DF-UAV中继广播通信系统航迹优化方法

Trajectory optimization method of the DF-UAV relay broadcast communication system

无人机中继通信系统可以为用户提供高质量服务和多种业务辅助,而无人机航迹优化是无人机中继通信系统面临的关键技术问题之一。针对译码转发协议下的无人机中继广播通信系统,研究其航迹优化方法以提高系统链路传输性能。首先,建立了无人机中继通信系统模型,分析给出单用户链路中断概率和系统平均中断概率计算公式,在此基础上提出基于最大用户中断概率最小化准则的中继无人机航迹优化方法,并理论推导出系统的遍历容量精确数学表达式;接着通过计算机仿真分析验证了服务区域半径、最大转弯角、路径损耗因子、发射功率等系统特征参数对中继无人机最优航迹、系统中断性能和系统容量性能的影响,同时对比了相同的优化准则下两种中继转发协议的系统中断性能和容量性能。仿真实验表明,与放大转发协议相比,译码转发协议下的中断性能和容量性能均有明显提升,从而验证了所提航迹优化准则的有效性。

An unmanned Aerial Vehicle(UAV)relay broadcast communication system can provide a high quality service and multiple business assistances for users.UAV trajectory optimization is one of the critical technical problems of the UAV relay communication system.The trajectory optimization methods are investigated to improve the link transmission performance of the UAV relay broadcast communication system with the decode-and-forward protocol.First,the UAV relay broadcast communication system model is established.The calculation formula for the interruption probability of a user link and that for the average interruption probability of the communication system are given.After that,a trajectory optimization method based on the criterion of minimizing the maximum outage probability for all users is proposed,and the mathematical expression for the accurate ergodic capacity of the UAV relay broadcast communication system is theoretically derived.Finally,the influence of system characteristic parameters such as service area radius,maximum turning angle,path loss factor and transmitting power on the optimal track,system interruption performance and system capacity performance of the relay UAV is verified by computer simulation.Meanwhile,the system interruption performance and system capacity performance of two relay forwarding protocols are compared under the same optimization criteria.Simulation results show that the outage performance and capacity performance of the decode-and-forward protocol are significantly improved compared with the amplify-and-forward protocol,which verifies the effectiveness of the proposed trajectory optimization criterion.