802.11n is a specification for wireless LAN (WLAN) communications. 802.11n, an addition to the 802.11 family of standards, will increase wireless local area network(WLAN) speed, improve reliability and extend the range of wireless transmissions.
802.11n uses multiple input / multiple output (MIMO) technology and a wider radio frequency channel. It also provides a mechanism called frame aggregation to decrease time between transmissions. Current WLAN technologies require that the sending station request the channel, send one packet, release the channel, and then request again in order to send the next packet. With frame aggregation, once a station requests the channel and has the authority to transmit, it can transmit a series of frames without having to release the channel and regain authority for each frame. With 802.11n, raw data throughput is expected to reach as much as 600 Mbps -- that's more than 10 times the throughput of 802.11g.
Although the IEEE began work on 802.11n in 2004, progress in ratifying the specification was stalled by competing vendor groups. Draft 1 of the standard was released in 2006 and "pre-N" equipment became available shortly after. Draft 2 was approved in 2007. Pre-N equipment has demonstrated a data rate as high as 540 Mbps with typical rates between 100 and 200 Mbps. Data rates are expected to increase as experience with the standard grows.
See also: single stream 802.11n
Lisa Phifer explains how 802.11n antennas work in Understanding 802.11n wireless antennas.
To learn more about the 802.11 family, see our 802.11 Fast Reference