Enhanced multi-user eigen channel selection for MIMO downlink transmissions

In this paper, we propose an enhanced multi-user eigen channel selection (E-MES) solution for multiple-input multiple-output (MIMO) multi-user downlink transmissions exploiting sequential projection and zero-forming (ZF) algorithm. In the existing solutions, eigen channel of each candidate user was pre-defined at the start of the multi-eigen selection, and this limits user's eigen channel adaptation by the prior knowledge of selected eigens. In E-MES, a successive optimal eigen channel selection is executed during the multi-eigen channel selection, and those procedures can guarantee the selected eigen channel at each step provide more larger contribution to the system sum-rate performance. Furthermore, E-MES can optimize the selected eigen channel set in term of the maximum system sum-rate. Both theoretical analysis and multiple numerical simulations are provided to demonstrate that E-MES solution outperforms some existing dominant solutions, such as L-MDES and L-MES. Although E-MES is proposed for single cell multi-user downlink transmission, it can also be directly extended to the multi-cell multi-user cooperative downlink transmission scenario.