This paper addresses the training signal design for the channel estimation in two-way multiple-input-and-multipleoutput (MIMO) relay systems, where the channels are correlated. We first derive the backward channel estimator with the optimal training signal sent by the relay node. Given the estimated backward channels and the probabilistic knowledge of the estimation error, we mainly focus on the forward channel estimation and the related training signal design. We further propose a novel training signal. The design criterion is to minimize the relaxation of the total mean square error (MSE) of the forward channel estimators, which is conditioned on the estimated backward channels. Finally, the numerical results show that the proposed training signal can improve the MSE performance.
翻译:本文涉及双向多投入和多流量中继系统(MIMO)的频道估算培训信号设计。 我们首先用中继节点发送的最佳培训信号来得出后向频道估计信号。 鉴于估计的后向频道和估计误差的概率,我们主要侧重于前向频道估算和相关的培训信号设计。 我们进一步提出一个新的培训信号。设计标准是尽量减少前向频道估计偏差(MSE)的总平均平方差(MSE)的放松,该差错以估计后向通道为条件。 最后,数字结果显示,拟议的培训信号可以改善MSE的性能。