Low complexity non-linear pre-coding on downlink multiuser MIMO systems

Abstract

This paper proposes low complexity non-linear pre-coding that switching among pre-coding weights per orthogonal frequency division multiplexing (OFDM) symbol according to the modulation scheme and constellation point of users, for downlink multiuser multiple input multiple output (DL-MU-MIMO) systems. In the proposed pre-coding, when some users have the same modulation scheme and constellation point, the pre-coding weight is calculated based on broadcast approach without inter-user interference cancellation. If not, the pre-coding weight is calculated based on unicast approach such as the zero-forcing (ZF) method. In addition, computer simulation results show that the proposed pre-coding achieves lower bit error rate (BER) on low signal to noise ratio (SNR) environments.