主用户具有AF中继辅助的协作频谱感知及最佳用户数分析

将主用户具有放大转发（amplify-forword,AF）中继辅助的检测模型与多个感知用户进行协作频谱感知的模型相结合，得到主用户具有AF中继协作的新模型。为减少系统开销，综合参数的影响，推导出其检测概率与虚警概率表达式，并在分析报告信道衰落环境下，通过此模型的中继放大可适当缓解衰落所带来的性能损失；进一步验证最佳参与协作用户数的存在性，设计了基于用户取值区间的搜索算法，以探索中继放大增益及错误报告概率对最佳用户数的影响。通过仿真表明，该模型能有效提高检测性能，并能在给定虚警概率下最大化检测概率时，选择合适的参数对：中继放大增益和最佳参与用户数。

Performance analysis and optimal user number based on primary user cooperation with AF relay

In the paper, we combine the detection model of primary user with the help of AF relay with multiple secondary users to perform cooperative spectrum sensing. We consider the influence of some parameters to make the overhead more efficient, and analyze the relay amplification gain which can efficiently alleviate the performance loss caused by report channel fading. Moreover, we verify the existence of the optimal number of cooperative users, design the search algorithm based on the range of users, and explore the influences of the amplification gain and reporting error probability on the optimal number of users. The simulations show that the detection performance of our scheme is improved greatly compared to traditional scheme. In the case of the specific report channels, to achieve the maximum detection probability based on the desired probability of false alarm, the appropriate parameters should be identified, such as the relay amplification gain and the optimum number of cooperative users.