WLAN中OFDM系统载波频率同步算法研究  

Research on frequency synchronization algorithms for OFDM in WLAN

作　　者：单丽芳[1] 吴皓威[1] 杨士中[1] 

机构地区：[1]重庆大学通信工程学院,重庆400030

出　　处：《电子技术应用》2010年第5期125-128,共4页Application of Electronic Technique

基　　金：国家发改委CNGI示范工程(CNGI-04-4-2D)

摘　　要：针对OFDM技术中的载波频率同步问题,分析了载波频率偏差对OFDM系统造成的影响,总结了基于IEEE802.11标准的三种常见的频偏估计算法:基于循环前缀的最大似然算法、基于训练序列的时域相关算法和基于导频的频域相关算法,提出一种基于训练序列和导频的联合载波频偏估计算法。性能仿真结果表明,该联合估计算法在估计范围和估计精度上具有明显的优势,适合实际工程应用。Once the carrier frequency offset （CFO） exists, the orthogonality among subcarriers will be destroyed, which will cause inter-carrier interference （ICI）. The effect of frequency offset for OFDM is analyzed, and three classical algorithms for CFO estimation based on the structure of IEEE 802.11 is summarized, that is, maximum likelihood （ML） algorithm based on cyclic prefix, time-domain correlation algorithm based on short training sequences, and frequency-domain correlation algorithm utilizing based on pilots. Then a combined estimation algorithm based on both short training sequences and pilots is proposed in the paper. Simulation result shows that proposed algorithm outperforms the three classical algorithms in both the estimation range and accuracy, especially when the initial frequency offset is large, which is required in practice.

关 键 词：无线局域网 正交频分复用 载波同步 频率同步 

分 类 号：TN929.5[电子电信—通信与信息系统]