion, we strongly suggest you to be careful when using the term IEEE 802.11x.