Research On MAC Layer Mechanism Of Integrated Navigation And Communication Satellite Network

With 5g technology is put forward,the ground communication network is in rapid development phase.But due to the limitations of ground communication network in coverage,construction cost and maintenance cost,some remote areas cannot fully cover mobile base stations.Satellite communication with the advantages of wide coverage and easy to achieve global coverage,which makes up for the shortage of ground communication system,well made up for the inadequacy of ground communication systems.Therefore,satellite mobile communication technology has become an important research direction in the current communication field.The traditional satellite navigation system can only achieve positioning,timing,navigation and other functions.The short message service is a new service proposed to expand the business field of satellite navigation system,which has become a research hotspot in the current industry.The integrated navigation satellite communication network uses the same satellite or the same satellite constellation to carry the navigation and communication functions.On the basis of realizing the navigation function,it uses the remaining resources to increase the short message communication function between the user terminals of the satellite.This thesis researches and analyzes the conduction integration on the basis of the characteristics of satellite communication network and the network architecture,network schemes of satellite communication network and data communication access to study the mechanism and process.It designs a multiple access at the MAC layer protocol mechanism,which can use the limited communication satellite system resources to provide mobile users with short message communication service,specifically including the design of the protocol data transmission mechanism,user access mode,network access priority control mechanism and sharding mechanism.Then the communication network simulation software is designed to simulate and verify the communication mechanism and business process of the terminal.The applicability and performance of the communication mechanism and business process are analyzed and evaluated.This thesis's innovation lies in:Firstly,it proposes a downward circular frame rapid feedback mechanism,indirectly to listen for channel busy or hidle state and detect conflict.In the integrated navigation and communication satellite network which has a large user number and little communication resources,the users cannot listen to channel scenario.The method can reduce the blindness in uplink data frame transmission process and improve the utilization rate of channel.Secondly,a multi-channel packet notification method is proposed,which can reduce the waiting time before sending the uplink data frame in the multi-channel scenario and ensure the packet access as soon as possible.Thirdly,on the basis of the above mechanisms,a priority mechanism,a sharding mechanism and a downlink data frame transmission mechanism are added to the protocol to meet the business requirements in this scene.Firstly,this thesis analyzes and systematically studies the characteristics and network architecture of the integrated satellite communication network.It fully understands the characteristics,networking scheme and data communication access mechanism of the integrated satellite communication network.It makes clear the significance of the designed MAC layer protocol mechanism and the requirements which need to be met.The parameters of the integrated satellite communication network,including the network topology,channel resource conditions and the number of nodes,are studied in depth.Then,according to the characteristics of integrated satellite communication network,a MAC layer multiple access protocol mechanism is designed.Finally,the simulation software of the protocol mechanism is designed and implemented on OPNET simulation platform.The correctness and effectiveness of the designed protocol mechanism are verified in different scenarios.The results show that the MAC layer protocol mechanism designed in this thesis has better performance and higher flexibility than the classical MAC layer protocol mechanism.It can be seen that the MAC layer protocol mechanism designed in this thesis can better adapt to the scenarios of conducting integrated satellite communication network,and it is of great significance to the research of conducting integrated satellite communication system MAC layer.