无线信道中OFDM系统时频同步新算法  

A novel OFDM time and frequency synchronization algorithm in wireless channel

作　　者：马章勇[1] 赵春明[1] 尤肖虎[1] 

机构地区：[1]东南大学移动通信国家重点实验室,江苏南京210096

出　　处：《通信学报》2003年第12期76-83,共8页Journal on Communications

基　　金：国家杰出青年基金资CNSF(69725001);江苏东大通信技术有限责任公司基金;西门子移动通信公司

摘　　要：OFDM系统中频偏和定时误差的存在,对系统性能有很大的影响。本文根据设计的特殊导颁符号,通过伪随机序列的自相关特性得到定时误差;然后通过导频符号之间的相关性,估计出频率偏离。为了提高估计器的精度,采用了过采样技术。同时可以证明该算法能有效地对抗无线信道中的码间干扰。仿真结果表明,该算法能获得很好的性能,逼近改进的Cramer-Rao下界。OFDM system performance is more sensitive to frequency offset and timing error than single-carrier systems. In this paper, the timing error is obtained by the autocorrelation characteristic of the pseudo noise sequence (PN-sequence) based on the special pilot symbols; then the frequency offset can be estimated grounded on the correlation of pilot symbols. In order to improve the accuracy of the estimator, oversampling technology is adopted. Moreover, the algorithm can robust the ISI (inter-symbol-interference) in the wireless channel. The simulation shows that the good performance is gained; the results approach the modified Cramer-Rao low bound (MCRB).

关 键 词：OFDM 频率偏离 定时误差 伪随机序列 CRAMER-RAO下界 码间干扰 无线信道 时频同步 

分 类 号：TN929.533[电子电信—通信与信息系统]