To improve transmission efficiency, Expectation Maximization ( EM) based channel parameters estimation iteration algorithm is proposed, employed the special features of Orthogonal Frequency Division Multiplexing ( OFDM) system. 为提高OFDM系统的传输效率,考虑正交频分复用(OFDM)系统的特殊结构,该文提出一种使用少量导频的EM(Expectationmaximization)迭代信道参数估计算法。