Virtual pilot-based channel estimation and multiuser detection for multiuser MIMO in LTE-Advanced

Abstract

Multiuser multiple-input multiple-output (MU-MIMO) transmission technique based on orthogonal frequency division multiplexing (OFDM) system has been received great deal of attention in recent years due to its potential higher spectral efficiency. However, because of the accuracy of channel state information, co-scheduled mobile users may suffer large residual multiuser interference in MU-MIMO system. In this paper, we propose a new channel estimation technique using expectation and maximization (EM) algorithm with reliable soft symbols for the MU-MIMO systems in LTE-Advanced. In the proposed scheme, we choose reliable data tones from both desired and interfering signals and improves the channel estimation quality using iterative process between channel estimation and data detection in frequency domain. We show that the proposed method achieves substantial performance gain over conventional channel estimation approaches.