Networking Performance Analysis And Simulation Research Of Unmanned Aerial Vehicle Communication System

Unmanned aerial vehicle(UAV)communication system has the advantages of flexible deployment,balanced capacity and coverage,which can provide efficient and reliable information transmission,comprehensive coverage,intelligent high-quality services and can effectively support the requirements of emergency and hotspot scenarios.Moreover,the development of UAV communication system networking technology still faces the challenges of high dynamic system topology and difficult characterization of system performance,which restricts the application of UAV communication system.Specifically,the performance analysis of UAV communication system at present is mostly aimed at static scenario.The cause law of UAV communication system in user mobile scenario is not clear,especially the lack of theoretical analysis of coverage and handover performance.At the same time,the current research also lacks the system level simulation scheme to describe the impact of user mobility on system performance.Therefore,this paper carries out three parts of research from two aspects:theoretical performance analysis and simulation platform construction.To explore the internal relationship between key parameters(e.g.user speed,UAV base station deployment)and system performance,firstly,a detailed study on coverage performance is presented,and secondly,handover performance of UAV communication system with user mobility is also analyzed.Thirdly,a system level simulation platform of UAV communication system is built in this paper to verify the correctness of the theoretical analysis and explore the actual performance under different system configurations.The main work and innovations of this paper are as follows:1.Coverage performance analysis of UAV communication system with user mobility.Based on stochastic geometry and analytical geometry theory,the system performance metrics such as user handover probability and joint coverage probability in unit time are deduced and analyzed mathematically.At the same time,the correctness of mathematical derivation is verified by Monte Carlo simulation.Theoretical and simulation results show that:(1)The joint coverage performance of 1-tier UAV communication system can be effectively enhanced by reasonably adjusting the UAV deployment density and dynamically adjusting the UAV deployment height according to the user speed.(2)For the 2-tier UAV communication system,the degradation of joint coverage performance caused by user mobility can be compensated by reasonably allocating the proportion of 2-tier UAV base stations.2.Handover performance analysis of UAV communication system with user mobility.Firstly,on the basis of the analytical geometry and stochastic geometry theory,the relationships between user speed and boundary length density and the average number of handover in unit time are quantified.Secondly,based on queuing theory,the UAV base station service model is modeled,and the relationships between access number,system throughput and service time are quantified.Thirdly,the maximum speed constraint of user is analyzed with the analysis above,and the correctness of theoretical analysis is verified by Monte Carlo simulation.Theoretical and simulation results show that reasonably controlling the number and service height of UAVs can significantly improve the transient coverage performance and effectively relax the maximum moving speed constraint of users.3.Construction and performance verification of the system level simulation platform for UAV communication system.Based on ITU and 3GPP protocol standards,the system level simulation platform of UAV communication system is completely designed:including system topology,frame structure,channel model,user mobility and handover,scheduling,adaptive modulation and coding,hybrid automatic retransmission request,antenna and platform architecture.Based on this platform,the coverage performance in chapter 3 and the handover performance in chapter 4 are verified respectively.The simulation results show that the platform can reflect the impact of key parameters of UAV communication system on performance.At the same time,based on the simulation platform,the influences on the actual performance under different settings about antenna design,scheduling strategy,handover configuration and other parameter are further explored.Simulation analysis shows that the joint coverage and transient coverage performance can be improved by configuring omnidirectional antenna,more antenna ports at the transmitter and receiver,Round Robin scheduling strategy,and handover method based on Reference Signal Receiving Power(RSRP).Configuring max C/I algorithm can maximize the throughput and reduce the handover frequency.At the same time,when the user is moving at a high speed,configuring handover method based on RSRP can reduce the handover frequency.The research results of this paper will provide theoretical basis for the actual deployment of UAV communication system,and provide strong simulation support for the setting of UAV communication system performance indicators.