利用秩和检验的多天线协作频谱感知

Cooperative Spectrum Sensing Using Rank-sum Test for Multi-antenna Cognitive Radio

高效稳定的频谱感知是认知无线电系统的关键环节。传统的能量检测算法受噪声不确定性影响,而协方差矩阵类算法在天线相关性低时性能较差。针对上述缺陷,利用秩来衡量由信道衰落导致的同一感知时刻不同天线上的信号功率差异,提出通过构建秩和统计量来实现频谱感知的算法。另外,推导了所提算法判决门限的理论表达式,结果显示其不受采样点数影响,因此当采样点数变化时无需重新设置门限。理论分析和仿真表明所提算法不受噪声不确定度的影响,并且在低天线相关性时可以保持良好的性能。

Spectrum sensing is a fundamental component in cognitive radio. To overcome the defects that energy detection is affected by noise uncertainty and the performance of existing cooperative spectrum sens-ing algorithms on covariance matrix degrades in low antenna correlation scenes, the rank is used to evaluate the power of different antennas,which is caused by channel fading. In this paper, a spectrum sensing algo-rithm based on rank-sum test is presented. The theoretical expression of decision threshold is also derived, which shows that the decision threshold has no relationship with the sample number. As a result, the threshold does not need to be reset when the sample number changes. Theoretical analysis and simulation show that the performance of the proposed algorithm is robust to noise uncertainty and it has good perform-ance with low antenna correlation.