Symbol Synchronization and Frequency Offset Estimation Schemes in Optical OFDM Systems

Recent patents and approaches of symbol timing and frequency offset estimation in optical OFDM systems are reviewed. The synchronization methods utilizing the training sequence or cyclic prefix are discussed and compared. The processing approaches includes subtraction, low-power DC offset, auto- and cross-correlation schemes.The synchronization methods have been evaluated in terms of the efficiency and complexity. It is shown that, by determining the optimal length of the non-zero pattern of the training sequence, synchronization algorithm using simplified auto-correlation scheme can achieve both of the accuracy and low complexity for optical OFDM systems.