With the global availability of Samsung Galaxy S5 today, you must be wondering what MIMO actually is, since Samsung boasts about this technology, which has been equipped in their latest flagship device.
MIMO (Multiple-Input-Multiple-Output) is a wireless technology that uses multiple transmitters and receivers to transfer more data at the same time . If a particular device has 802.11n, then that particular device is MIMO compatible. The transmitter and receiver antennas are combined to minimize errors and optimize data speed.
Before the introduction of MIMO, multipath effects were caused sometimes due to signal interference because single antennas were used at both ends of the communication link. When electromagnetic (EM) waves interfere with obstacles such as buildings and hills, the wavefronts get scattered and travel in different paths in order to reach the receiving end. This can lead to slow mobile internet speeds and data losses during transmission. At present, MIMO technology utilises these multipath effects to substantially increase the performance and range of transmission by using multiple, smart transmitters and receivers with an added spatial dimension. Higher speeds can be achieved with the availability of more antennas. For example, a wireless adapter consisting of three antennas can have a speed of 600 Mbps while an adapter consisting of two antennas has a speed of 300 Mbps.
The new iPad Air is another device which supports this groundbreaking technology .
The link given below further explains MIMO technology visually.
 Wireless Networking — What is Multiple-Input Multiple-Output (MIMO)?. 2014. Wireless Networking — What is Multiple-Input Multiple-Output (MIMO)?. [ONLINE] Available at:http://www.intel.com/support/wireless/sb/cs-025345.htm. [Accessed 11 April 2014].
 What is MIMO (multiple input, multiple output)? – Definition from WhatIs.com. 2014. What is MIMO (multiple input, multiple output)? – Definition from WhatIs.com. [ONLINE] Available at:http://searchmobilecomputing.techtarget.com/definition/MIMO. [Accessed 11 April 2014].
 Apple – iPad Air – Features. 2014. Apple – iPad Air – Features. [ONLINE] Available at: http://www.apple.com/ipad-air/features/. [Accessed 11 April 2014].
 2×2 MIMO antenna system 2014. . [ONLINE] Available at: http://mwrf.com/site-files/mwrf.com/files/archive/mwrf.com/files/30/21225/fig_01.gif. [Accessed 11 April 2014].