Research On UAV Network User Handover Technology For Emergency Communication

In recent years,unmanned aerial vehicle(UAV)has been widely valued and developed in military and civil fields due to its advantages of diverse functions,flexibility,convenient assembly and low cost.By deploying wireless access equipment on drones,the communication network can be deployed in the air,which can break through terrain restrictions and quickly deploy,and effectively support communication in short-term hotspot areas and emergency scenarios.However,in the multiUAV network,the traditional ground network handover technology is not directly applicable to the UAV communication network,and a new switching technology adapted to the UAV communication network is urgent to study.To this end,this paper first studies the effect of handover execution time on handover performance,and accordingly proposes a multi-UAV deployment method for user mobile handover.Multi-UAV deployment for user mobile handover is modeled as a set covering problem,that is,minimizing the number of UAVs deployed while ensuring user handover performance.Faced with this problem,firstly,the density peak fast search clustering algorithm is used to distill the hotspot area,that is,the hotspot area is divided according to the distribution mode and aggregation degree of ground users and a user distribution model is established.Secondly,based on the new user handover procedure,the indicator of user handover performance in multi-UAV scenarios is derived.Then,for each hotspot area,in order to ensure user handover performance and minimize the number of deployed drones,this paper designs a heuristic algorithm based on the concept of local density to determine the number and location of deployed drones.Finally,the user distribution is modeled based on MATLAB,and the multi-UAV deployment method proposed in this paper is simulated to generate UAV deployment positions covering hotspot areas,and the effect of handover execution time on handover performance is given.The multi-UAV deployment method is feasible and reasonable to ensure the user’s mobile handover performance and corresponding improvement methods are proposed.Subsequently,this paper focuses on the impact of the handover execution process on the quality of communication,and designs a UAV network user handover method based on trajectory prediction.Aiming at the problems of the handover delay caused by the re-association subprocess in the handover execution process,resulting in the decrease of network throughput and transmission delay jitter,this paper first makes full use of the advantages of deploying wireless access points in the air,and obtains the ground environment through the image acquisition system.information,and train a future trajectory prediction model for ground users through a convolutional neural network.Then,according to the future movement trajectory of the ground user obtained by the user trajectory prediction model,the functional relationship expression between the distance and throughput between the ground user and the UAV is deduced,so as to design the UAV network user handover decision condition.Finally,based on the Pytorch platform,the public data set of Stanford University is used to train,evaluate and test the ground user trajectory prediction model,and the user switching method proposed in this paper is simulated based on the MATLAB platform.The results show that,compared with the traditional user handover control method,the user handover control method proposed in this paper can ensure higher network throughput and reduce transmission delay jitter in the case of high handover delay.This paper provides theoretical and simulation support for the research results to further study the new handover technology of UAV network and promote the application of UAV network.