Wide-Range Frequency Offset Estimation Algorithm for Optical Coherent Systems Using Training Sequence

A wide-range frequency offset estimation algorithm is proposed for optical coherent systems, which removes the modulated phase information from the received signal accurately using training sequence instead of traditional
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th power operation. A large frequency offset approximating to ±0.5 times the symbol rate can be traced in arbitrary
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-ary phase-shift-keying (MPSK)
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-ary quadrature amplitude modulation (MQAM) systems by the proposed algorithm with the low computational complexity and the negligible training overhead.