The developing IEEE standard (estimated March 2009) for an 802.11 wireless local area network (WLAN) operating in the 2.4-GHz band and operating at a signaling speed of up to 108 Mbps, with an option to increase speed to as much as 600 Mbps. 802.11n will be backward-compatible with 802.11a/b/g, building on them by introducing antenna technology known as multiple-input multipleoutput (MIMO), which is based on the concept of spatial diversity.The transmitter splits the signal among multiple transmit antennas separated by some amount of space, but operating on the same frequency at the same time. The multiple receive antennas gather the signal, which has suffered from the effects of multipath propagation. Some signal elements will be stronger than others and will arrive ahead of others. Sophisticated signal processing software combines and correlates many signal elements arriving at different times into one linear combination of a stronger, synchronized, intelligible signal derived from each of the receive antennas and reconstitutes the original data stream. See also 802.11a, 802.11b, 802.11g, IEEE, frequency, MIMO, multipath propagation, and spatial diversity.
An IEEE 802.11 Wi-Fi standard that increases transmission speeds to 600 Mbps and works in both the 2.4 GHz and 5 GHz frequency bands (see dual-band router). Although newer 802.11ac devices began to proliferate in 2013, 802.11n is expected to exist for some time because 11n speed is more than adequate for most purposes when only one or two users are transmitting at the same time. Multiple Antennas (MIMO) The 802.11n technology brought the use of multiple antennas, improving distance, reliability and speed. Up to four data streams can be sent simultaneously using 20MHz or 40MHz channels, providing a theoretical maximum data rate of 600 Mbps. See MIMO. "Wi-Fi CERTIFIED n" and Draft-2.0 The official "Wi-fi CERTIFIED n" standard was ratified in 2009; however, the Wi-Fi Alliance released a preliminary "Draft-2.0" specification in 2007, also called "Draft-N," to promote interoperability among early equipment. Even before Draft-N, vendors offered "Pre-N" products. See MIMO, 802.11 and 802.11ac.