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In this letter, a power-control scheme for maximum sum-rate is proposed for the fading multiple access channels by considering the presence of primary users. Both the average transmit-power constraints and the peak interference-temperature constraints are considered. The interference caused by cognitive users must be under a pre-specified threshold for protecting primary users. The power-control optimization...
In this paper, we investigated the end-to-end throughput of a chain in Cognitive Radio Networks (CRNs). We found that, the end-to-end throughput is dependant on both the primary usage patterns and the transmission scheduling scheme being used. In addition, to increase the end-to-end throughput of a Cognitive Radio (CR) chain, the scheduling scheme should be adjusted according to the primary usage...
In cognitive radio networks, the limitation of control channel bandwidth is a challenge of cooperative spectrum sensing when the number of cognitive users becomes very large. Cluster- based architecture is applied for cooperative sensing to avoid the congestion on control channel and reduce the sensing delay. In this paper, we propose a cluster-based cooperative spectrum sensing scheme to improve...
Cognitive radio and OFDMA attracts a lot of attentions in academic and industry fields. In this paper, the asymptotic performance of an uplink radio resource allocation scheme is investigated for OFDMA-based cognitive radio networks. Considering the characteristics of cognitive radio and OFDMA, in the uplink subcarrier allocation algorithm, the subcarriers are allocated to the users with the best...
Routing in cognitive radio networks (CRN) should consider both the end-to-end performances and the interference to the primary systems. In this paper, we categorized routing metrics into three types and derived new metrics of each type. Firstly, by considering the primary usage pattern and maximum CR link hold-time, we derived three new metrics MET, RH and METRH to capture different end-to-end performances...
Cognitive radio makes it possible for an unlicensed user to access a spectrum unoccupied by the licensed user. In this paper, the resource allocation is investigated for OFDMA-based cognitive radio networks. Considering the characteristics of cognitive radio and OFDMA, an improved water-filling power allocation scheme is proposed under the interference temperature constraints. Based on the improved...
Cognitive radio makes it possible for an unlicensed user to access a spectrum unoccupied by licensed users. Efficient subcarricr and power allocation algorithm in CR networks is a challenging problem, especially for uplink. In this paper, an efficient multiuser water-filling algorithm is proposed under the interference temperature constraints. L'sing this algorithm, subcarriers are allocated to the...
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