Channel estimation for two-way MIMO relay systems in frequency-selective fading environments

In this paper, we investigate the channel estimation problem for two-way multiple-input multiple-output(MIMO) relay communication systems in frequency-selective fading environments. We apply themethod of superimposed channel training to estimate the individual channel state information (CSI) ofthe first-hop and second-hop links for two-way MIMO relay systems with frequency-selective fadingchannels. In this algorithm, a relay training sequence is superimposed on the received signals at the relay node to assist the estimation of the second-hop channel matrices. The optimal structure of the source and relay training sequences is derived to minimize the mean-squared error (MSE) of channel estimation. Moreover, the optimal power allocation between the source and relay training sequences is derived to improve the performance of channel estimation. Numerical examples are shown to demonstrate the performance of the proposed superimposed channel training algorithm for two-way MIMO relay systems in frequency-selective fading environments

Efficient channel estimation algorithms for cooperative multiple-input multiple-output (MIMO) wireless communication networks

Multiple-input multiple-output (MIMO) relay communication systems have been identified to be one of the promising solutions to high rate wireless communications. In optimizing the MIMO relay networks, the knowledge of channel state information (CSI) is essential. This thesis develops novel channel estimation algorithms for MIMO relay communication networks, considering the amplify-and-forward relaying scheme. The proposed algorithms outperform existing schemes in estimating the CSI of each hop in MIMO relay networks