基于PN序列的OFDM频偏估计与时间同步探讨  

Frequency Offset and Timing Synchronization for OFDM Utilizing PN Sequence

作　　者：聂永萍[1] 何先刚[1] 张忠培[2] 范时平[1] 

机构地区：[1]重庆邮电学院,重庆400065 [2]清华大学电子工程系,北京100084

出　　处：《重庆大学学报（自然科学版）》2003年第11期74-79,共6页Journal of Chongqing University

基　　金：国家自然科学基金资助项目(69831030);重庆邮电学院科技基金资助项目(A2001-33)

摘　　要：在正交频分复用(OFDM)系统中,时间及频率的偏移对系统的性能有很大影响。针对时变多径的移动通信信道,提出了基于PN序列的时域同步与频偏估计方法。在时域上,引入两段相同的PN序列作导频,通过与接收端本地PN序列相关,捕获到粗同步位置实现帧同步;利用滑动窗和最小均方差方法实现符号同步;由接收到的时域PN序列进行相关,得到频偏的粗调整量,由累积保护间隔相关方法得到细频偏量。通过仿真,给出了本方案的估计精度及适用范围,证明了它是一种实用可行方案。In orthogonal frequency division multiplexing (OFDM) systems, time offset and frequency affects its performance. A novel carrier frequency offset and timing offset detection scheme is proposed based on PN sequence, two same PN sequence pilot are inserted in Time-domain of OFDM symbols, when they are correlated with receiver PN sequence, frame synchronization can be obtained, then symbol synchronization is got basing slide windowed technique and minimum mean square error method. Depending on the two correlated peaks of PN sequences, coarse frequency offset is estimated. Basing cyclic prefix(CP) , an accumulated scheme is proposed to estimate the exactitude frequency offset. Excellent synchronization performance can be implemented in timevary mulitpaths, and these schemes are proven by simulations.

关 键 词：正交频分复用 时间同步 频率偏移 

分 类 号：TN92[电子电信—通信与信息系统]