Research On QoS-aware Multicast Routing Of Low Earth Orbit Satellites

In recent years,with the rapid growth of data traffic,low earth orbit(LEO)satellite network has attracted more and more attention and research due to its global seamless coverage,high communication quality,low communication delay and low launch difficulty.At the same time,with the development of the Internet and the rapid growth of the number of user terminals,applications involving multiple participants,such as video distribution,multiplayer games,etc.,account for an increasing proportion of traffic.As an efficient communication method,multicast routing is becoming more and more important in LEO satellite network communication.However,due to the high dynamic of satellite network topology and the different requirements for quality of service(QoS)of applications,the traditional distributed IP multicast is difficult to apply,which brings challenges to LEO satellite QoS-aware multicast routing.Therefore,this thesis studies the QoS-aware multicast routing of LEO satellite network.The main work contents are as follows:1.In this thesis,the weighted LEO satellite network model is proposed.In order to meet the different requirements for multicast communication QoS of different applications,the weighted inter satellite link is considered in the calculation of multicast routing,the centralized construction of the multicast tree is carried out in the weighted network.While realizing the QoS-aware multicast routing,the multicast efficiency has been greatly improved.2.In this thesis,a Weighted Rectangular Steiner Minimum Tree(WRSMT)construction algorithm based on edge substitution is proposed to realize the QoS-aware multicast routing of LEO satellite.WRSMT uses the concept of Voronoi diagram,divides the nodes in the network according to the distance from the group members,realizes the global search of candidate Steiner points according to the dual graph Delaunaytriangulation,takes the minimum spanning tree as the initial solution,and then introduces Steiner points into the initial solution through edge substitution to complete the construction of multicast tree.3.This thesis proposes a multicast tree management strategy based on edge substitution to support dynamic group member change and fault recovery in multicast routing.The core strategy of tree management is the local reconstruction of multicast tree.For the changed members or fault parts,the Voronoi diagram is updated locally,and then the Steiner point is searched locally.Finally,the best Steiner point is introduced by edge substitution to realize the update and maintenance of multicast tree.4.In this thesis,Java is used for simulation.Simulation results show that WRSMT algorithm can achieve effective Steiner minimum tree construction with lower tree cost compared with other algorithms in weighted network,which shows that the multicast tree construction algorithm designed in this thesis can effectively solve the problem of QoS-aware multicast routing for LEO satellites;the multicast tree management algorithm designed in this thesis can realize the local reconstruction of the Steiner minimum tree,and effectively support dynamic member management and fault recovery.