Linear Precoder and Equalizer Design for Uplink Multiuser MIMO Systems with Imperfect Channel State Information

Combined Transceiver Optimization for Uplink Multiuser MIMO with Limited CSI

“…the SMSE and averaged BER performance of the QR-EPD and SVD-EPD schemes are evaluated and compared with the transceiver design proposed in [7], denoted as SVD non-EPD. In both the SVD-EPD and SVD non-EPD schemes, the SVD is applied to decompose the matrix H into the matrixproduct form as follows:…”

“…The scalar μ in (12) is the Lagrangian multiplier. Similar to [7], a noniterative set of linear precoders and decoders are utilized by relaxing a nonconvex optimization problem in (10) into a simpler convex optimization problem. Thus, two traditional issues of the complexity cost and the convergence speed in most iterative-based algorithms can be avoided.…”

“…In order to obtain the optimal solution of F, the block-diagonal constraint on F needs to be relaxed for this moment. In what follows, the matrix of F opt is used to indicate the optimal solution of F. Instead of the singular value decomposition (SVD) used to decompose the matrix H in [7], the computationally efficient QR factorization is employed to perform the decomposition of the matrix H H H as follows:…”

“…Subsequently, the diagonal elements of Λ H is rearranged in a decreasing order. Finally, the matrix F opt can be attained by [5,7,10]…”

“…However, the knowledge of CSI is in general incomplete in reality due to various kinds of channel imperfections, such as channel estimation error, feedback delay, and finite-rate channel equalization. In addition, the development of the transceiver depends primarily on the complex iterativebased algorithms, in which they either suffer from a slow convergence rate at high signal-to-noise ratio (SNR) or may even not converge to global optimum [7]. Therefore, instead of relying on complicated recursive-based algorithms, an efficient noniterative QR-based transceiver design is proposed for uplink MU-MIMO systems under limited CSI at both sides.…”