MIMO (Multiple Input/Multiple Output) **4G Technology**

*Another technology/technique involved in 4G communications

MIMO (Multiple Input/Multiple Output): MIMO is a wireless technology that employs multiple intelligent input and output radio antennas to improve transmission speed and quality over longer distances than otherwise possible. The technique involves Space Division Multiplexing (SDM), with arrays of multiple spatially separated transmit and receive antennas. The idea is to push 802.11 (also known as Wi-Fi) WLAN (Wireless Local Area Network) transmission rates from around 20 Mbps to at least 100 Mbps and perhaps as high as 540 Mbps. MIMO also will extend 802.11 distances from 100 meters to as much as 200 meters. MIMO is the basis for the developing IEEE 802.11n standard and promotes spectral efficiency during 4G communications. MIMO is typically combined with OFDM (Orthogonoal Frequency-Division Multiplexing) to achieve an even greater level of spectral efficiency.