Spectrum sensing, i.e., detecting the presence of primary users in a licensed spectrum, is a fundamental problem in cognitive radio. Since the statistical covariances of the received signal and noise are usually different, they can be used to differentiate the case where the primary user’s signal is present from the case where there is only
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Spectrum sensing, i.e., detecting the presence of primary users in a licensed spectrum, is a fundamental problem in cognitive radio. Since the statistical covariances of the received signal and noise are usually different, they can be used to differentiate the case where the primary user’s signal is present from the case where there is only
(Read More…)
By exploiting the existing wireless spectrum opportunistically, cognitive radio technology is developed to solve current wireless network problems resulting from the limited available spectrum and the inefficiency in spectrum usage. A cognitive radio (CR) is designed to be aware of and sensitive to the changes in its surrounding, which makes spectrum sensing an important requirement
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With the rapid development of wireless communication technology and the lack of frequency resources, the technology of spectrum sharing becomes more and more important. Cognitive Radio is born to fulfill the needs, which can intelligently and dynamically learn the wireless network environment around and thus an unauthorized system could communicate with each other in taking
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With the rapid development of wireless communication technology and the lack of frequency resources, the technology of spectrum sharing becomes more and more important. Cognitive Radio is born to fulfill the needs, which can intelligently and dynamically learn the wireless network environment around and thus an unauthorized system could communicate with each other in taking
(Read More…)
With the rapid development of computer technology, semiconductor technology and mobile communication technology, the focus of wireless communication services has transferred on the services that need broadband and high speed download, and it made that spectrum resource scarcity issues became more serious. Under the spectrum fixed allocation system, the utilization of most spectrum resources is
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With the rapid development of computer technology, semiconductor technology and mobile communication technology, the focus of wireless communication services has transferred on the services that need broadband and high speed download, and it made that spectrum resource scarcity issues became more serious. Under the spectrum fixed allocation system, the utilization of most spectrum resources is
(Read More…)
With increasing demand for high-speed data transmission in wireless communications, new chanlleges, such as effectively use of the spectrum resource, generated. At present, the spectrum resource has become ever more scarce, because of the allocation policy is not reasonable and the communications users increase. Cognitive Radio (CR) technique is considered as one of the effective
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Without interfering with the norm al communication of authorized users, Cognitive radio(CR) improves the spectrum resource utilization ratio, and reduces the cost of spectrum resources.This thesis mainly focused on cyclostationary based technology in spectrum sensing of CR. Diff erent characteristic of spectrum sensing methods were summarized in the paper a nd cyclostationary base d spectrum
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Nowadays, the radio spectrum was allocated for use primarily by the state, but in practice many assigned bands are underutilized in most cases, and this made the wireless resources depleting. In recent years, the cognitive radio technology provided a new way to improve the spectrum efficiency. It can continuously perceive the changes of the external
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