A Unified Linear Precoding Design for Multi-user MIMO Systems

We address the problem of the bit-error-rate (BER) performance gap between the sub-optimal and optimal linear precoder (LP) for a multi-user (MU) multiple-input and multiple-output (MIMO) broadcast systems in this paper. Particularly, mobile users suffer noise enhancement effect due to a sub-optimal LP that can be suppressed by an optimal LP matrix. A sub-optimal LP matrix such as a linear zero-forcing (LZF) precoder performs in high signal-to –noise-ratio (SNR) regime only, in contrast, an optimal precoder for instance a linear minimum mean-square-error (LMMSE) precoder outperforms in both low and high SNR scenarios. These kinds of precoder illustrates the BER gap distance at least 0.1 when it is used in itself in a MU-MIMO systems. Thus, we propose and design a unified linear precoding (ULP) matrix using a precoding selection technique that combines the sub-optimal and optimal LP matrix for a multi-user MIMO systems to ensure zero BER performance gap in this paper. The numerical results show that our proposed ULP technique offers significant performance in both low and high SNR scenarios.