CRN中基于自适应阈值和OR-决策规则的频谱感知策略

Spectrum sensing strategy in CRN based on adaptive threshold and OR-decision rules

针对传统认知无线电网络(CRN)的频谱感知策略没有考虑噪声不确定性问题,提出一种基于噪声功率估计自适应阈值和OR-决策规则的频谱感知策略。将各接收器数据构建成一个数据矩阵,并计算矩阵的协方差矩阵;计算协方差矩阵的特征值,并根据特征值的均值来获得噪声的最大似然估计;根据估计的噪声和能量信号的检验统计量来确定决策阈值;各节点根据决策阈值作出局部决策并上传到融合中心(FC),FC利用OR-决策规则作出最终决策。实验结果表明,该方案的决策阈值能够随噪声自适应调整,有效提高了检测率,对噪声不确定性具有很好的鲁棒性。

For the issue that the traditional spectrum sensing strategy of cognitive radio network(CRN)has not considered the noise uncertainty,this paper proposed a spectrum sensing strategy based on adaptive threshold with noise power estimation and OR-decision rules.Firstly,it built the receiver data into a data matrix,and calculated the covariance matrix of the matrix.Then,it calculated the eigenvalues of the covariance matrix,and obtained the maximum likelihood estimation of the noise according to the mean value of the eigenvalues.After that,it determined the decision threshold based on the estimation of the noise and the test statistic of the energy signal.Finally,each node made local decisions based on decision thresholds and uploaded fusion center(FC),and FC made final decisions using OR-decision rules.The experimental results show that the decision threshold of the proposed scheme can be adjusted adaptively according to the noise,which can effectively improve the detection rate and is robust to the uncertainty of the noise.