Research On Optimal Transmission Strategy Of UAV-Enabled Data Collection System

Unmanned aerial vehicles(UAVs)have a great potential for improving the performance of wireless communication.Wide area of coverage and high flexibility also make UAV becomes increasingly popular in communication applications.This paper mainly focuses two sides,one is energy trade-off between ground terminals(GT)and UAV(G2U),the other is UAV trajectory optimization.In addition,the secrecy energy efficiency maximization for UAV-Enabled mobile relay system is discussed in the presence of eavesdropper.The main content of this paper can be summarized in three aspects:(1)Firstly,UAV-enable data collection system in single user scenarios is studied,which leads to a fundamental energy trade-off in G2 U wireless communication.To characterize this trade-off,we consider two practical UAV trajectories,namely circular flight and straight flight.In each case,we first derive the energy consumption expressions of the UAV and GT,and then find the optimal GT transmit power and UAV trajectory that achieve different Pareto optimal trade-off between them.The simulation results verify the feasibility and effectiveness of our scheme.(2)Secondly,multi-user scenarios is studied,where a flexible UAV is deployed to collect data from a group of GT.The GT's uplink transmission energy is a critical factor to measure GT's lifetime.Firstly,this section shows that the energy consumption trade-off between the GT and the UAV in the collection system.Next,using the Lagrange duality and the successive convex optimization,then,we come up with an efficient algorithm aimed to find an approximate solution by jointly optimizing trajectory and resource allocation.In the end,our research scheme is verified by the simulation results.(3)Finally,In the case of eavesdropper in UAV mobile relay system,where a UAV is exploited to collect information from a ground source to legitimate ground destination.We aim to maximize the secrecy energy efficiency of the UAV by jointly optimizing the communication scheduling,power allocation,and UAV trajectoryover a given time horizon.So as to strike a trade-off between the secrecy rate and the energy consumption of the UAV.To track this problem,we propose an efficient iterative problem by applying successive convex approximation and Dinkelbach's algorithm to obtain a high-quality sub-optimal solution.Numerical results validate our proposed joint design method,and also show the significant performance gain,as compared to the benchmarks.Given the above,in UAV-enabled data collection system,trajectory optimization,energy trade-off between G2 U and rational allocation of wireless resources can effectively improve the performance of communication system.This paper shed new light on designing energy-efficient UAV communication in future wireless system.