Trajectory Design Oriented Throughput Optimization In Uav Wireless Powered Communication Networks

Nowadays,UAVs(Unmanned Aerial Vehicle,UAV)has become a hot topic of discussion.Its rapid development and continuous technological advancement make it applied to various fields in life.At the same time,the research system of WPCN(Wireless Powered Communication Networks,WPCN)is also constantly To progress.For the traditional WPCN system,due to its fixed access point,the end-to-end information transmission efficiency is low,and there is usually a "doubly near-far" problem that leads to serious fairness issues among users.At the same time,the problem of low-power node energy supply in the network is also a major challenge,so the traditional WPCN fixedpoint access technology is no longer suitable for multi-user distribution scenarios.However,according to the UAV’s high mobility characteristics,its trajectory can be flexibly designed to be used in the WPCN system.This thesis is just considering the combination of UAV and the system and apply it to this scenario.UAV as The air node supplies energy to the ground users,and at the same time combines the trajectory and resource allocation of the UAV to solve the fairness problem between the ground users.The main work of this thesis is as follows:First of all,this thesis considers the application of drones to the WPCN system.The drones are used as mobile access points in the air for scheduling and serve a group of users on the ground according to a certain communication period.The user charges,and the user uses the energy collected by the radio frequency to send independent information to the drone through the uplink.The maximum speed constraint of the drone and the user’s energy constraint are considered in the problem.The goal is to use the movement of the drone.Its trajectory is designed to maximize the minimum throughput of ground users,thereby solving the issue of fairness among users.As a result of the non-convex characteristic of the problem,this thesis ignores the maximum speed constraint of the UAV to relax it,and gives the solution to the relaxation problem to obtain a multi-position hovering solution.Finally,based on the solution of the relaxation problem,the original text is given.The solution algorithm obtained the continuous hovering flight trajectory design of the UAV.Secondly,for the original problem,this thesis applies alternate optimization and gives its solution based on the continuous convex approximation method.At the same time,it assumes two contrasting solutions,namely the fixed-point hovering transmission scheme and the limiting user transmission power scheme.These schemes are solved and combined with We compare the algorithms proposed in this thesis to prove that the algorithm proposed in this thesis can indeed improve the performance of the system.At the same time,it analyzes the complexity of the algorithm proposed in this thesis and the algorithm based on SCA(Successive Convex Approximation)to verify the superiority of the algorithm.Finally,this thesis takes into account the practical application of the algorithm,uses the existing UAV platform in the laboratory,and based on the ROS(Robot Operating System)system to carry out the secondary development of the DJI UAV,and through hardware design and software development,the algorithm proposed in this thesis is transplanted and packaged into the UAV platform,and the terminal simulation flight test and outdoor actual flight demonstration are performed.Finally,the function of the algorithm is verified and the practical application value of the algorithm in this thesis is reflected.