As standards for Wireless LAN developed by IEEE, there are three types of standards including 802.11a, 802.11b, and 802.11g. While all of them use CSMA/CA, 802.11b provides the speed of 11Mbps and 802.11g provides max up to 54Mbps despite of relatively short distance. Since they both perform in 2.4 GHz area, they have compatibility in between.

802.11a operates in 5 GHz~6 GHz Wireless Frequency Area. Although 802.11a utilizes modulated system called OFDM in order to maximize the data transfer speed up to 54 Mbps, most of the time the actual communication is delivered in the speed of 6, 12, or 24Mbps.

Moreover, as wireless link velocity with the speed of 300Mbps, 802.11n Wireless LAN standard, recently developed up to Draft 3.0, provides a communication environment that is faster than that of Wired LAN. As a result, we expect the usage of Wireless LAN to be expanded.