MIMO refers to Multiple Input, Multiple Output. It refers to a technology that allows the cellular signal to double or quadruple its bandwidth by utilizing multiple parallel data streams at the same time. It achieves this by using a different polarization for each stream of data. A separate antenna is needed for each stream, and the angle of each antenna must be offset from each other to align with its particular polarization. Even within just one frequency band, we can have up to 4 parallel steams of MIMO data. This is a big bandwidth enhancement.