Research On Wireless Transmission And Resource Allocation Method Based On UAV-Assisted Maritime Communication

With the continuous development of wireless communication technology,the 6th generation mobile communication system is committed to building a fully connected communication world,and the research of UAV application in wireless communication network is becoming more and more common.Compared with the traditional ground communication infrastructure,the use of UAV assisted maritime communication network has great advantages,such as UAV can provide line-ofsight link to improve the quality and capacity of communication,UAV’s high mobility and flexibility make it can adapt to the complex maritime communication environment,and UAV communication coverage is wider and the cost is lower.When using UAV to assist maritime communication,different from the existing UAV air-to-ground communication research,a new maritime communication channel model needs to be established,and there are high requirements for UAV energy consumption and resource allocation.In view of the above problems,this thesis carries out the research on the theory and technology of wireless transmission and resource allocation based on UAV assisted maritime communication.The specific research contents are as follows:Firstly,the main characteristics of maritime communication environment and the impact of maritime environment on wireless communication are introduced in detail,and the two-ray channel model and three-ray channel model of maritime communication are compared.Then it introduces the principle,implementation steps,advantages and disadvantages of K-means clustering algorithm.Finally,the theoretical basis of convex optimization and CVX toolbox are introduced.Secondly,aiming at the resource allocation problem of UAV assisted maritime communication,a joint optimization method of transmit power and trajectory is proposed,which aims to maximize the minimum average rate of users and ensure the communication quality of all users.In order to solve the proposed non-convex optimization problem,the original problem is decomposed into two subproblems by introducing auxiliary variables and separating coupling variables,and then the two subproblems are iteratively optimized alternately to obtain an approximate suboptimal solution of the original non-convex problem.The simulation results show that the proposed method of joint optimization of UAV transmit power and trajectory can significantly improve the average user rate.Finally,aiming at the scene of multi-UAV assisted maritime communication,a transmit power and trajectory optimization method is proposed under multi-UAV assisted mobile user communication.According to the location information of maritime users,K-means clustering method is used to cluster users.Then,in order to maximize the user throughput,the optimal communication position and transmit power of UAV in each cluster are calculated.Finally,the optimal communication position of UAV in adjacent time slots is matched to obtain the optimal flight path of UAV.In order to solve the non-convex optimization problem proposed in this chapter,based on the idea of greedy algorithm,the original problem is decomposed into three sub-problems to solve,respectively,user clustering problem,resource allocation problem and trajectory optimization problem.The successive convex approximation algorithm is used to iteratively optimize the subproblems,and an approximate suboptimal solution of the original nonconvex problem is obtained.Simulation results show that the proposed transmit power allocation and trajectory optimization method for multi-UAV assisted mobile user communication can significantly improve the user data throughput.