认知无线网络中动态双门限协作频谱感知性能的优化方案

频谱感知作为认知无线电的关键技术，得到广泛深入的研究。其中衡量协作频谱感知性能的主要参数为全局虚警概率和全局漏检概率，它们之和被定义为全局错误概率。本文研究基于双门限能量检测的协作频谱感知性能的优化方案，首先，固定双门限能量检测的检测门限值，对表决融合准则的投票门限进行优化，使得在该能量检测门限值条件下，协作频谱感知的全局错误概率最小；然后在表决融合准则的投票门限取最优值的前提下，对双门限能量检测的检测门限值进行了优化，在不同接收信噪比条件下，最优的检测门限值是动态的，所以要根据信噪比确定最优的检测门限值，使得协作频谱感知的全局错误概率在各信噪比条件下都达到最小值，从而提高了协作频谱感知的性能。仿真结果表明，表决融合准则的投票门限和双门限能量检测的检测门限值取得各自的最优值时，全局错误概率最低，检测性能最好。 

Optimization of Dynamic Double-threshold Cooperative Spectrum Sensing Performance in Cognitive Radio Networks

As a key technology of cognitive radio, spectrum sensing has been extensively researched. The main parameters which measure the performance of cooperative spectrum sensing are the global false alarm probability and the global undetected probability, and the sum of them is defined as global error probability. In this paper, the optimization of cooperative spectrum sensing based on double threshold energy detection is studied. First of all, the voting threshold of the voting fusion rule is optimized under the circumstance of fixed detection thresholds, which makes the global error probability reach the minimum value. Then the detection thresholds of energy detection are optimized under the optimal voting fusion rule. The optimal detection thresholds are dynamic under different SNR conditions, so the optimal detection thresholds are determined by the SNR, under different SNR, the global error probability always reached the minimum value, so the performance of cooperative spectrum sensing gets improved. Simulation results show that the lowest global error probability is achieved when the voting threshold of the voting fusion rule and the detection thresholds of energy detection reach their optimum values respectively.