MSE-Based Precoder Designs for Transmitter-Preprocessing-Aided Spatial Modulation Under Per-Antenna Power Constraints

In this correspondence, we investigate mean-square-error-based precoder designs for transmitter-preprocessing-aided spatial modulation (PSM) multiple-input multiple-output (MIMO) systems. In contrast to the existing precoders that are designed almost exclusively under the average total power constraint (ATPC), we focus on design problems under more realistic per-antenna power constraints (PAPCs). We first identify two different types of PAPCs for PSM-MIMO systems, including the average PAPC and the strict PAPC (SPAPC). We then derive the associated optimal minimum mean square error (MMSE) and zero forcing (ZF) precoders under these two constraints. To achieve a more balanced performance-complexity tradeoff, suboptimal SPAPC precoder designs, including a linear-programming-assisted ZF/MMSE ATPC with a power backoff precoder, are proposed. Finally, the performance of the proposed precoders is demonstrated through numerical simulations.