In this paper, the performance of cognitive radio (CR) code divisionmultiple access (CDMA) networks is analyzed in the presence of receive beamforming at the base stations (BSs). More precisely, we analyze, through simulations, the performance achievable by a CR user, with and without spectrum sensing, in a three-cell scenario. Uplink communications are considered. Three different schemes for s...

HIDDEN MARKOV MODEL BASED SPECTRUM SENSING FOR COGNITIVE RADIO Thao Tran Nhu Nguyen, Ph.D. George Mason University, 2013 Dissertation Co-director: Dr. Brian L. Mark Dissertation Co-director: Dr. Yariv Ephraim Cognitive radio is an emerging technology for sensing and opportunistic spectrum access in wireless communication networks. It allows a secondary user to detect under-utilized spectrum of ...

Kernel method is a very powerful tool in machine learning. The trick of kernel has been effectively and extensively applied in many areas of machine learning, such as support vector machine (SVM) and kernel principal component analysis (kernel PCA). Kernel trick is to define a kernel function which relies on the inner-product of data in the feature space without knowing these feature space data...

There has been an exponential increase in spectrum demands due to new emerging wireless services and applications, making it harder to find unallocated spectrum bands for future usage. This potential resource scarcity is rooted at inefficient utilization of spectrum under static spectrum allocation. Therefore, a new concept of dynamic spectrum access (DSA) has been proposed to opportunistically...

Spectrum sensing is identified as one of the enabling technologies for spectrum opportunities detection in cognitive radio systems. Although the latest developments in cognitive radio regulation favor the database approach, spectrum sensing can provide reliable opportunistic spectrum access in dynamic and unpredictable environments [1]. Under these circumstances, the efficiency and reliability ...

Spectrum sensing is a key function of cognitive radio to prevent the harmful interference with licensed users and identify the available spectrum for improving the spectrum’s utilization. Various methods for spectrum sensing control, such as deciding which sensors should perform sensing simultaneously and finding the appropriate trade-off between probability of misdetection and false alarm rate...

The IEEE is developing a standard for cognitive wireless regional area networks operating in unused television channels. One of the cognitive features of this standard is spectrum sensing, which is used to identify unused television channels. This paper describes the requirements for spectrum sensing and the spectrum sensing framework. A description is given of the method used for evaluating sp...

Cognitive Radio (CR) is a radio communications and networking technology that has recently attracted considerable interest from academia as well as industry worldwide. It follows the design philosophy of Dynamic Spectrum Access (DSA) as opposed to a fixed spectrum allocation policy. The enabling technology for CR is spectrum sensing, which is the inference of presence/absence of primary users (...

Motivated by the compressed sensing sparse channel estimation problem, the complete channel state is sparse under the conditions of low spectral efficiency. Other than traditional method of looking for the perception of spectrum holes, this paper focus on the sparse of occupied sub-channels. Based on compressed sensing technology, a novel cooperative wideband spectrum sensing method is proposed...

The speed and accuracy of spectrum sensing techniques are essential factors in the performance of cognitive radio networks. The limitations imposed by computational complexity and a shortened monitoring time impede the success of spectrum sensing operation performed by cognitive radio nodes. Compressive sensing techniques are viewed as novel approaches to solve scalability problems in some sign...