Channel estimation for frequency-selective two-way MIMO relay systems
Choo W. R. Chiong, Yue Rong, Yang Xiang · eSpace (Curtin University) · 2014
Abstract—In this paper, we investigate the channel estimation problem for two-way multiple-input multiple-output (MIMO) relay communication systems in frequency-selective fading en-vironments. We propose a superimposed channel training al-gorithm to estimate the individual channel state information (CSI) of the first-hop and second-hop links for two-way MIMO relay systems with frequency-selective fading channels. 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. We also derive the optimal power allocation between the source and relay training sequences. Numerical examples are shown to demonstrate the performance of the proposed algorithm. Index Terms—Channel estimation, MIMO two-way relay, frequency-selective fading, superimposed training, MMSE I.