Design And Implementation Of SDN Controller For Oneweb Satellite Network

With the continuous breakthrough of broadband satellite communication systems and space network technology,the era of satellite communication entering the Internet application has changed from ideal to reality.Low-orbit satellites will play an important role in the future development of 5G and even 6G.The Software Defined Network(SDN)has three major advantages of control forwarding separation,open programming interface and centralized control,which provide new ideas for the future development of low-orbit satellite networks.Firstly,based on the development status of the SDN-based space network system,this paper analyzes the various problems faced by the low-orbit satellite network represented by OneWeb under the existing traditional satellite network architecture,and the idea of SDN The organic integration with the spatial information network can effectively solve the problems of network management difficulty and limited network resources,and bring new opportunities for the future development of the space network.Secondly,the SDN-based OneWeb system network architecture is designed.The advantages of applying SDN to OneWeb low-orbit satellite network are analyzed.The function of various parts such as system ground station and OneWeb satellite are introduced in detail.On the basis of the above,the controller system is designed,and this paper focuses on the discussion of the deployment mode of the controller,the modular design and the choice of the southbound protocol,so that the controller can be applied to the space network environment suitably;Then the basic module in the controller is analyzed,and the link discovery,routing function and switching function module are designed.Based on the POX controller,an improved SDN controller for this paper is realized.Then,for the routing module,this paper compares two different topology virtualization methods and then chooses to use the network topology time virtualization-based routing method;use the network simulation software Mininet and the designed improved POX controller to compare the shortest path algorithm and The end-to-end throughput of the Ecmp algorithm is based on the Ecmp algorithm-based end-to-end throughput optimization algorithm for the possible link instability of the inter-satellite link.The effectiveness and reliability of the algorithm are verified.Finally,for the handover function,the Mininet-Wifi is used to simulate the hard handover process of the OneWeb satellite to the ground base station.A hard handoff algorithm based on the flow table in advance is proposed.Experiments show that the proposed algorithm can reduce the handover delay and packet loss rate of the satellite to the ground base station to some extent.