大频偏低信噪比条件下OFDM系统中的符号定时估计

Symbol Timing Estimation under Large Frequency Offset and Low Signal to Noise Ratio in OFDM Systems

符号定时估计是OFDM系统中的关键问题之一,该文就此问题提出了一种新的基于训练符号的定时估计算法。研究表明,新算法的性能基本不受载波频偏的影响,且具有很强的抗噪特性。通过采用这种算法可将定时误差缩小到只有抽样时间间隔的一半。并且,还可利用这个频域训练符号来进行载波频偏的估计,从而只需一个训练符号就能完成符号定时和载波频偏的联合捕获。

Symbol timing estimation is one of key problems in OFDM systems. In this paper a new symbol timing estimation algorithm based on a training symbol is proposed. The study shows that the new algorithm is not affected by carrier frequency offset basically, and has strong characteristic of resisting noise. Through adopting this algorithm the timing error is shortened to a half of the sample time interval. Furthermore the frequency-domain training symbol can be used to estimate carrier frequency offset, so only a training symbol is needed to complete joint acquisition of symbol timing and carrier frequency offset.