| With the continuous development of satellite communication technology,satellite communication has penetrated into all aspects of our lives,from a single voice service to multimedia and broadband data services.However,the channel capacity of satellites is limited.How to improve the channel utilization rate under the limited channel capacity is a huge challenge,at the same time,the existing satellite multiple access protocol has the problem of incomplete consideration of practical factors.In addition,due to the particularity,flexibility,and difficulty of large-scale ground physical testing of satellite communication systems,the realization,evaluation,and verification of satellite communication networks are very difficult,Therefore,it is urgent to develop a comprehensive simulation demonstration verification system for satellite communication networks.In this paper,the following two parts are studied under the high orbit satellite communication scenario.In the research on the allocation of high-orbit satellite communication resources,it is found that the existing satellite multiple access methods have the problems of incomplete consideration of practical factors and low channel utilization.Therefore,on the basis of the existing Combined Free/Demand Assignment Multiple Access CFDAMA,a Combined Free/ Demand Assignment Multiple Access-Variable Constraint CFDAMA-VC is proposed.Firstly,CFDAMA-VC adds two variables,user priority and maximum tolerable delay,on the user side,and builds a user "value" formula on the basis of the two variables,making the satellite multiple access protocol consider practical factors more comprehensive.Secondly,on the satellite side,the channel resource allocation is modeled as a 0/1 knapsack problem,and the optimal user set is obtained through dynamic programming to complete the optimal scheduling of channel resources to solve the problem of low channel utilization.Finally,the simulation of the CFDAMA-VC protocol is completed in the communication network simulation software OPNET.The results show that: compared with the CFDAMA protocol,the CFDAMA-VC protocol can reduce the average packet loss rate of the system by about5%,and the high “value” users of the CFDAMA-VC system have lower user packet loss rates and user end-to-end delays compared to low “value” users.In the research of the existing satellite communication network simulation software,it is found that the function of a single simulation software can only be limited to a certain field,and the current satellite communication network presents complexity and diversity,traditional verification methods through printing and pure data analysis cannot achieve the purpose of effective experiments,therefore,a comprehensive simulation demonstration system that can combine multiple simulation software and reflect the simulation experiment process and results more intuitively is developed.The various sub-systems of the integrated simulation system complete the interaction of simulation data through the Ethernet.Due to limited time,the comprehensive simulation system only completes the development of the satellite communication network simulation sub-system and the comprehensive display subsystem,and the completed sub-system can already realize most of the functions of the entire simulation system.The satellite communication network simulation sub-system is composed of the communication network simulation software OPNET,the aerospace field simulation software STK,and the C++ program of its own protocol simulation;the comprehensive display sub-system is mainly supported by the C# program.The comprehensive simulation system completes the simulation of the satellite communication network by the satellite communication network simulation sub-system,and transfers the data in the simulation process to the comprehensive display sub-system for visualization processing.Finally,the simulation process and results can be displayed dynamically,and can verify the correctness of its own satellite communication protocol. |
PDF Full Text Request