Various Techniques for Frequency Offset Estimation in OFDM System: A Survey

The rapid growth in the wireless technology possess the need of high data rate transmission. This can be accomplished by using Orthogonal Frequency Division Multiplexing (OFDM). It is a particular case of multicarrier modulation (MCM), where high rate data stream is transmitted over low rate subcarriers. The system uses a number of carriers to transmit data simultaneously. The disadvantage of this system is its sensitivity to frequency offset and multipath delay spread as the spectra of OFDM signal is not strictly band limited which causes ICI (inter carrier interference) and ISI (inter symbol interference), resulting in loss of orthogonality between the subcarriers and thereby degrade the system performance. This paper presents various important techniques to estimate the frequency offset in OFDM system. Index Terms – Frequency offset; Inter carrier interference (ICI); Inter symbol interference (ISI); Cyclic Prefix (CP); crosscorrelation; Kalman Filter; Orthogonal Frequency Division Multiplexing (OFDM).