Novel Pilot-Assisted Spectrum Sensing for OFDM Systems by Exploiting Statistical Difference Between Subcarriers
Novel Pilot-Assisted Spectrum Sensing for OFDM Systems by Exploiting Statistical Difference Between Subcarriers
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DOI：
10.1109/tcomm.2013.020813.120323
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发表时间：
2013-02
影响因子：
8.3
通讯作者：
Zhengwei Lu;Y. Ma;Parisa Cheraghi;R. Tafazolli
中科院分区：
文献类型：
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作者：
Zhengwei Lu;Y. Ma;Parisa Cheraghi;R. Tafazolli
本文提出了一种用于正交频分复用（OFDM）系统的新型导频辅助频谱感知技术。主要思想是基于承载导频或有效负载数据的子载波具有不同的一阶和二阶统计特性的物理性质。当感兴趣的频谱未被占用时，这些差异就会消失。因此，频谱可用性的决策可以基于这些差异来形成，这可以通过频域差分运算来探索。由于采用了差分运算，所提出的技术对由不完善的硬件引起的噪声功率不确定性问题的敏感性较低。所提出技术的性能根据误报概率（PFA）和检测概率（PD）进行分析表述。进行计算机模拟以详细说明分析结果。结果表明，所提出的基于二阶统计的技术优于传统导频辅助技术高达 7 dB。此外，结果表明，对于小的归一化多普勒频移（≤ 0.013），基于一阶统计的所提出的技术优于基于二阶统计的所提出的技术。然而，基于二阶统计的所提出的技术为较大的归一化多普勒频移提供了更好的性能。
This paper presents a novel pilot-assisted spectrum sensing technique for orthogonal frequency-division multiplexing (OFDM) systems. The main idea is based upon the physical nature that subcarriers carrying pilots or payload data have different first-order and second-order statistical properties. These differences vanish when the spectrum of interest is unoccupied. Therefore, the decision of spectrum availability can be formed based upon these differences, which can be explored through employment of frequency-domain differential operations. Thanks to the differential operations, the proposed technique has less sensitivity of the noise power uncertainty problem caused by imperfect hardware. Performance of the proposed technique is analytically formulated in terms of probability of false alarm (PFA) and probability of detection (PD). Computer simulations are carried out to elaborate the analytical results. It is shown that the second-order statistics based proposed technique outperforms the conventional pilot-assisted technique up to 7 dB. Moreover, it is shown that the first-order statistics based proposed technique outperforms the second-order statistics based proposed technique for small normalized Doppler shifts (≤ 0.013). However, the second-order statistics based proposed technique offers better performance for larger normalized Doppler shifts.