Abstract:

Aiming at the throughput of Unmanned Aerial Vehicle （UAV） relaying system with multiple user pairs， a UAV assisted amplify-and-forward relaying system was investigated， where a Full-Duplex （FD） fixed-wing UAV employed a Time-Division Multiple Access （TDMA） scheduling protocol to provide relay services for multiple source-destination user pairs. With the goal of maximizing the throughput of the system， a joint optimization problem of communication scheduling， the transmit power and trajectory of the UAV was formulated. Since the optimization variables of the problem were coupled， it was non-convex and hence hard to solve directly. To this end， the initial problem was decomposed into three subproblems corresponding to the optimization of communication scheduling， the optimization of transmit power and the optimization of trajectory of the UAV， respectively. On the basis of solving the three subproblems， an iterative algorithm based on the block coordinate descent technique was proposed to tackle the joint optimization problem by optimizing the three variables blocks alternately. Simulation results demonstrate that the throughput of the joint optimization scheme is at least 6.8% and 79.4% higher than that of two benchmark optimization schemes， respectively.

Key words: Unmanned Aerial Vehicle (UAV) relaying, throughput, multiple user pairs, Full-Duplex (FD), Amplify and Forward (AF)

摘要：

针对多用户对无人机（UAV）中继系统的吞吐量问题，研究了UAV辅助放大转发中继系统，其中全双工（FD）固定翼UAV采用时分多址（TDMA）调度协议为多个源-目的用户对提供中继服务。以系统吞吐量最大化为目标，建立通信调度、UAV发射功率和轨迹联合优化问题。该联合优化问题的优化变量之间是耦合的，是很难直接求解的非凸优化问题。因此，将初始优化问题分解为3个子优化问题，分别对应通信调度优化、UAV发射功率优化和轨迹优化。在分别求解3个子优化问题的基础上，提出一种基于块坐标下降的迭代算法，通过交替优化3个变量块来解决联合优化问题。仿真结果表明，与2种基准优化方案相比，联合优化方案的吞吐量分别至少提高了6.8%和79.4%。

关键词: 无人机中继, 吞吐量, 多用户对, 全双工, 放大转发