Standard 802.11 of the Institute of Electrical and Electronics Engineers (IEEE) has become the dominating solution for Wireless Local Area Networks (WLANs). Its simple and robust medium access protocol has paved the way for a mass market that is expected to ship one billion IEEE 802.11 devices in 2011. From the beginning of its standardization in 1990 until September 2011 twenty amendments have extended IEEE 802.11 for various applications. Examples are support for Quality of Service (QoS) that enables Voice over IP (VoIP) over WLAN and Consumer Electronic (CE) related applications, an extension for car to car communication that helps to enable new safety features, and intelligent radio resource management that targets new spectrum. These amendments make IEEE 802.11 a truly ubiquitous solution that is used in industrial machinery, point-to-point links, CE devices, computers, cars, mobile phones and many more products.