College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China.
Wuhan Maritime Communication Research Institute, Wuhan 430200, China.
Sensors (Basel). 2023 Mar 16;23(6):3168. doi: 10.3390/s23063168.
Since orthogonal frequency division multiplexing (OFDM) systems are very susceptible to symbol timing offset (STO) and carrier frequency offset (CFO), which cause inter-symbol interference (ISI) and inter-carrier interference (ICI), accurate STO and CFO estimations are very important. In this study, first, a new preamble structure based on the Zadoff-Chu (ZC) sequences was designed. On this basis, we proposed a new timing synchronization algorithm, called the continuous correlation peak detection (CCPD) algorithm, and its improved algorithm: the accumulated correlation peak detection (ACPD) algorithm. Next, the correlation peaks that were obtained during the timing synchronization were used for the frequency offset estimation. For this, the quadratic interpolation algorithm was adopted as the frequency offset estimation algorithm, which was better than the fast Fourier transform (FFT) algorithm. The simulation results showed that when the correct timing probability reached 100%, under the parameters of = 8 and = 512, the performance of the CCPD algorithm was 4 dB higher than that of Du's algorithm, and that of the ACPD algorithm was 7 dB. Under the same parameters, the quadratic interpolation algorithm also had a great performance improvement in both small and large frequency offsets, when compared with the FFT algorithm.
由于正交频分复用（OFDM）系统对符号定时偏移（STO）和载波频率偏移（CFO）非常敏感，这会导致符号间干扰（ISI）和载波间干扰（ICI），因此准确估计 STO 和 CFO 非常重要。在本研究中，首先设计了一种基于 Zadoff-Chu（ZC）序列的新前导结构。在此基础上，我们提出了一种新的定时同步算法，称为连续相关峰值检测（CCPD）算法及其改进算法：累积相关峰值检测（ACPD）算法。接下来，在定时同步过程中获得的相关峰值用于频率偏移估计。为此，采用二次插值算法作为频率偏移估计算法，优于快速傅里叶变换（FFT）算法。仿真结果表明，当正确定时概率达到 100%时，在参数 = 8 和 = 512 的情况下，CCPD 算法的性能比 Du 算法高 4dB，ACPD 算法的性能高 7dB。在相同参数下，二次插值算法在小频偏和大频偏下均比 FFT 算法有很大的性能提升。
