Noise uncertainty can severely deteriorate a primary user (PU) detector’s sensing performance, so robustness against the noise uncertainty is of fundamental significance in cognitive radio networks. In this paper, we investigate robust detection schemes in the presence of noise uncertainty for multiple-input multiple-output (MIMO) based cognitive radio wireless sensor networks (CR-WSN) with multiple spectrum sensing scenarios. In practice, it is very seldom that accurate statistical characterization of noise is known a priori. In this context, we propose the generalized likelihood ratio test (GLRT) paradigm and estimator-correlator based optimal detectors to sense the unoccupied primary bands in the presence of noise uncertainty. First, we compute the estimator-correlator based detector (ECD) and generalized likelihood detector (GLD) for known noise uncertainty statistics. Next, a composite hypothesis based detector (CHD) is proposed using the GLRT framework for unknown noise uncertainty statistics. The proposed detection schemes provide robustness against uncertainty in the available noise power estimates using a finite number of observations (i.e., fast spectrum sensing) and particularly in critical areas of low Signal-to-Noise Ratio (SNR). Theoretical analysis is performed based on statistical theory. Closed-form expressions for detection and false-alarm probability, and analytic decision threshold are derived to demonstrate spectrum sensing performance using receiver operating characteristic (ROC) curves. Simulation results validate that proposed PU detection schemes are robust and achieve an improved sensing performance when there is noise uncertainty and corroborate our theoretical findings.

噪声不确定性会严重恶化主要用户（PU）检测器的感测性能，因此，针对噪声不确定性的鲁棒性在认知无线电网络中具有根本意义。在本文中，我们研究了在存在噪声不确定性的情况下，针对具有多频谱感测方案的，基于多输入多输出（MIMO）的认知无线电无线传感器网络（CR-WSN）的鲁棒检测方案。实际上，很少先验地知道噪声的精确统计特征。在这种情况下，我们提出了基于广义似然比测试（GLRT）范例和基于估计器相关器的最佳检测器，以在存在噪声不确定性的情况下感测未占用的主频带。第一的，我们针对已知的噪声不确定性统计数据计算基于估计器-相关器的检测器（ECD）和广义似然检测器（GLD）。接下来，针对未知噪声不确定性统计数据，使用GLRT框架提出了一种基于复合假设的检测器（CHD）。所提出的检测方案利用有限数量的观察（即，快速频谱感测），尤其是在低信噪比（SNR）的关键区域中，提供了针对可用噪声功率估计中的不确定性的鲁棒性。理论分析是基于统计理论进行的。得出用于检测和错误警报概率的闭式表达式，以及解析决策阈值，以使用接收器工作特性（ROC）曲线演示频谱感测性能。