Abstract: For MIMO-OFDM channel estimation,a scheme of LS(least square) channel estimation in time domain is proposed.The basic idea of the scheme is that pilot signals of the transmitter and the receiver in time domain are used to calculate the channel response in time domain.To obtain the minimum mean square error(MMSE) in LS channel estimation,a design scheme for optimal pilot sequences is also proposed,and it is needed that not only the placement of pilot tones is of equal spacing in the frequency domain,but also the pilot positions are orthogonal to each other in different antennas.An LS-based parametric channel estimator(LSPCE) is also presented.The proposed algorithm gives much better performance than conventional LS algorithm and has lower computational complexity than conventional LSPCE.Simulation results and performance analysis validate the effectiveness of the proposed approach.