802.11n - Computer Definition
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 wireless network standard that increases transmission speeds to 300 Mbps and beyond. Because 802.11n works in both the 2.4 GHz and 5 GHz frequency bands, it is compatible with legacy 11a and 11b/g users (see dual-band router). Although the newer, faster 802.11ac standard is expected to proliferate starting in 2013, 802.11n devices will exist for quite some time. Multiple Antennas (MIMO) The key to 802.11n is the use of multiple antennas, which improve 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 equipment from different vendors. Even before Draft-N, vendors offered their own "Pre-N" products. See MIMO, 802.11 and 802.11ac.