Channel covariance information based transceiver design for AF MIMO relay systems with direct link

Abstract

Abstract-In this paper, we propose a design scheme for amplify-and-forward multiple-input multiple-output (AF MIMO) relay system with direct link to minimize the mean-squared error (MSE) of the signal estimation at the destination. In the proposed design scheme, an optimal precoding matrix is derived with the assumption that the full channel state information (CSI) of the source-relay link and partial channel state information such as channel covariance information (CCI) of the relay-destination link are available at the relay. In practical cases, if the destination is closer to the source, the source-destination link cannot be ignored. Hence, in this paper, we assume that the relay knows the partial channel state information of the source-destination link. Based on this assumption, an iterative optimal covariance algorithm is developed to achieve the minimum MSE of the signal estimation at the destination. In order to reduce computational complexity of the proposed optimal covariance algorithm, a suboptimal covariance algorithm is proposed. A numerical example shows that the developed optimal covariance algorithm outperforms the conventional CCI based MSE algorithms.

Tomlinson-Harashima Precoding Based Transceiver Design for MIMO Relay Systems With Channel Covariance Information

“…To proceed further, we minimize the MSE function (19) with respect to the lower triangular and unit diagonal matrix C. The optimum C is given in [23] and can be written as…”

MMSE Based Transceiver Design for MIMO Relay Systems with Mean and Covariance Feedback

“…This benefits can be incorporated into the cooperative communication systems by deploying multiple antennas at the transceiver. Due to this fact, non-regenerative multiple input multiple output (MIMO) relay systems have received much research interest [1]- [11].…”

“…In [7] and [8], optimal precoder is designed for maximizing the ergodic capacity of the non-regenerative MIMO relay systems with the assumption that the channel covariance information (CCI) of the relay-destination link is available at the relay node. Recently, minimum mean-squared error (MMSE) based transceivers are investigated in [9]- [11] with the assumption that the relay knows the covariance channel information of the relay-destination link. However, the optimal precoding matrix with the mean feedback of the relay-destination link was not investigated in [9]- [11].…”

“…Recently, minimum mean-squared error (MMSE) based transceivers are investigated in [9]- [11] with the assumption that the relay knows the covariance channel information of the relay-destination link. However, the optimal precoding matrix with the mean feedback of the relay-destination link was not investigated in [9]- [11].…”