Wireless LANs are specified by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series standard. IEEE 802.11 series standard defines technologies and protocols for wireless LANs operating from 2 Mbps to 248 Mbps.
The Institute of Electrical and Electronics Engineers (IEEE), started development for a standard for WLANs that operate at a speed of 1 and 2 Mbps in 1990. Institute of Electrical and Electronics Engineers (IEEE) 802.11 WLAN standard was approved in 1997. Since the bandwidth of 2 Mbps was not sufficiant for new networks, a new IEEE 802.11b amendment was created and added 5.5 Mbps and 11 Mbps with a support of wireless devices that are up to 115 meters at 2.4 GHz frequency in 1999.
Institute of Electrical and Electronics Engineers (IEEE) proposed another standard 802.11a which specifies a maximum speed of 54 Mbps using the 5 GHz spectrum. The IEEE 802.11g standard was ratified in 2003 and can support devices transmitting at 54 Mbps.
802.11n is another amendment which improves the previous standards by adding multiple-input multiple-output antennas (MIMO) and other newer features. The IEEE has approved the 802.11n amendment and it was published in October 2009.
||The IEEE 802.11 WLAN standard (1997) was originally 1 Mbit/s and 2 Mbit/s, 2.4 GHz RF and infrared standard. 802.11 uses either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
||The IEEE 802.11a WLAN standard (1999, shipping products in 2001) is an extension to 802.11 which provides up to 54-Mbps in the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing encoding scheme.
|| The IEEE 802.11b WLAN standard (1999) is an extension to 802.11 that applies to wireless LANS and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1-Mbps) in the 2.4 GHz band. 802.11b standard allows wireless functionality comparable to Ethernet. 802.11b standard uses DSSS.
|| The IEEE 802.11g WLAN standard (2003) is an amendment to the IEEE 802.11 specification that extended throughput to up to 54 Mbit/s using the same 2.4 GHz band as 802.11b.
||The IEEE 802.11n WLAN standard (2009) is based upon previous 802.11 standards by adding multiple-input multiple-output (MIMO). The additional transmitter and receiver antennas allow for increased data throughput.
Beause of the nature of operation, the original IEEE 802.11 committee identified the possible threats of wireless networks and the members implemented several wireless security protections in the original 802.11 standard. These can be divided into three categories: controlling access, Wired Equivalent Privacy (WEP) encryption, and device authentication.