MIMO antenna system for multi-user multi-stream orthogonal space division multiplexing

The use of multiple-input multiple-output (MIMO) antennas for achieving diversity and/or support of multi-stream signaling has recently been demonstrated to gain lots of benefits including reduction in average power error probability and capacity enhancement. However, studies are limited to a point-to-point communication. In this paper, we address the optimization problem of enhancing the performance of a downlink multi-user system (i.e., point-to-multipoint communication) through joint use of multiple antennas at the base station (BS) and mobile stations (MS). The optimization is performed by finding the antenna weights at the BS and MS, jointly, to orthogonalize the multi-user multi-stream signals as well as maximizing the resultant channel gains of the diagonalized system for optimal performance.