Efficient OFDM Symbol Timing Estimator Using Power Difference Measurements
Efficient OFDM Symbol Timing Estimator Using Power Difference Measurements
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DOI：
10.1109/tvt.2011.2177530
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发表时间：
2012-02
影响因子：
6.8
通讯作者：
A. Al-Dweik;S. Younis;A. Hazmi;C. Tsimenidis;B. Sharif
中科院分区：
文献类型：
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作者：
A. Al-Dweik;S. Younis;A. Hazmi;C. Tsimenidis;B. Sharif
提出了一种适用于恒模星座正交频分复用（OFDM）系统的符号定时盲估计算法。所提出的技术被设计为通过最小化在两个连续的OFDM符号上具有相似索引的子载波之间的功率差来估计符号定时偏移，基于信道随时间缓慢变化的假设。所提出的功率差估计器（PDE）是完全盲的，因为它不需要有关信道或传输数据的先验信息。蒙特卡罗模拟被用来评估PDE性能的正确定时估计Plock-in的概率。此外，我们提出了一个新的性能指标表示为偏离安全区域（DSR）。仿真结果表明，PDE在严重的频率选择性衰落信道中表现良好，优于其他考虑的估计。通过引入低成本的估计器来提供初始的粗略定时信息，可以显著降低PDE的复杂度。建议PDE实现使用前馈和早迟门（ELG）配置。新的PDE-ELG不遭受自噪声问题固有的其他ELG估计在文献中报道。
This paper presents an efficient blind symbol timing estimation scheme for orthogonal frequency-division multiplexing (OFDM) systems with constant modulus constellation. The proposed technique is designed to estimate symbol timing offsets by minimizing the power difference between subcarriers with similar indices over two consecutive OFDM symbols based on the assumption that the channel slowly changes over time. The proposed power difference estimator (PDE) is totally blind because it requires no prior information about the channel or the transmitted data. Monte Carlo simulation is used to assess the PDE performance in terms of the probability of correct timing estimate Plock-in. Moreover, we propose a new performance metric denoted as the deviation from safe region (DSR). Simulation results have demonstrated that the PDE performs well in severe frequency-selective fading channels and outperforms the other considered estimators. The complexity of the PDE can be significantly reduced by incorporating a low-cost estimator to provide initial coarse timing information. The proposed PDE is realized using feedforward and early-late gate (ELG) configurations. The new PDE-ELG does not suffer from the self-noise problem inherent in other ELG estimators reported in the literature.