Research On Access And Routing Technology Of Satellite Internet Of Things Based On SDN

The rapid development of the Internet of Things not only brings many challenges to the current communication system,but also becomes the main application scenario of5G mobile communication system.The satellite communication system has the advantage of not being affected by geographical environment,natural disasters and other factors,it covers a wide area and can provide convenience for the idea that everything is interconnected of the Internet of Things.Therefore,the satellite Internet of Things was proposed.The satellite Internet of Things has the advantages of global coverage and freedom from space restrictions,but it also faces many challenges.First of all,a large number of terminals are connected to satellite network,the access control,handoff and routing strategies caused by motion of satellites or high-speed moving terminals become urgent problems to be solved.At the same time,a variety of devices will inevitably lead to the problem of network heterogeneity.In order to solve the above problems,based on the satellite Internet of Things architecture based on SDN,this thesis proposes an access control framework for satellite Internet of Things based on SDN,studies the access control and handover strategy of multi priority and high dynamic users based on competitive queuing,LEO/GEO dual orbit satellite access control and handover strategy,and proposes the ARIMA model to dynamically predict the number of reserved channels of access control and handover strategy.Finally,the CGR algorithm based on SDN architecture is implemented to deal with periodic and dynamic change.The following is a brief summary of the thesis work.Firstly,based on the traditional satellite access control and handoff technology,aiming at the multi service and high dynamic user problems brought by the access of massive devices in the Internet of Things,the SDN framework is considered to be used for centralized access management and resource allocation.Next,the channel reservation strategy is used to prioritize users according to the priority division.Then,the competitive handover access of each priority is considered to guarantee the performance of high priority users.For the satellite network system,the channel allocation strategy of LEO/GEO satellite communication system with double orbit is considered to deal with the problem of the upper limit of LEO satellite capacity.The simulation results show that the performance of channel allocation strategy of LEO/GEO satellite communication system with double orbit has better service quality.Then,in view of the high dynamics of access users,a method of dynamic channel reservation prediction based on ARIMA model is proposed to predict the handover access generated by access users.Compared with fixed channel allocation and traditional dynamic channel allocation,when the arrival rate of access request exceeds15,the success rate of handoff and the service quality of the system of this strategy are better.Finally,aiming at the dynamic problem of network nodes caused by satellites,a dynamic routing decision system based on CGR algorithm is implemented in SDN architecture.The prediction performance of periodic movement of network nodes is increased,and CGR routing is performed in the form of predicting network topology.Through the test of network performance,it is found that the delay can be controlled within 100ms and the packet loss rate is can be controlled within10^-5,which can satisfy the path finding requirement of dynamic network nodes.