Research On Energy-Efficient UAV-Assisted Communication And Topology Management For Flying Ad Hoc Networks

UAV communication is an important part of future communication wireless technology.Compared with fixed communication devices,UAV has outstanding features such as flexible deployment,strong line-of-sight connection links,and adaptive height,which make them have many key potential applications in wireless systems.The application scenarios of UAVs are mainly accidents or emergencies,such as disaster relief and service recovery scenarios.In this case,deploying terrestrial infrastructure is not economically viable due to high operating costs,complex and variable environments.The use of UAV for auxiliary communication,or as an air base station,can better improve network performance and flexibly improve network coverage.At present,UAV have a large application market and development potential,and also put forward new requirements for the quality of UAV communication links.There are still a lot of treasures to be developed for UAV communication.Whether in academia or industry,it has aroused widespread concern.In the upcoming 5G era,UAV communication has broad application prospects.This paper considers a cellular system that utilizes a unmanned UAVs to provide communication channel for the cell-edge users offloaded by the MBS,and establishes the optimization problem with energy efficiency as the main objective function.In addition,the problem of topology establishment,adjustment and delay analysis in the flight ad hoc network(FANET)was studied.The main work is as follows:1.A cellular system that utilizes a UAV as an airborne mobile base station and circulates along the edge of the cell to serve the edge users offloaded by the macro base station is studied.Compared with the femtocell access point,the UAV has the unique advantages of high mobility,flexible deployment and control,large coverage of aerial work and convenient updating of communication equipment.It can provide better communication for edge ground terminals.On the basis of this theoretical model,by jointly optimizing the spectrum allocation of UAV and macro base station(GBS),UAV flight speed and user division,a reasonable optimization algorithm is proposed to maximize the energy efficiency of the UAV.The simulation results show that the proposed scheme achieves better energy efficiency by adopting the optimal UAV flight strategy and spectrum allocation strategy.2.The topology management and performance analysis problems in a flight adhoc network composed of multiple UAV and one GBS are studied.In a flying ad hoc network,multiple UAVs can perform complex tasks compared to a single UAV.The FANET is also more stable and powerful when a UAV disconnects from the users.However,due to the flexible mobility of the UAV,the topology changes rapidly.In this paper,considering the establishment of the topology in the flight ad hoc network,the shortest path first algorithm(SPFA)is used for adjustment.Two schemes for updating the routing path are introduced,and then the reliability analysis is performed based on the time delay.It can be seen from the simulation results that compared with the random UAV relay selection scheme,the topology management scheme proposed in this paper achieves better performance.