Smart antennae are antenna arrays with smart processing algorithms and are used in identifying spatial signals. A smart antenna takes advantage of the diversity effect at either the source (transmitter), the destination (receiver), or both. The diversity effect increases data speed and reduces error by combining the transmission and/or reception of multiple radio frequency (RF) waves. Smart antenna technology can overcome previous capacity limits as well as improve signal quality all while operating on less power. Smart antennae are also known as adaptive array antennae and multiple antennae. 
MISO – Multiple Input, Single Output
MISO is an antenna technology in which multiple antennas are used at the source (transmitter). The antennas are combined to minimize errors and optimize data speed. The destination (receiver) has only one antenna.
MISO technology has applications in digital television (DTV), wireless local area networks (WLANs), metropolitan area networks (MANs), and mobile communications. 
SIMO – Single Input Multiple Output
SIMO is an antenna technology which uses only one transmitting antenna and multiple
antennas at the receiving end; this helps to increase the diversity at the
receiving end as compared with a standard antenna.
SIMO technology has been previously used in mobile communication devices but is largely being replaced with MIMO technology. 
MIMO – Multiple Input Multiple Output
MIMO is an antenna technology utilizing multiple antennas at the transmitter and receiver to enable a variety of signal paths to carry the data, choosing separate paths for each antenna to enable multiple signal paths to be used.
MIMO technology is currently being used in Wi-Fi, LTE; Long Term Evolution, as well as various other radio and wireless technologies. There are many MIMO wireless routers on the market, and as this technology is becoming more widespread.  Many emerging FSO groups have begun researching MIMO as a viable FSO communication technique.