基于无人机辅助的认知无线电网络信息年龄研究

考虑到信息时效性和数据新鲜度对各类实时状态更新系统带来的挑战，提出了一种无人机（Unmanned Aerial Vehicle， UAV）中继辅助的认知无线电网络（Cognitive Radio Network， CRN）信息年龄（Age of Information， AoI）最小化方案。为了降低CRN中次用户接收机处的AoI，在不影响主用户正常通信的前提下，利用UAV作为移动中继来辅助次用户发射机将数据包传输到对应的接收机。通过联合优化UAV的飞行轨迹和资源分配来确保信息新鲜度。由于联合设计问题是非凸的，故采用连续凸逼近的高效迭代算法得出问题的最优解。仿真结果表明，所提方案可以有效提高信息新鲜度，并获得峰值AoI的最小值。同时，数据包的大小和数量与AoI呈线性关系，对UAV的飞行轨迹也有影响。 

Research on Age of Information in UAV-assisted Cognitive Radio Networks

Considering the challenges of information timeliness and data freshness to various real-time status update systems， an unmanned aerial vehicle （UAV） relay-assisted cognitive radio network （CRN） age of information （AoI） minimization scheme is proposed. To reduce the AoI at the secondary user receiver in CRN， UAV is used as mobile relay to assist the secondary user transmitter to transmit data packets to the corresponding receiver without affecting the normal communication of the primary user. The flight trajectory and resource allocation of UAV are jointly optimized to ensure the freshness of information. Since the joint design problem is nonconvex， an efficient iterative algorithm of successive convex approximation is used to obtain the optimal solution of the problem. Simulation results show that the proposed scheme can effectively improve the information freshness and obtain the minimum value of peak AoI. Meanwhile， the size and number of packets are linearly related to AoI and have an impact on the flight trajectory of UAV.