改进CAZAC序列的OFDM时频同步算法  

OFDM timing and frequency synchronization algorithm based on weighted CAZAC sequence

作　　者：刘彬[1] 罗志年[1] 彭疆[1] LIU Bin;LUO Zhinian;PENG Jiang(College of Computer Science and Electronic Engineering, Hunan University, Changsha 410082, China)

机构地区：[1]湖南大学信息科学与工程学院,长沙410082

出　　处：《计算机工程与应用》2017年第14期76-79,98,共5页Computer Engineering and Applications

基　　金：国家自然科学基金(No.61371115);湖南省教育厅资助重点科研项目(No.11A065)

摘　　要：针对先前一些算法存在定时模糊以及存在较大干扰峰干扰的问题,提出了一种基于加权CAZAC序列的OFDM系统同步方案。利用训练序列共轭对称特性进行符号定时和频偏估计。利用训练序列延迟相关和对称相关的特点进行定时和粗频偏估计,能够有效抑制干扰从而得到更好的估计性能。利用循环前缀的冗余信息进行小数倍频偏精细估计。此外分析了整数倍频偏对时域CAZAC序列的影响。采用时域循环移位进行整数倍频偏估计。通过与其他算法的仿真对比可以得出,多径衰落信道下所提算法能够取得较高的定时准确率和频偏估计精度。In this paper,a novel preamble structure based on weighted CAZAC(Constant Amplitude Zero Auto Correlation)sequence is designed to solve timing ambiguity and high interference peak.The conjugate symmetry of training sequenceis used for symbol timing and frequency offset estimation.Then with the redundancy of the cyclic prefix,the fine fractionalfrequency offset is completed.Finally,the cyclic shifting operation in time domain is adopted to estimate the integer frequencyoffset.Analysis and computer simulation results show that the proposed method achieves high timing and frequencyoffset estimation accuracy compared with other algorithm,and solves the problem of synchronization inaccuracy undermultipath fading channel.The proposed method has important significance for improving the performance of OFDM systemunder multipath fading channel environment.

关 键 词：正交频分复用 同步 恒包络零自相关序列 多径衰落信道 

分 类 号：TN911[电子电信—通信与信息系统]