Robust Spectrum Sensing for Noncircular Signal in Multiantenna Cognitive Receivers
Robust Spectrum Sensing for Noncircular Signal in Multiantenna Cognitive Receivers
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DOI：
10.1109/tsp.2014.2371776
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发表时间：
2015
影响因子：
5.4
通讯作者：
Lei Huang;Yuhang Xiao;Keith Q. T. Zhang
中科院分区：
文献类型：
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作者：
Lei Huang;Yuhang Xiao;Keith Q. T. Zhang
虽然非圆（NC）信号在无线通信中经常遇到，但它们的统计特性尚未在用于频谱感测的现有技术方法中被利用。本文提出了一种改进的Hadamard（HDM）比检验算法，利用原始信号的NC特性进行频谱感知，称为NC-HDM算法。由于NC-HDM方法能够利用NC信号的全部统计特性并处理来自独立同分布（IID）噪声的偏差，因此其在检测精度和/或鲁棒性方面上级现有技术的算法。此外，对NC-HDM方法进行了性能分析，包括不变性、虚警概率和检测概率。也就是说，采用矩匹配盒的卡方近似，可以确定虚警概率。由于NC-HDM检验统计量在信号缺失假设下的精确矩可以确定，并且所有矩都已匹配，因此导出的虚警概率非常准确，从而导致理论决策阈值的简单而精确的计算。另一方面，由于NC-HDM检验统计量在信号存在假设下的前两个精确矩可以精确计算，因此基于矩匹配Beta近似的检测概率是相当准确的。数值结果表明，NC-HDM方法的优越性，并验证我们的理论计算。
Although noncircular (NC) signals are frequently encountered in wireless communications, their statistical property has not yet been utilized in state-of-the-art methods for spectrum sensing. In this paper, a variant of Hadamard (HDM) ratio test is devised to exploit the NC property of the primary signals for spectrum sensing, which is named the NC-HDM algorithm. As the NC-HDM approach is able to exploit full statistical property of the NC signals and handle deviations from independent and identically distributed (IID) noise, it is superior to the state-of-the-art algorithms in detection accuracy and/or robustness. Moreover, performance analysis is conducted for the NC-HDM approach, including the invariant property, false-alarm probability and detection probability. That is, employing the moment-matching Box's Chi-square approximation, the false-alarm probability can be determined. Since the exact moments of the NC-HDM test statistic under the signal-absence hypothesis can be determined and all moments have been matched, the derived false-alarm probability is very accurate, leading to simple and precise computation of the theoretical decision threshold. On the other hand, as the first two exact moments of the NC-HDM test statistic under the signal-presence hypothesis can be precisely calculated, the detection probability based on moment-matching Beta approximation is quite accurate. Numerical results are included to demonstrate the superiority of the NC-HDM approach and validate our theoretical calculations.