Power Allocation for SLNR Precoding based on MMSE Criterion in Multiuser MIMO System

Abstract In order to fulfill the rapid increasing demands of the broadband multimedia and wireless communication, the Multi-input multi-output (MIMO) technique serving as one of the key technologies of the physical layer, have drawn a lot of attention in the past few years. Multi-user multiple-input multiple-output (MU-MIMO) wireless communication system has rapidly gained in popularity over the past decade due to its promising improvement in terms of system capacity and transmission quality without incurring extra bandwidth or transmission power. Multi-user interference (MUI) is one of the major impairments on the performance of multi-user multiple input multiple-output (MU-MIMO) wireless communication system. Signal-to-leakage-and-noise ratio (SLNR) precoding suppresses MUI and provides a closed form solution to the coupling problem encountered in the conventional designs based on maximizing signal-to-interference-and-noise ratio (SINR). In this paper, to enhance the transmission quality for SLNR precoding in the MU-MIMO downlink communication, an iterative power allocation scheme is proposed. Based on minimum total mean square error criterion (MMSE), subject to a total transmit power constraint, power allocation factors, precoding and decoding matrix are regenerated and updated in turn iteratively. A local optimal solution could be solved in this alternating optimization. Simulation results demonstrate the improved bit error rate (BER) performance and the convergence of MSE of the proposed scheme.