基于协作频谱感知的多无人机通信网络谱效优化研究

针对无人机应用场景频谱效率较低的问题，提出一种结合认知无线电技术的多无人机通信网络谱效优化方案.首先基于协作频谱感知，建立空地信道下多机协作的认知无人机网络模型，设置无人机（unmanned air vehicle，UAV）数量、感知时间和判决门限等优化参数，在此基础上提出高谱效联合优化算法对构建的非凸优化问题求解，最后分析无人机飞行过程中谱效的变化情况.仿真结果表明，存在最优感知时间使系统谱效获得最大值，且UAV数量和判决门限等因素会影响该谱效最优值；提出的高谱效联合优化算法具有较好的收敛性，有效提高了UAV次级认知网络的频谱效率. 

Spectrum Efficiency Optimization of Multi-UAV Communication Network Based on Cooperative Spectrum Sensing

Aiming at the low spectrum efficiency (SE) in application scenarios of unmanned air vehicles (UAV), an average SE optimization scheme of multi-UAV communication network combined with cognitive radio (CR) was proposed. Firstly,based on cooperative spectrum sensing (CSS), a cognitive UAV network model was established for multi-UAV cooperation in air to ground (A2G) channel, setting the optimization parameters such as number of UAVs, sensing time and cooperative decision threshold. Then,the average SE optimization problem of UAV was investigated, and a joint optimization algorithm was proposed to solve the non-convex optimization problem. Finally, the change of SE in the flight course of UAV was analyzed. The simulation results show that there is an optimal sensing time to maximize the SE, and the number of UAVs and decision threshold will affect the optimal value of SE. In addition, the proposed algorithm has better convergence and can effectively improve the average SE of UAVs in the secondary network.