802.11n

An IEEE 802.11 wireless network standard that increases transmission speeds to 150 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).

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 standard was ratified in 2009 (Wi-Fi CERTIFIED n); however, the Wi-Fi Alliance released a preliminary specification in 2007 so that equipment from different vendors would interoperate. Called "Draft 2.0" and "Draft-N," firmware updates are required to bring such devices into official compliance. Even before Draft 2.0, vendors offered proprietary "Pre-N" products using MIMO and 802.11n methods. See MIMO and 802.11.

Pre-N Equipment

Prior to Draft 2.0, Belkin released this wireless router with two transmitters and three receivers to deliver up to 108 Mbps. Both sides of the transmission had to be Belkin devices. (Image courtesy of Belkin Corporation, www.belkin.com)

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