Robust transceiver design for up-link multi-user multiple-input multiple-output system with amplify-and-forward relay

Abstract

The robust transceiver design in dual-hop up-link multi-user multiple-input multiple-output (MIMO) system with amplify-and-forward relay is presented in this paper. Different from the most existing works, a complex channel model is adopted, the antenna correlation at both ends of the channel and the channel estimation errors are taken into account. The proposed design method provides a joint iterative design. Specifically, an optimization problem based on minimum mean-square error is firstly formulated, then the optimal relaying matrix is derived by Lagrangian multiplier method. Subsequently, the equalizer is optimized by a gradient-based line search algorithm and an alternating algorithm is proposed for the joint design. It is observed that the proposed design approach achieves better BER performance against imperfect channel state information errors than other approaches, which can demonstrate the effectiveness of the proposed approach.