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Optimal training for MIMO time-selective fading channels

Carrier frequency offsets and mobility induced Doppler shifts introduce time-selective in wireless links. To mitigate the resulting time-selective, in this paper, optimal training sequence was designed for linear minimum mean square error (LMMSE) estimation of multi-input multi-output time-selective channels by maximizing a lower bound on the average capacity while at the same time minimizing the mean-square channel estimation error. Optimal number and placement of pilot symbols are also analyzed. Numerical analysis and simulation corroborate our theoretical designs.