Power Allocation for Maximizing Sum Capacity of Multiuser MIMO Downlink with Transmit Precoding Based on SLNR

Designing transmit precoding vectors based on maximizing signal-to-leakage-and-noise ratio (SLNR) provides a practical solution to the coupling problem encountered in the conventional designing methodology by maximizing signal-to interference-plus-noise ratio (SINR). In this contribution, a simple but sophisticated iterative algorithm is proposed to find the optimal power allocation for the sake of increasing the sum capacity of the multiuser (MU) multiple-input-multiple-output (MIMO) downlink system. A sub-optimal power allocation scheme is also proposed for improving the sum capacity while limiting the system complexity. Simulation results are provided to demonstrate that our proposed power allocation schemes are capable of improving the sum capacity of the MU-MIMO downlink system.