Linear Precoding Scheme Design for MIMO Two‐Way Relay Systems with Imperfect Channel State Information

Abstract

The aim of this paper is to investigate a linear precoding scheme design for a multiple-input multiple-output two-way relay system with imperfect channel state information. The scheme design is simplified as an optimal problem with precoding matrix variables, which is deduced with the maximum power constraint at the relay station based on the minimum mean square error criterion. With channel feedback delay at both ends of the channel and the channel estimation errors being taken into account, we propose a matrix decomposition scheme and a joint iterative scheme to minimize the average sum mean square error. The matrix decomposition method is used to derive the closed form of the relay matrix, and the joint iterative algorithm is used to optimize the precoding matrix and the processing matrix. According to numerical simulation results, the matrix decomposition scheme reduces the system bit error rate (BER) effectively and the joint iterative scheme achieves the best performance of BER against existing methods.

Interference Management in LTE-Advanced Cooperative Relay Networks: Decentralized Transceiver Design With Channel Estimation

“…Numerical evaluations are provided to prove the benefit of this cooperative RN extension over a simple MU-MIMO system. -In pratical networks, a perfect CSI is impossible to obain due to limitation of channel estimation [34]. The authors in [28] considered a perfect CSI, which is not a practical scenario.…”

“…In this regard, the BER evaluation of the channel estimation errors effect is further conducted for the proposed transceiver design for the FAPs, MUEs and UEs at both time slots. Just like [34], we consider the case of imperferct CSI scenario with LS and MMSE channel estimators for a realistic network scenario. The BER performance evaluation versus different value of σ 2 ε for the MUEs during the first time slot is shown in Fig.…”