Introduction
Multiple Input, Multiple Output (MIMO) technology, a necessary building block for 4G and evolved wireless technologies such as LTE and LTE-Advanced, is used to enhance the overall performance of radio transmitters and receivers with respect to the effects of the air interface. Multiple transmit and receive data paths are used in MIMO systems to provide significant increases in throughput and robustness by exploiting the characteristics of the radio channel. As a result, MIMO system performance is directly related to te propagation environment in which the device is operating