Space-ground Cooperative Transmission Based On SDN

As human activities gradually extend from inland to desert mountains,deep oceans,and the vast universe,it becomes more and more important to integrate satellite and ground networks for cooperative transmission among them.The satellite-ground integrated network consists of a variety of satellite networks(such as satellite systems for communications,remote sensing,and navigation)located at high,medium,and low orbits and ground networks(Internet,mobile communication networks 3G/4G et al.).The resulting integrated network can easily provide communication coverage for areas inaccessible by the Internet and mobile communication networks.The satellite-ground integration network will not only play an irreplaceable role in key applications such as emergency rescue and ocean-going cruise,but also can serve mobile users in airplanes and high-speed trains.Providing uninterrupted network and information services during high-speed sports has become an indispensable information infrastructure in social development and human life.In order to improve the overall efficiency of the satellite-ground network,it is necessary to integrate advantages of the satellite networks and ground networks.The goal is to make full use of network resources at all levels,especially limited satellite resources,by means of functionally reconfigurable network management and satellite-ground cooperative transmission.However,the existing work focuses on how to interconnect satellites and ground networks,and lacks of controllable management and cooperative scheduling of networked resources.Aiming at solving the above problems,this paper focuses on the organic integration of satellite and ground network structures and the satellite-ground cooperative transmission.It designs a software-defined satellite-ground integrated network architecture with efficient network management abilities,and proposes a model and an approach for satellite-ground cooperative transmission,which significantly improve comprehensive transmission capabilities of satellite and ground networks.The main work and contributions of this paper are summarized as follows.· It designed a software-defined satellite-ground integrated network architecture.Considering the architecture heterogeneity and the resource limitation of satellite and ground networks,this paper designed a satellite-ground network architecture with programmable management,based on the policy of regional controlling and inter-domain cooperation.This architecture can provide on-demand controlling and cooperation for autonomous satellite-ground networks,and can efficiently manage various network resources.As a result,it plays an architecture role for satellite-ground cooperative transmission,with significant capability improvements.· It proposed a mathematical model for satellite-ground cooperative transmission.This model quantitatively describes the problem of optimization of space-to-space dynamic network capacity in the context of stereoscopic transmission of high,medium and low orbit satellite networks and ground networks.It describes the upper bound of cooperative transmission among satellite-ground integrated networks.· It proposed a satellite-ground cooperative transmission algorithm that can adapt to dynamical network environment and workload.Firstly,taking into account the long transmission delay and high bit error rate of inter-satellite links compared to links of ground networks,a quantitative evaluation model for satellite-ground cooperative transmission,based on characteristics of links,and workload states of links and nodes,is proposed.Then,an efficient multi-path stereoscopic routing algorithm that can adapt to network conditions and loads is developed.Through controller-level intra-domain scheduling and super controller-level inter-domain scheduling,different granularities of network traffic balance can be achieved.Finally,this paper designed an algorithm that dynamically assigns traffic among multiple satellite-ground path in the load-balanced way.To evaluate the proposed approach,a simulation system with multi-level network management for satellite-ground integrated networks was developed,followed by a number of performance comparisons with the related proposals QSR(Qo S-oriented Satellite Routing)and MVA(Mean Value Analysis).The results demonstrate that the solution proposed in this paper significantly improves network throughput,end-to-end delay,transmission quality and load balancing.