Successive Zero-Forcing DPC With Sum Power Constraint: Low-Complexity Optimal Designs
Successive Zero-Forcing Dirty Paper Coding (SZFDPC) is a simplified alternative to DPC for MIMO Broadcast Channels (MIMO BCs). In the SZF-DPC scheme, the non-causally known interference is canceled by DPC, while the residual interference is suppressed by the ZF technique. Due to the ZF constraints, the precoders are constrained to lie in the null space of a matrix. For the sum rate maximization problem under a sum power constraint, the existing precoder designs naturally rely on the Singular Value Decomposition (SVD). The SVD-based design is optimal but needs high computational complexity. Herein, the authors propose two low-complexity optimal precoder designs for SZFDPC, all based on the QR Decomposition (QRD), which requires lower complexity than SVD.