MIMO capacity improvement using smart passive receive antennas

This paper presents a novel structure to enhance the capacity of Multi-Input and Multi-Output (MIMO) systems using the passive smart antenna concept. The proposed structure consists of a large number of receive antenna elements (n(s)) and a passive weighting process. This process selects n(r) < n(s) out of n(s) antennas after weighting them properly in such a way that to enhance the capacity. The simulation results show that when the number of the receive antenna elements increases beyond a limit, the capacity improves significantly. Furthermore, the same performance as full-complexity MIMO structure can he achieved using the passive receive beamformer but with less Radio Frequency (RF) chains.