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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. However, detection performance in practice is often compromised with multipath fading, shadowing and receiver uncertainty issues. To mitigate the impact of these issues,(More)
—In this paper, the problem of resource allocation optimization is studied for a single-cell multiuser cognitive radio network in the presence of primary user networks. The spectral access of the cognitive radio network is based on Orthogonal Frequency Division Multiple Access (OFDMA). A joint band-width and power allocation is performed so that users' rate(More)
—In cognitive radio networks, spectrum sensing is a fundamental function for detecting the presence of primary users in licensed frequency bands. Due to multipath fading and shadowing, the performance of detection may be considerably compromised. To improve the detection probability, cooperative sensing is an effective approach for secondary users to(More)
—A constantly available control channel facilitates control message exchange and spectrum coordination in cognitive radio (CR) ad hoc networks. When a dedicated control channel is unavailable, a control channel must be dynamically allocated in licensed channels and vacated for the presence of primary users (PUs). As a result, the establishment of such a(More)
Spectrum sensing is a fundamental function in cognitive radio networks for detecting the presence of primary users in licensed bands. The detection performance may be considerably compromised due to multipath fading and shadowing. To resolve this issue, cooperative sensing is an effective approach to combat channel impairments by cooperation of secondary(More)
—Control channel jamming is a severe security problem in wireless networks. This results from the fact that the attackers can effectively launch the denial of service attacks by jamming the control channels. Traditional approaches to combating this problem such as channel hopping sequences may not be the secure solution against intelligent attackers because(More)
In this paper, the energy efficiency of cooperative sensing in cognitive radio networks is investigated. In cooperative sensing, more energy is consumed in sensing the channel and reporting the results to the fusion detector. To address this issue a very innovative design called External Sensing Energy Efficient technique is proposed in this literature.(More)