MIMO is defined in two ways, the first as a radio communications technology, or RF technology, in which multiple antennas are used at both the source (transmitter) and the destination (receiver). The second is as a practical technique for sending and receiving more than one data signal simultaneously over the same radio channel by exploiting multipath propagation.
MIMO technology has been standardized for wireless LANs, 3G and 4G mobile phone networks, and is now in widespread commercial use. MIMO can be sub-divided into three main categories: precoding, spatial multiplexing (SM), and diversity coding.
In 2010, the IEEE defined MINO as: Cooperative multiple-input multiple-output technology allows a wireless network to coordinate among distributed antennas and achieve considerable performance gains similar to those provided by conventional MIMO systems. It promises significant improvements in spectral efficiency and network coverage and is a major candidate technology in various standard proposals for the fourth-generation wireless communication systems. For the design and accurate performance assessment of cooperative MIMO systems, realistic cooperative MIMO channel models are indispensable. This article provides an overview of the state of the art in cooperative MIMO channel modeling. We show that although the existing standardized point-to-point MIMO channel models can be applied, to a certain extent, to model cooperative MIMO channels, many new challenges remain in cooperative MIMO channel modeling, such as how to model mobile-to-mobile channels, and how to characterize the heterogeneity and correlation of multiple links at the system level appropriately.
The full article can be found here: http://ieeexplore.ieee.org/abstract/document/5402668/