Research On Performance Analysis And Optimization Technology Of Space-Terrestrial Integrated Network

Traditional ground-based networks are limited by communication infrastructure,transmission line and maintenance means,and cannot be deployed to places with complex environments.In order to meet the requirements of highly reliable communication,it has become a future development trend to establish a space-terrestrial integrated network composed of satellite network,near space networks and ground networks.However,it is difficult to achieve efficient interconnection between the closed and isolated networks.Moreover,with the addition of mobile nodes,the complexity of the network and the cost of network management are further increased,which makes it more difficult for the network to meet the requirements of communication services with low delay and high reliability.In order to solve the above problems,heterogeneous network integration,network optimization management are put forward to achieve high mobility support and efficient interconnection.The thesis focuses on the space-terrestrial integrated network architecture,performance analysis,and handover prediction optimization.It mainly includes three aspects as fellow:Firstly,a space-terrestrial integrated network architecture is proposed.SDN,NFV and MEC technologies are introduced into the space-terrestrial integrated network system.At the date level,according to the characteristics of regional distribution,the network nodes are added to achieve full coverage,and the MEC server is used to complete the efficient calculation and processing of data.At the control level,considering the status of individual network elements,and the occupancy of communication links,the controller makes relevant decisions to achieve efficient and reliable network resource management,effectively guide data transmission.Second,thesis analyzes the reliability of the spectrum-sharing satellite-terrestrial integrated network.The base station is modeled as a two-dimensional Poisson point process,and the low-orbit satellite is modeled as a three-dimensional Poisson point process.Considering the inter-component interference and intra-component interference between the base station and the satellite,the average outage probability and the success transmission probability of continuous service data are derived by using stochastic geometric model.Finally,the theoretical results are verified by simulation results,and the effects of satellite density,base station density and other parameters on the reliability of the considered network are shown.Third,thesis proposes a network handover path based on the time evolution graph and the best handover time prediction strategy.By modeling the motion state of the terminal,a time evolution map of the coverage time of each node to the terminal is obtained based on the satellite motion law and the distribution characteristics of the base station.The minimum path method is used to predict the network handover path,and then the optimal handover point is predicted by calculating the maximum cumulative signal quality.The simulation results show that this strategy can be well adapted to various types of terminals and meets the needs of different types of communication services.