The Correcting Algorithms Of Carrier Frequency Offset In Orthogonal Frequency Division Multiplexing (OFDM) Systems

Because of its high spectrum utilization and good capability of preventing from muti-path interference, OFDM has been extensively used in the area of radio communication systems it is regarded as the core technology in Beyond 3G mobile communication system. However, carrier frequency offset is the main drawbacks of OFDM system, it can make the SNR lower, cause loss of sub-carrier orthogonality, and thus can introduce inter-channel interference (ICI) and severely degrade the system performance. Carrier frequency offset is the key problem of the use of OFDM. So researchers recently focus on the study of the correcting algorithms of carrier frequency offset.In this paper, the basic principles, the core technologies and the advantages of OFDM are introduced, the effect of carrier frequency offset is proposed. The algorithm based on the aid of pilot symbols and its improved algorithms are proposed, through the simulations, the conclusions are thus addressed that the improved algorithms can outperform the traditional ones in Estimation precision and ranges. Then, Analyses and compares Four Correcting of Carrier Frequency Offset methods—maximum-likelihood based on CP, MUSIC-Like, ESPRIT-Like and Cyclostationarity. Finally, the simulation results employing different algorithms are compared, the performance of Sch-Cox algorithm and its improved algorithm are best, the blind estimation algorithms are better, Cyclostationarity algorithm among Sch-Cox algorithm and blind estimation algorithm, maximum-likelihood based on CP algorithm is less.