Performance Comparison of Non-linear Precoding Schemes for Multi-user MIMO Broadcast Channels

Combined with block diagonalization (BD) methods, Tomlinson-Harashima (TH) precoding and vector perturbation (VP) are attractive non-linear precoding techniques for multi-user multiple-input multiple-output (MU-MIMO) broadcast channels. In this paper, we first briefly review several nonlinear precoding schemes including BD-VP, TH and zero-forcing (TH-ZF) and TH-VP, and then derive the achievable sum rate of the hybrid TH-VP precoding. After that, we compare the achievable sum rates and diversity gains of these non-linear precoding schemes with zero-forcing VP (ZF-VP) and dirty paper coding (DPC). The achievable sum rate of TH-VP is shown to approach the sum capacity of DPC asymptotically and outperforms BD-VP, TH-ZF and ZF-VP.