| Due to high proficiency with high bandwidth efficiency, orthogonal frequency division multiplexing (OFDM) has been selected for broadband wireless communication systems. Since OFDM can provide large data rates with sufficient robustness to radio channel impairments, and due to its robustness against the multipath delay spread, OFDM has always been a designated technique for broadband wireless communication mobile systems. Nevertheless, OFDM suffers from Carrier Frequency Offset (CFO). CFO has been recognized as a major disadvantage of OFDM. CFO can lead to the frequency mismatch in transmitter and receiver oscillator. Lack of the synchronization of the local oscillator signal (L.OSC), for down conversion in the receiver with the carrier signal contained in the received signal, can cause the performance of OFDM to degrade. In other words, the orthogonality of the OFDM relies on the condition that the transmitter and receiver operate with exactly the same frequency reference. If this is not the case, the perfect orthogonality of the subcarrier will be lost, which can result in CFO. In this research, the source of creating CFO and the major CFO estimation algorithms have been reviewed and discussed in literature. We then proposed some algorithms and techniques for estimating and compensating for the effect of CFO. We showed that our proposed methods have a better performance with low complexity. |
