Carrier Frequency Offset in OFDM

Orthogonal Frequency Division Multiplexing (OFDM) is a popular multicarrier modulation technique with the ability to provide high data rates over echo-ladened channels. It has excellent robustness to impairments caused by multipath, which includes frequency selective fading. Unfortunately, OFDM is very sensitive to the carrier frequency offset (CFO) that is introduced by the down conversion process. The objective of this book is to develop and analyze an algorithm for blind CFO recovery suitable for use with a practical zero-Intermediate Frequency (zero-IF) OFDM telecommunications system. A blind CFO recovery algorithm based upon characteristics of the received signal power spectrum is proposed. The algorithms error performance is mathematically analyzed and the theoretical results are verified with simulations. The simulation shows that the performance of the proposed algorithm agrees with the mathematical analysis. The proposed algorithm performs well in comparison and does not suffer from many of the disadvantages of existing blind CFO recovery techniques. Most notably, its performance is not significantly degraded by noisy, frequency selective channels.