Performance Analysis and Training Power Allocation for Channel Estimation of MIMO/OFDM Systems Using Superimposed Training

This paper deals with the problem of channel estimation for multiple-input multiple-output/orthogonal frequency-division multiplexing (MIMO/OFDM) systems based on superimposed training (ST). Channel coefficients are firstly estimated by judicious designing superimposed pilot sequences across different users. Then, we analyze the channel estimation performance and derive a closed-form expression for estimation variance. For wireless communications with a limited power, we optimize the ST power allocation by maximizing the lower bound of the average channel capacity. Illustrative simulation examples are provided.