Iterative channel estimator and equalizer for OFDM modulation systems

In OFDM system, frequency offset will cause intercarrier interference (ICI). This will degrade severely the accuracy of channel equalization when one tap equalizer is used. In this paper, we discuss the effects of ICI on the OFDM signals, and develop an iterative equalization algorithm to cancel the ICI from the OFDM signals. In theory, the ICI can be cancelled completely by the iterative algorithm when a perfect estimated frequency offset is provided. In practice, if a fine frequency offset can be estimated, the iterative algorithm can then be employed to reduce the ICI effect remarkably. To reduce the complexity of the iterative equalizer, some simplified algorithms have been studied and proposed for practical implementation.