Research On Joint Resources Allocation And Trajectory Optimization For UAV-Assisted Communication Networks

The rapid advent of mobile Internet,Internet of things,and related science and technology has sparked the emergence of various new applications,entailing substantial conveniences to people and enormous challenges to communication networks.The ways to meet the increasing demand for communication is an urgent issue requiring addressing.However,the conventional solution of densely deploying communication base stations on the ground entails high deployment costs.It exacerbates the interference between cellular cells,which hardly meets the communication needs of ground users.UAV-assisted communication possess the singular advantages of easy deployment,high flexibility,and low cost,which is deemed an effective method to solve the deficiency of existing communication networks.However,both the UAV movement trajectory and resource(bandwidth,computation,power)allocation significantly impact the service quality of the communication networks.On the one hand,the energy consumption caused by UAV flight and service significantly shortens the service time of UAV-assisted communication networks;On the other hand,UAV communication resources are limited,and in the case of a determined UAV trajectory,resource allocation will directly impact the quality of service for ground users.Therefore,UAV trajectory design and resource allocation in UAV-assisted communication networks have garnered significant attention in academic spheres.Despite numerous studies on resource allocation and trajectory design of UAV-assisted communication networks,energy efficiency and quality-of-service of users have not been fully considered.After reviewing the existing methods and previous work,this thesis delves into the issue of resource allocation and UAV 3D trajectory optimization for four types of UAV-assisted communication networks.The main innovations and contributions of this paper are as follows:1.This thesis proposed a method of joint resource allocation and UAV 3D trajectory optimization in single UAV-assisted communication networks.For single UAV-assisted communication networks,considering the limited communication bandwidth resources,the limited UAV energy,and the difference in wireless multimedia service requests of ground users,the rational allocation of bandwidth resources and the design of the UAV 3D trajectory is essential in improving the energy efficiency of the communication network and guarantee the quality-of-service requirements for all users.To this end,this thesis constructs a joint optimization problem of UAV 3D trajectory design,user communication scheduling,bandwidth resource allocation,and UAV transmitting power allocation aiming at energy efficiency.Given that the proposed optimization problem is a multi-parameter fractional nonconvex problem,existing optimization algorithms cannot solve the optimization problem independently.Therefore,this thesis solves the optimization problem through the Dinkelbach and Block-Coordinate-Descent(BCD)algorithms.The optimal UAV 3D trajectory and resource allocation can be yielded.The simulation results demonstrate that the proposed optimization scheme can guarantee the service requirements of users,and the energy efficiency is at least12.5% higher than the existing optimization scheme.2.This thesis proposed a method of joint resource allocation and UAV 3D trajectory optimization in MEC coordinated single UAV-assisted communication networks.Aiming at the coexistence of wireless multimedia services and high-intensive computing services,and the diversified demands of wireless multimedia services,this thesis further delves into the problem of joint resource allocation and UAV 3D trajectory optimization for MEC coordinated single UAV-assisted communication networks.Given the bandwidth competition between communication users and computing users,the self-interference of full-duplex UAV,and the aggravated energy consumption of the UAV due to the load of a base station and computing equipment simultaneously,which significantly shrinks the service time of the communication networks.This thesis designs a model of joint resource allocation and UAV 3D trajectory optimization aiming at computational efficiency.For the fractional objective function and nonconvex constraints in the optimization model,the fractional programming theory was used to deal with the fractional objective function.This thesis uses the Successive-ConvexApproximation(SCA)method to transform the nonconvex function and constraints into convex.The simulation results show that the scheme proposed in this thesis possesses increased computational efficiency and can guarantee service requirements for all users compared with the existing research work.3.This thesis proposed a method of joint resource allocation and UAV 3D trajectories optimization in MEC coordinated multi-UAV-assisted communication networks.Given the strict size and weight restrictions of the UAV,the battery capacity of the UAV is limited,resulting in the inability of a single UAV communication network to guarantee both the service time and quality of service.Thus,this thesis studies the optimization of resource allocation and UAV 3D trajectory in MEC coordinated multi-UAV-assisted communication networks.However,the deployment of the multi-UAV-assisted communication networks faces issues such as bandwidth resource competition among UAVs,bandwidth resource competition within a UAV,collision,and communication interference.Under such a background,this thesis constructs a model of joint optimization UAV 3D trajectory design,time allocation,bandwidth resource allocation,and UAV transmission power control aiming at energy efficiency.Since the objective function of the optimization model is a fractional multivariate function,the suboptimization problems of UAV 3D trajectory and UAV transmission power control are nonconvex optimizations.Therefore,after using the SCA algorithm to transform the nonconvex constraints into convex,a multi-stage alternate iterative optimization method is used to address these issues.The simulation results prove that the proposed optimization scheme can achieve higher energy efficiency compared with previous research work.4.This thesis proposed a method of joint resource allocation and UAV 3D trajectories optimization in multi-UAV and satellite-assisted communication networks.Due to the limited coverage and service time of a single UAV communication base station,the UAV communication networks cannot guarantee coverage,service time,and cost simultaneously.With the rapid development of satellite communication technology and applications,the combination of communication satellites and UAV communication networks is feasible.Therefore,this thesis further studies resource allocation and 3D trajectory optimization in UAV and satellite cooperative assisted communication networks.Regarding the disparity in the quality between the air-to-ground and the air-to-air channels,the difference in the energy consumption between communication and computing,the interference of UAV communication,and the significant impact of UAV energy consumption on the lifetime of the networks,this thesis constructs the problem of joint optimization UAV 3D trajectory design,bandwidth resource allocation,and UAV transmit power control.This thesis uses the first-order Taylor relaxation process to transform the suboptimization problems of UAV 3D trajectory and UAV transmission power control into convex,and the variable replacement method is subsequently used to solve them iteratively step by step for a multi-parameter nonconvex optimization problem.The simulation results show that the proposed optimization scheme can yield higher energy efficiency compared with the existing research work.