Structure-based water-filling algorithm in multipath MIMO channels

Recent advances in information theory show that employing multiple antennas at both sides of a wireless channel promises enormous capacity potential. With perfect knowledge of channel state information (CSI) at the transmitter, eigen-beamforming is the optimal coding scheme to exploit this potential. However, in nonstationary wireless environments, high complexity on multiple-input-multiple-output (MIMO) channel tracking and large amounts of CSI feedback render such an approach impractical. By exploiting the wireless multipath channel structure characterized by the path delays and the path directions-of-departure/arrival, we propose a new space-time transmit scheme which employs a structure-based water-filling algorithm.