基于导频和循环前缀联合的OFDM系统频率同步算法

正交频分复用（OFDM）是一种高效的数据传输技术,具有良好的抗衰落能力,可实现并行传输.但是OFDM对同步误差十分敏感,特别是频率同步误差.传统的基于导频和循环前缀的算法虽对频偏估计很有效,但计算复杂度较高.该文在联合算法的基础上提出了一种改进的频率同步算法.该算法通过简化最大似然函数降低了频偏估计的计算复杂度并提高了估计性能.通过仿真表明,在信噪比较高时,改进的算法频偏估计性能更优于联合算法.

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.