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/sub s/) and a passive weighting process. This process selects n/sub r/ < n/sub s/ out of n/sub 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 be achieved using the passive receive beamformer but with less radio frequency (RF) chains.