计算机应用 ›› 2015, Vol. 35 ›› Issue (2): 354-357.DOI: 10.11772/j.issn.1001-9081.2015.02.0354

• 网络与通信 • 上一篇    下一篇

基于最小特征值分布的频谱感知算法

杨智, 徐家品   

  1. 四川大学 电子信息学院, 成都 610065
  • 收稿日期:2014-08-25 修回日期:2014-11-13 出版日期:2015-02-10 发布日期:2015-02-12
  • 通讯作者: 徐家品
  • 作者简介:杨智(1987-),男,湖南岳阳人,硕士,主要研究方向:通信与信息系统; 徐家品(1957-),男,四川成都人,教授,主要研究方向:通信与信息系统。

Spectrum sensing algorithm based on least eigenvalue distribution

YANG Zhi, XU Jiapin   

  1. College of Electronics and Information Engineering, Sichuan University, Chengdu Sichuan 610065, China
  • Received:2014-08-25 Revised:2014-11-13 Online:2015-02-10 Published:2015-02-12

摘要:

现有的频谱感知算法中,能量检测容易实现,但检测性能依赖噪声功率。基于随机矩阵理论的频谱感知算法巧妙地规避了噪声不确定性对检测性能带来的影响,但大都采用的是最大特征值的近似分布规律,所得到阈值表达式的精度有待进一步提高。针对上述问题,通过利用随机矩阵理论的最新研究成果,提出一种基于接收信号样本协方差矩阵最小特征值分布的频谱感知算法。最小特征值的分布函数不基于渐近假设,更加符合实际的通信情境。推导所得的阈值表达式是虚警概率的函数,在小样本情况下,对它的有效性和优越性进行了分析与验证。根据单一变量原则,分别在低样本点、低协作用户数、低信噪比和低虚警概率条件下对提出算法与最大最小特征值算法的检测性能进行了仿真比较,检测概率最多可以提高0.2左右。结果表明,该算法能够显著改善系统的检测性能。

关键词: 频谱感知, 随机矩阵理论, 阈值表达式, 样本协方差矩阵, 最小特征值

Abstract:

Among the existing spectrum sensing algorithms, energy detection can be implemented easily, but its detection performance depends on noise power. Spectrum sensing algorithms based on random matrix theory can skillfully avoid the influence of noise uncertainty on detection performance, but most of them make use of approximate distribution of the largest eigenvalue. The accuracy of threshold expression derived from it needs to be further improved. Aiming to above problems, by using the latest research results about random matrix theory, a spectrum sensing algorithm based on distribution of the least eigenvalue of sample covariance matrix of received signals was proposed. Cumulative distribution function of the least eigenvalue is not based on asymptotical assumptions, which is more suitable for realistic communication scenarios. The threshold expression derived from it was a function of false alarm probability, whose effectiveness and superiority were analyzed and verified with few samples. Simulations complied with single variable principle were conducted under the situation of few samples, few collaborative users, low signal to noise ratio and low false alarm probability, in comparison with classic maximum-minimum eigenvalue algorithm. Detection probability of the proposed algorithm was increased by 0.2 or so. The results show that the proposed algorithm can significantly improve the detection performance of system.

Key words: spectrum sensing, random matrix theory, threshold expression, sample covariance matrix, least eigenvalue

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