Iterative Maximum Likelihood Estimation for Time and Integer Frequency Offset in OFDM Systems

In this paper the problem of integer frequency offset and time synchronization for orthogonal frequency division multiplexing (OFDM) systems is considered. An improved algorithm for time and integer frequency offset estimation is derived based on maximum likelihood (ML) technique and the differential information between two consecutive data symbols under the AWGN channel. In this algorithm, an iterative technique is used to obtain the estimation of time and normalized integer frequency offset when conducting global maximum of log-likelihood and calculating initial seed