关键词: MIMO-OFDM系统, SAGE算法, 改进的FD-SAGE算法, 信道估计

Abstract: Aiming at the poor performance of Frequency Domain Space-Alternating Generalized Expectation-Maximization（FD-SAGE） algorithm in channel estimation and the slow convergence speed in the MIMO-OFDM system, this paper presents an improved FD-SAGE channel estimate algorithm. On the basis of FD-SAGE algorithm, a modified SAGE algorithm is derived through decomposing and analyzing the potential and incomplete data of SAGE algorithm. Meanwhile, the maximum likelihood algorithm is introduced in the process of refreshing data information in SAGE algorithm, and then the reliability of system is improved. The theoretical analysis and simulation results show that this algorithm can better track the channel change and acquire a faster convergence speed, just in cost of a slight system complexity. The performance is better than the traditional Least Square（LS） algorithm. Comparing with the ideal channel estimation under the maximum likelihood algorithm in signal detection, the new proposed algorithm has only a loss of 0.5 dB with the same bit error rate.

Key words: MIMO-OFDM system, SAGE algorithm, improved FD-SAGE algorithm, channel estimation