Blind estimation of symbol timing and carrier frequency offset in wireless OFDM systems
Blind estimation of symbol timing and carrier frequency offset in wireless OFDM systems
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DOI：
10.1109/26.930629
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发表时间：
2001-06
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影响因子：
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通讯作者：
H. Bölcskei
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作者：
H. Bölcskei
正交频分复用（OFDM）系统对同步误差高度敏感。提出了一种无线OFDM系统中符号定时和载波频偏的盲估计算法。所提出的估计器是Gini-Giannakis的扩展（参见IEEE Trans. Commun.，Vol.46，p.400-411，1998）用于单载波系统的估计器。它利用OFDM信号的循环平稳性，仅依赖于二阶统计量。我们的方法可以应用于脉冲成形OFDM系统与任意的时间-频率保护区，OFDM基于偏移正交幅度调制，和双正交频分复用系统。我们还提出了使用不同的子载波发射功率（子载波加权）和周期性的发射机预编码，以实现OFDM信号的整个带宽的载波频率采集范围，和任意长度的符号定时采集范围。最后，我们提供了模拟结果证明新的估计的性能。
Orthogonal frequency-division multiplexing (OFDM) systems are highly sensitive to synchronization errors. We introduce an algorithm for the blind estimation of symbol timing and carrier frequency offset in wireless OFDM systems. The proposed estimator is an extension of the Gini-Giannakis (see IEEE Trans. Commun., vol.46, p.400-411, 1998) estimator for single-carrier systems. It exploits the cyclostationarity of OFDM signals and relies on second-order statistics only. Our method can be applied to pulse shaping OFDM systems with arbitrary time-frequency guard regions, OFDM based on offset quadrature amplitude modulation, and biorthogonal frequency-division multiplexing systems. We furthermore propose the use of different subcarrier transmit powers (subcarrier weighting) and periodic transmitter precoding to achieve a carrier frequency acquisition range of the entire bandwidth of the OFDM signal, and a symbol timing acquisition range of arbitrary length. Finally, we provide simulation results demonstrating the performance of the new estimator.