Advanced downlink MU-MIMO receiver based on modulation classification

Abstract

Multi-user multiple-input and multiple-output (MU-MIMO) transmission scheme, which provides extra spectral efficiency, is one of the most potential technologies in Third Generation Partnership Project Long Term Evolution (3GPP LTE) system. Because of a low resolution precoder and the coarse knowledge of channel state information (CSI), interference among co-scheduled user equipments (UEs) is inescapable. In this paper, we propose an interference aware strategy to mitigate the interference. To achieve an intended result, we formulate functions corresponding to signal detection and gain insight into some interference cancelation schemes. The acknowledged optimal receiver applying Max-Log-Likelihood (ML) criterion is our original springboard. Considering that ML criterion is restricted by its unacceptable computational effort, we suggest to estimate the modulation type of interference before the detection. So a simplified method named table look-up scheme (TLS) is brought into. Then we discuss the necessity of TLS and provide relevant proofs to show its feasibility. Finally, simulation results show that our TLS assisted ML (TLS-ML) criterion outperforms those conventional ones.