lereveurat

In radio, multiple-input and multiple-output, or MIMO (pronounced my-moh), is the use of multiple antennas at both the transmitter and receiver to improve communication performance. It is one of several forms of smart antenna technology.

MIMO technology has attracted attention in wireless communications, since it offers significant increases in data throughput and link range without additional bandwidth or transmit power. It achieves this by higher spectral efficiency (more bits per second per hertz of bandwidth) and link reliability or diversity (reduced fading). Because of these properties, MIMO is a current theme of international wireless research. (Refer to: Research trends in MIMO literature)

Principle

Arogyaswami Paulraj and Thomas Kailath proposed the concept of Spatial Multiplexing using MIMO in 1993. Their US Patent No. 5,345,599 issued 1994. on Spatial Multiplexing emphasized applications to wireless broadcast.

In 1996, Greg Raleigh and Gerard J. Foschini refine new approaches to MIMO technology, which considers a configuration where multiple transmit antennas are co-located at one transmitter to improve the link throughput effectively.

Bell Labs was the first to demonstrate a laboratory prototype of spatial multiplexing (SM) in 1998, where spatial multiplexing is a principal technology to improve the performance of MIMO communication systems.