Oblique projection based linear precoding for downlink multi-user multiple-input multiple-output communications

In this paper, we investigate linear precoding and scheduling algorithms for downlink multi-user multiple input multiple output (MU-MIMO) systems. In order to eliminate the multi-user interference and improve the bit error rate (BER) system performance, block diagonalization precoding could be combined with geometric mean decomposition (BD-GMD) scheme. We propose GMD linear precoding approaches utilizing oblique projection (OP-GMD). This paper also derives system capacity in closed-form through applying water-filling power allocation algorithm into the system model. Our simulation results show that the proposed scheduling algorithms perform better with the increase of the number of transmit antennas. In terms of system capacity, the proposed OP-GMD algorithms significantly outperform the precoding scheme based on BD-GMD at low SNRs.