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In Cognitive Radio (CR) networks, multiple secondary network users (SUs) attempt to communicate over wide potential spectrum without causing significant interference to the Primary Users (PUs). A spectrum sensing algorithm is a critical component of any sensing strategy. Performance of conventional spectrum detection methods is severely limited when the average SNR of the fading channel between the...
Spectrum sensing is one of the major elements of cognitive radio applications. A single secondary user (SU) usually cannot provide robust sensing capability due to channel effects. In order to overcome this problem, cooperative spectrum sensing techniques have been proposed. Because conventional cooperative spectrum sensing schemes assumed that all sensing nodes have the same sensing reliability,...
We consider cooperative spectrum sensing for cognitive radios. We develop an energy efficient detector with low detection delay using sequential hypothesis testing. Sequential Probability Ratio Test (SPRT) is used at both the local nodes and the fusion center. We also analyse the performance of this algorithm and compare with the simulations. Modelling uncertainties in the distribution parameters...
In this letter, we propose two relay selection schemes in cognitive relay networks. According to the proposed schemes, the number of relays involved in the opportunistic relaying is determined by the partial channel state information (CSI) of primary user link and partial CSI between the relays and the primary user receiver, so as to maintain the primary user's outage probability below a predetermined...
Cooperative spectrum sensing can improve the detection reliability in cognitive radio network. How to report the local sensing results to the fusion center has not aroused much interest. Since OFDM has been widely recognized as a promising candidate for cognitive radio in opportunistic spectrum access scenarios, a OFDMA-based sensing reporting scheme is designed. Correspondingly, several fusion rules...
In this paper, the analysis model which suites to Cognitive Radio (CR) communication together with amplify-and-forward cooperative communication systems where cognitive users can act as cooperative diversity relays to the licensed users based on average Channel State Information (CSI) is presented. Firstly, the model of the cooperative and cognitive radio system is given. Then, the transmitting protocols...
Cognitive radio design aims to increase spectrum utilization by allowing the secondary users (SUs) to coexist with the primary users (PUs) as long as the interference caused by the SUs to each PU is properly regulated. At the SU, channel state information (CSI) between its transmitter and the PU receiver is used to calculate the maximum allowable SU transmit power to limit the interference. We assume...
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