An improved frequency synchronization method for OFDM systems based on combined cyclic prefix and pilot frame

Orthogonal frequency-division multiplexing(OFDM) is a highly efficiency technique for data transmission with good ability of anti-fading and parallel transmitsion.But OFDM is sensitive to synchr-onization error,especially to frequency synchronization error.Although traditional algorithm which combines cyclic prefix(CP)with pilot carrier is very effective to frequency offset estimation,its computational complexity is high.This paper proposes an improved frequency synchronization algorithm on the basis of previous algorithm.By simplifying the maximum likelihood function,the proposed algorithm reduces the computational complexity of frequency offset estimation and improves the capability of estimation.The result of simulation shows that the performance of the proposed frequency offset estimation algorithm is suprior to that of the algorithm combined cyclic prefix(CP) with pilot carrier in low SNR.