Soft Decision-Directed Channel Estimation for Multiuser MIMO Systems

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 coarse knowledge of channel state information at the transmitter (CSIT), co-scheduled mobile users may suffer large residual multiuser interference in MU-MIND system. In this paper, we propose a new channel estimation technique using virtual pilot signals for the MU-MIMO OFDM systems. In a nutshell, we choose reliable data tones from both desired and interfering signals as virtual pilot signal and improves the channel estimation quality using iterative detection and decoding (IDD) scheme. We show that the proposed method achieves substantial performance gain over conventional approaches employing single user detection or multiuser detection.