Research And Simulation Of Switching Mechanism In Satellite-ground Hybrid Network

The satellite-ground fusion network is a network application scenario that combines the advantages of wide-area coverage of satellite networks and high-speed links of terrestrial networks.Because satellite networks use line-of-sight transmission,the presence of high-rise buildings in urban areas will lead to a reduction in the quality of satellite communications.In recent years,Ancillary Terrestrial Component(ATC)has been widely used in satellite-ground fusion networks.The quality is reduced and the spectrum resources of the satellite network are used to a greater extent.The satellite-ground fusion network using ATC can effectively combine the advantages of terrestrial and satellite networks and complement each other.In the satellite-to-ground fusion network,in order to ensure continuity of calls and automatic network adaptation,users need to have the ability to smoothly switch and intelligently choose to access the network.So handover mechanism is an important research content in satellite-ground fusion network.Aiming at the handover problem in LEO-ATC heterogeneous fusion network,a user-based satisfaction handover algorithm is proposed,and is verificated in simulation in this thesis,the main content of this article is as follows:First,in this thesis,the LEO-ATC heterogeneous fusion network architecture is introduced where low earth orbit(LEO)satellite networks and ground-assisted base stations are fused,and a network simulation model is built.Based on the characteristics of LEO-ATC heterogeneous fusion networks,an optimization direction is proposed for the traditional handover process and multi-attribute decision-making algorithm in this thesis;Second,a satellite-to-ground fusion network simulation platform is designed and implemented based on OPNET software in this thesis.The platform is composed of ATC network and satellite network,which implements different types of nodes,such as user,satellite,base station and core network,etc.,and can complete functions such as network routing and network switching between ATC network and satellite network and satellite beams.Third,the traditional multi-factor decision switching algorithm has similar switching results to the user group when the candidate network decision attribute values are similar,and leads to a local traffic surge and affecting system performance.To address this issue,this thesis starts from the perspective of global resource optimization(meeting as much as possible to meet the QoS requirements of each user,reducing network congestion as much as possible,and using spectrum resources as much as possible).The service index achievement degree is mainly represented by the demand guarantee situation of the user terminal’s call quality and multi-service requests in different environments),and a method to obtain the user service indicator achievement degree of each network by combining user requests and network service conditions A handover decision algorithm for handover target network is obtained.In the LEO-ATC heterogeneous fusion network,the algorithm can balance global traffic well and avoid local congestion.After that,the performance of the proposed algorithm is compared with the traditional SAW,TOPSIS and AHP from four aspects:switching disconnection rate,network load,packet arrival blocking rate and network switching frequency.Simulation results prove that the algorithm proposed in this paper has greatly improved the switching performance of the LEO-ATC heterogeneous converged network,and can well relieve the local traffic surge and improve system performance...