Research On Deployment Optimization Of Unmanned Aerial Vehicle Assisted Ground Wireless Communications

With the rapid development of various smart devices,the number of terminal devices and amount of mobile data in next-generation wireless communication systems will explode.At the same time,the access of smart terminals will also generate various kinds of services,which have different communication performance requirements.The explosive growth of mobile terminals,mobile data and various service requirements have brought new challenges to existing cellular networks,especially in some areas where the communication infrastructure is insufficient.In such kinds of areas,the communication problems become more serious when communication infrastructures are damaged and communication service needs increases sharply.In recent years,drones have begun to be applied into various fields,including security,patrol,data acquisition,and communication.Meanwhile,using UAVs(Unmanned Aerial Vehicles)to assist existing wireless communication systems has become a research hot topic,due to the advantages of high mobility,easy deployment and good communication links of UAV air base stations.Considering that the channel characteristics of UAV air-to-ground wireless communication systems are significantly different from traditional ground cellular communication systems,the channel model of UAV air-to-ground wireless communication systems is derived and analyzed in this paper.Then,a UAV-assisted Io T(Internet of Things)data backhaul communication system is proposed to solve the problem of limited data backhaul in traditional Io T systems.The proposed communication system can help data backhaul and maximize the energy efficiency of the system.The energy efficiency optimization problem of this system involves joint optimization of multiple variable parameters,and is a non-convex problem.So a joint optimization algorithm based on successive convex approximation technology is proposed to solve the energy efficiency optimization problem.The simulation results show that the proposed algorithm can effectively improve the energy efficiency of the proposed system.Finally,the combination of multiple UAVs and terrestrial base stations are considered to jointly serve ground users,as traditional terrestrial cellular networks can’t meet communication requirements of cell-edge users.The proposed method improves edge users’ service rate by optimizing the deployment of multiple UAVs.The UAVs deployment optimization problem is a mixed integer non-convex problem,and is divided into two sub-problems of determining the number of UAVs and optimizing the location of UAVs.The Louvain algorithm and heuristic algorithm based on feasibility constraints are used to solve these two sub-problems.Simulation results show that the proposed scheme can effectively improve users’ service rate.In this paper,two specific application scenarios of UAVs in wireless communication systems are modeled and analyzed.Corresponding algorithms are proposed to optimize the energy efficiency and the rate of communication systems,respectively.Simulation results show that the proposed algorithms in this paper can effectively improve the energy efficiency and the rate of corresponding communication systems.The research investigated in this paper may provide some new solutions for the future UAVs’ applications in wireless communications.