Abstract: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. Channel impulse response is updated at each iteration, furthermore the noise variance is update also. To improve the algorithm convergence, EM-based joint channel parameters estimation and data detection algorithm is proposed. Simulation results demonstrate the proposed EM-based algorithm can converge to the case with known channel parameters with fewer pilots and the joint channel parameters estimation and data detection algorithm converges significantly fast.