One of the main challenges in implementing spectrum sensing techniques concerns the system robustness against noise power uncertainties. In this paper, a performance analysis of energy detection-based cognitive radio system is carried out assuming absence/presence of noise uncertainty for the sensing channel modeled by the α-η-κ-µ fading channel. The detection capacity of spectral sensing over several representative scenarios is analyzed with the theoretical results validated through Monte Carlo simulations. The results show that the performance of the spectral sensing technique is drastically affected by the noise uncertainty as well as by the channel conditions described the fading parameters α, η, κ, and µ. Both the ratio of the power of the dominant component to the power of the scattered and quadrature scattering signal and the clustering imbalance have a smaller impact on the overall performance. The offered results are especially useful in assessing the effect of fading in energy detector-based cognitive radio communication systems. Index Terms-Spectrum sensing, energy detector, α-η-κ-µ fading model, noise uncertainty. I. INTRODUCTION W ITH the exponential increase in demand for mobile communications services, the electromagnetic spectrum of radio frequencies tends to become increasingly congested. Regulatory agencies have used fixed band allocation policy, where the resource is allocated by type of service and users acquire the right to exploit certain bandwidth. This management policy results in underutilization of the resource, since the holder of the right to use a particular band may not do it all time and in all area where the service is offered. Consequently, there is a contradictory scenario in which the resource is at the same time scarce and underutilized, generating a great challenge for future mobile technologies, for example 5G and beyond. In this context, the concept of cognitive radio (CR) [2] arises, which proposes, among other functionalities, the opportunistic use of the spectrum. To perform this task, CR carries out the spectral sensing [2], which consists of