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Joint Optimization of Cooperative Threshold and Power Based on Cooperation Level in Cognitive Radio Networks |
Zhang Wei-liang Zheng Bao-yu Yue Wen-jing |
Institute of Signal Processing and Transmission,Nanjing University of Posts and Telecommunications, Nanjing 210003, China |
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Abstract Cooperative transmission for cognitive radio networks not only enhances the anti-fading capability of the system, but also improves the bandwidth efficiency. But it’s really a worth considering issue when the relay node should assit the source node to transmit information. This paper proposes a cooperative guideline based on cooperative level. Firstly the notion of cooperative level is defined, then the expressions of system bandwidth utilization and the average symbol error rate are deduced, finally the system performance function is got through the compromise between the coorperative thresholds and power ratio. This paper also employs particle swarm optimization algorithm to solve optimal cooperative threshold and optimal power ratio. The simulation results verify the performance of the proposed scheme and show that good link state from source node to destination node and cooperative transmission by the relay node are both useful for optimizing the system performance.
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Received: 21 March 2011
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Corresponding Authors:
Zhang Wei-liang
E-mail: nupt.wlzhang@163.com
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