| 摘要: |
| 针对正交频分复用（OFDM）系统对同步错误率和频率偏移敏感的问题，提出了一种叠加共轭对称训练序列的OFDM系统时间和频率同步方法。该同步方法将快速傅里叶逆变换（IFFT）调制后的序列构成具有共轭对称特性的训练序列，并叠加到OFDM数据符号上；在接收端，利用叠加训练序列和融合循环前缀信息来获取OFDM系统同步信息。理论分析和仿真表明：在信噪比为5 dB时，该同步算法定时同步正确概率已接近100%；在信噪比为4 dB时，频偏估计精度可以达到10-4；该同步算法不仅具有更好的同步性能，而且节省系统的有效带宽以及降低系统的计算法复杂度。 |
| 关键词: OFDM 时频同步 叠加训练序列 共轭对称 频偏估计 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（61310306022）；四川省“千人计划”引进人才资金资助项目；四川省科技支撑计划资助项目（2012FZ0021）；西南石油大学油气信号检测与信息处理青年科研创新培育团队资金资助项目（2013XJZT007） |
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| Timing and frequency synchronization method for OFDM system with superimposed conjugate symmetric training sequences |
| LUO Ren-ze,YANG Jiao,GE Yong-hua |
| () |
| Abstract: |
| The orthogonal frequency-division multiplexing(OFDM) system is sensitive to synchronization error rate and frequency offset.This paper proposes a timing and frequency synchronization method with the superimposed conjugate symmetric training sequences to solve the problem.This synchronization method utilizes the inverse fast Fourier transform(IFFT) modulated sequences to construct training sequences with conjugate symmetric properties.Then the training sequences are superimposed on OFDM data symbols.At the receiver,the synchronization information is obtained by superimposed training sequences and combining the information of cyclic prefix.Theoretical analysis and simulation show that:with signal-to-noise ratio(SNR) 5 dB,the probability of correct timing synchronization achieves nearly 100%,and with SNR 4 dB,the precision of the frequency offset estimation can be as high as 10-4;this synchronization algorithm has better synchronization performance,at the same time,it saves system bandwidth effectively and reduces computational complexity. |
| Key words: orthogonal frequency-division multiplexing(OFDM) timing and frequency synchronization superimposed training sequence conjugate symmetry frequency offset estimation |
