Research On Access Mechahism Based On Bearer For Satellite Network

As a supplement to the ground communication network,the LEO(Low Earth Orbit)Satellite Network provides seamless coverage of communication services for the ground by building constellation systems through a large number of satellite nodes,and truly realizes the "ubiquitous connection" of the global network,which is an important direction of future communication development.With the continuous expansion of the Satellite Network,the number of satellite nodes becomes more and more intensive,and the number of visible satellites on the ground terminal also increases.The traditional satellite access strategy will bring frequent satellite ground access handovers,which will have a great impact on the continuity of business.In this context,it is necessary to explore new access mechanisms to deal with the frequent access and handover operations of LEO Satellite Network.At the same time,Satellite Network communication has developed from a simple "satellite access" to a fusion mode of "satellite access and inter satellite transmission".In terms of service quality of service(QoS)requirements,the end-to-end performance of LEO Satellite Network is the whole coupling of access and bearer.If the performance of access and bearer cannot be coordinated,the superposition of a large number of access requests will make the bearer side an important bottleneck in business access performance.Therefore,this thesis carries out the research on the access mechanism of bearing perceptible Satellite Network,considers the difference of bearing performance brought by different satellites,and proposes an optimization scheme from two perspectives:the selection of access satellites and the allocation of access resources,to improve the access process.Firstly,in the multi satellite overlapping coverage scenario of LEO Satellite Network,this thesis designs a terminal access management mechanism with joint access and bearer,and proposes an access selection strategy with satellite route awareness.In response to the traditional access strategy that only considers the impact of satellite access channel quality,this article constructs an end-to-end service capability evaluation model for satellites based on access and carrier performance.By combining satellite elevation,remaining service time,number of idle channels,and inter satellite path quality,terminal independent access decisions are achieved to ensure the service quality requirements of the business.After simulation verification,compared to traditional satellite access strategies,the strategy proposed in this article effectively achieves end-to-end performance guarantee while achieving lower call blocking rates.Secondly,aiming at the access resource allocation problem faced by differentiated service requirements in LEO Satellite Network,this thesis proposes a multi task resource allocation algorithm based on end-to-end QoS decomposition at the access and carrier sides.Relax the service time constraints on the access side based on the end-to-end performance requirements of the business,combined with the load of the access network and the performance of the carrier network.In the case of insufficient satellite node capacity,bandwidth resources should be reasonably downgraded considering the priority of services.At the same time,the time-frequency resource allocation problem on the satellite access side is abstracted as a two-dimensional packing problem,and the packing process is executed sequentially using a BL like(Bottom Left)algorithm.Genetic algorithm is used to optimize the scheduling order of services,thus achieving the resource allocation scheme with the highest overall priority.The simulation results verify that the resource allocation scheme with time relaxation and service degradation achieves good performance in terms of scheduling benefits,resource utilization,and access success rate.