A joint time and frequency synchronization method based on PN sequences for OFDM
A joint time and frequency synchronization method based on PN sequences for OFDM
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DOI：
10.1109/iccsit.2009.5234984
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发表时间：
2009-09
期刊：
影响因子：
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通讯作者：
Wei Cheng;Rui-juan Yang;Xin-yu Tuo;Zhao-yong Fan
中科院分区：
文献类型：
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作者：
Wei Cheng;Rui-juan Yang;Xin-yu Tuo;Zhao-yong Fan
与单载波系统相比，OFDM系统性能对频率偏移和定时误差敏感。本文提出了一种基于 PN 序列的 OFDM 联合时间和频率同步方法。在发射机中用PN序列和差分编码的PN序列构造一个OFDM专用训练符号，在接收机中，在频偏估计之前对训练符号进行差分译码，利用PN序列的自相关特性获得时间同步，然后用本地PN序列消除接收信号极性的影响，结合ML方法得到精细的频偏估计。在低信噪比下时间同步性能优异，最大频偏估计范围可达信号总带宽的二分之一，仿真结果表明该方法是有效的。
OFDM system performance is sensitive to frequency offset and timing error than single-carried system. In this paper, a novel joint time and frequency synchronization method is proposed based on PN sequences for OFDM. A special training symbol of OFDM is constructed with the PN sequence and the differentially coded PN sequence in the transmitter, in the receiver, the training symbol is differentially decoded to get the time synchronization with the autocorrelation property of PN sequence before the frequency offset is estimated, then it eliminates the effect of polarity of the received signal with local PN sequence to get the fine frequency offset estimation combined with ML method. The performance of time synchronization is excellent in low SNR, the maximum frequency offset estimation range can be up to one half of overall signal bandwidth, the simulation results show that the proposed method is effective.