In cooperative spectrum sensing, more secondary user makes more opportunity for detecting the vacant spectrums, which resulting the spectrum utilization improved, however much bandwidth would be occupied for sending t...In cooperative spectrum sensing, more secondary user makes more opportunity for detecting the vacant spectrums, which resulting the spectrum utilization improved, however much bandwidth would be occupied for sending the local observation results, inducing the reduced secondary throughput. In this paper, an adaptive algorithm for selecting detection threshold was proposed, where the maximized secondary throughput can always be achieved while assuring sufficient protection to primary user, regardless of the number of sensing users in cognitive radio networks. Theoretical analysis and simulation results validate the proposed scheme.展开更多
A threshold setting scheme is proposed based on the resource management and limited feedback theory in multiuser orthogonal frequency division multiplexing （OFDM） systems. In adaptive resource allocation, the factor...A threshold setting scheme is proposed based on the resource management and limited feedback theory in multiuser orthogonal frequency division multiplexing （OFDM） systems. In adaptive resource allocation, the factors denoting the quality of service （QoS） and fairness are both considered as the user weight. From the aspect of feedback outage probability, the proposed algorithm sets the threshold for each user related to its weight, which brings enough feedback to the user with greater weight. Analysis and simulation results show that, compared with the threshold ignoring weights, the proposed scheme has much lower feedback load while with better QoS.展开更多
Considering the joint channel estimation and data detection in time-varying orthogonal frequency division multiplexing （OFDM） and addressing transmission performance degradation induced by the severe inter-carrier i...Considering the joint channel estimation and data detection in time-varying orthogonal frequency division multiplexing （OFDM） and addressing transmission performance degradation induced by the severe inter-carrier interference （ICI） at very high speed, a new progressive iterative channel estimation scheme is proposed. To alleviate the error propagation of the inaccurate data due to ICI, the measurement subcarriers in the Kalman filter is designed to be extended from pilots subcarriers to all the subcarriers progressively through the iterations. Furthermore, in iteration process, the interference of the non-pilot data to the measurement subcarriers is considered to be part of noise in the modified Kalman filter, which improves the estimation accuracy. Simulation indicates that the proposed scheme improves the performance in fast time-varying situation.展开更多
基金supported by The National Natural Science Foundation of China (60872149,60672132)
文摘In cooperative spectrum sensing, more secondary user makes more opportunity for detecting the vacant spectrums, which resulting the spectrum utilization improved, however much bandwidth would be occupied for sending the local observation results, inducing the reduced secondary throughput. In this paper, an adaptive algorithm for selecting detection threshold was proposed, where the maximized secondary throughput can always be achieved while assuring sufficient protection to primary user, regardless of the number of sensing users in cognitive radio networks. Theoretical analysis and simulation results validate the proposed scheme.
基金supported by the National Natural Science Foundation of China(60872149)
文摘A threshold setting scheme is proposed based on the resource management and limited feedback theory in multiuser orthogonal frequency division multiplexing （OFDM） systems. In adaptive resource allocation, the factors denoting the quality of service （QoS） and fairness are both considered as the user weight. From the aspect of feedback outage probability, the proposed algorithm sets the threshold for each user related to its weight, which brings enough feedback to the user with greater weight. Analysis and simulation results show that, compared with the threshold ignoring weights, the proposed scheme has much lower feedback load while with better QoS.
基金supported in part by the National Natural Science Foundation of China (61372089, 61201198)
文摘Considering the joint channel estimation and data detection in time-varying orthogonal frequency division multiplexing （OFDM） and addressing transmission performance degradation induced by the severe inter-carrier interference （ICI） at very high speed, a new progressive iterative channel estimation scheme is proposed. To alleviate the error propagation of the inaccurate data due to ICI, the measurement subcarriers in the Kalman filter is designed to be extended from pilots subcarriers to all the subcarriers progressively through the iterations. Furthermore, in iteration process, the interference of the non-pilot data to the measurement subcarriers is considered to be part of noise in the modified Kalman filter, which improves the estimation accuracy. Simulation indicates that the proposed scheme improves the performance in fast time-varying situation.
