In order to improve sensing performance when the noise variance is not known, this paper considers a so-called blind spectrum sensing technique that is based on eigenvalue models. In this paper, we employed the spiked population models in order to identify the miss detection probability. At first, we try to estimate the unknown noise variance based on the blind measurements at a secondary location. We then investigate the performance of detection, in terms of both theoretical and empirical aspects, after applying this estimated noise variance result. In addition, we study the effects of the number of SUs and the number of samples on the spectrum sensing performance. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Ⅰ. IntroductionMuch recent work has focused on eigenvalue-based spectrum sensing methods for cognitive radio networks (CRNs) [1], [2], where researchers have applied innovations from random matrix theory to calculate the probability of a false alarm as a function of a threshold. This work has also employed many kinds of test statistics, such as the ratio of the largest and the smallest eigenvalues or the ratio of the average and the smallest eigenvalues of the sample covariance matrix. Yonghong and Ying-chang's model in [2] requires a number of samples, N, and a number of secondary users (SUs), K, approaching infinity. A significant gap exists between the simulations and analytical results.Kortun et al.[1] improved the model by finding an exact threshold and an approximate closed-form performance that agreed well with the empirical results. Independently, Penna et al. [7] derived work similar to [1] and then further analyzed the probability of a miss in [10]. However, the method used in [10] still requires knowledge of noise level and the parameters of primary user (PU) signals and channels, which is impractical in CRN scenarios. To our knowledge, not much research has been carried out regarding the relationship between the threshold and the probability of a miss when using blind spectrum sensing techniques. This paper considers a novel blind spectrum sensing technique for CRNs, where we analyze a threshold with a constraint on the probability of a miss. CRNs are composed of a specific bandwidth, including multiple PUs and the number of SUs. Based on a variety of research related to the distribution of eigenvalues [3], [4], we apply the results of random matrix theory to the spectrum sensing model. In fact, the practical model is related to a finite number of samples and SUs, while these parameters are infinite in random matrix theory. Therefore, we exploit the limit distribution for approximate results in our applied spectrum sensing model. Furthermore, the observations referred to in this spectrum sensing model undergo interference with by ...