中文摘要：

将中继协作技术用于认知无线电网络可有效对抗信道衰落,提高频谱利用率,然而如何选择中继协助源节点传输信息是一个亟待解决的问题。该文根据多中继协作时目的节点信噪比的一阶偏导数特征,定义了中继协作效率,设计了基于协作效率的迭代中继选择方案。考虑到认知中继网络的非集中式结构,该文将虚拟计时器引入中继节点,提出了基于迭代中继选择方案的分布式算法,通过各中继基于协作效率的虚拟倒计时及信息交互实现了分布式迭代中继选择。复杂度分析和数值仿真结果表明,该算法复杂度较低,且性能接近最优解。

英文摘要：

Cognitive relay networks can mitigate channel fading and enhance the spectrum utilization effectively.However,relay selection is a problem of great importance to be solved.According to the features of first order partial derivative of the Signal-to-Noise Ratio（SNR） at destination node,this paper defines the cooperative efficiency and designs an iterative relay selection scheme.Considering the decentralized structure of cognitive relay networks,this paper introduces virtual timer into relay nodes and proposes the distributed algorithm based on the iterative relay selection scheme.In this algorithm,the distributed multiple relay selection is implemented through the virtual timer at individual relays and the exchange of pertinent information.The asymptotic complexity analysis and numerical simulation results prove that the proposed scheme achieves near-optimal performance with low computing efforts and communication overheads.