Abstract: One of the principal disadvantages of OFDM is very sensitive to frequency offset. Carrier frequency offset can be divided into two parts: an integer one and a fractional one. The integer frequency offset has no effect on the orthogonality among the subcarriers; however it cause a circular shift of data symbols in the receiver, resulting in a BER of 0.5. The maximum likelihood(ML) estimation algorithm for integer frequency offset is derived and it employs the difference relation between two consecutive OFDM symbols. The performance of the ML algorithm is evaluated and compared with the conventional method by computer simulations.

Key words: OFDM, integer frequency offset estimation, maximum likelihood algorithm