Motivated by the rapid growth of wireless applications with multiple antenna terminals, multiple input multiple output (MIMO) relaying has gained much attention now a days due to its improved data rate, coverage extension and improved signal to noise ratio (SNR).
Multiple antenna wireless systems, and particularly multiple input multiple output (MIMO) systems, yield unprecedented possibilities of innovation in wireless communications.
Multiple antenna systems, such as Multiple-Input-Multiple-Output (MIMO), can create spatial diversity by taking advantage of multiple antennas and significantly increase the wireless channel capacity.
The idea of multiple antenna arrays has evolved into multiple-input multiple-output (MIMO) system, which provides transmit and receive diversities.
Wireless communication systems are already exploiting powerful multiple antenna technologies based on the principles of multiple input multiple output (MIMO) communication.
Multiple antenna systems can be realised for example as multiple input multiple output (MIMO) antenna systems allowing the automatic switching between multiple data streams or transmit diversity, in order to either optimise the throughput or the radio coverage, depending on the radio channel.
In this chapter, multiple access control (MAC) for mmWave massive multiple input multiple output (MIMO) is covered with a focus on user scheduling for spatial-division multiple access based on multiple antenna transmission.
The framework of the interference channel has been relaxed in [19] to include cognitive radio systems with transmitters and receivers equipped with multiple antennas, that is, multiple input multiple output (MIMO) systems.
One of the best ways to increase the transmission capacity and the reliability of a wireless system consists in using multiple antennas at transmission [known as multiple-input single-output (MISO) systems], reception [single-input multiple-output (SIMO) systems] or both at transmission and reception [multiple-input multiple-output (MIMO) systems] [2, 3].
The multiple-input multiple-output (MIMO) radar uses multiple antennas to simultaneously transmit several non-coherent waveforms and exploits multiple antennas to receive the reflected signals (echoes).
