A method of iterative channel estimation is proposed for orthogonal frequency division multiplexing(OFDM) system using superimposed training sequence with iterative receiver.The training sequence is exploited to get an initial channel estimate such that the iterative decoding process can be started.After each decoding iteration

the updated log likelihood ratio(LLR) of a posteriors probabilities on the coded bits are used to estimate the transmitted data symbols

which are fed back and used to improve channel estimates.Theoretical analysis of the mean square error(MSE) of the channel estimates is presented.In frequency selective fading channel

computer simulations of MSE perfonnance of the channel estimation method and bit rrror rate(BER) performance of the system under different conditions are given

which demonstrate the efficiency and validity of the proposed method.