中文摘要：

最大后验概率（maximum a posteriori,MAP）信道估计算法应用于MIMO-OFDM系统时将带来大规模矩阵求逆和乘积运算,且OFDM符号的数据传输效率随着发送天线的增多逐渐下降。针对这些弊端,提出一种基于期望最大化（expectation maximum,EM）的MAP信道估计算法,并分析了算法的性能。该算法利用EM算法把多输入输出信道估计问题化简为一系列独立的单输入输出问题,避免了大规模矩阵运算,降低了MAP算法的计算复杂度;为进一步改善MAP算法的数据传输效率及其估计性能,可通过对多个连续的OFDM符号进行联合信道估计。通过仿真实验证明了该算法的有效性。

英文摘要：

The channel estimation algorithm of maximum a posteriori （MAP） generates large matrix inversion and multiplicative operation when it is applied to multiple input multiple output with orthogonal frequency division multiplexing （MIMO-OFDM） systems. In addition, the data transmission efficiency will be declined with the increasing number of transmit antennas. Aiming at these problems, an expectation maximum （EM） based MAP algorithm is proposed and the performance is analyzed. The proposed algorithm avoids large matrix operations by using the EM algorithm to decompose the MIMO channel estimation problem into a series of single input single output （SISO） problems. Besides, a joint estimation is carried out over multiple OFDM symbols in order to enhance the data transmission efficiency and the estimative performance of the proposed al- gorithm. The effectiveness of this scheme is verified by several simulation experiments.