Research On Handover Strategy For The Space-Ground-Integrated Network

With the increasing of constantly developing demands for national security,Aeronautics and Astronautics,emergency rescue,etc.In recent years,the space-ground-integrated network is highly concerned as one of the significant solutions.Space-ground-integrated network is based on the terrestrial network and supplemented by the space network,covering multiple types of networks.The construction of global space-ground-integrated network offers comprehensive support for air-sea-land communication,weather forecasting,resource prospection,emergency rescue,etc.The heterogeneous,dynamic and diverse network structure characteristics of the space-ground-integrated network especially in case of Low Earth Orbit(LEO)satellite networks contributes to frequently satellite handover due to the fast velocity relative to the earth.In this case,a secure and efficient handover mechanism can be particularly important.This paper takes the inter-satellite handover of low-orbit satellites in the space-based network of the space-ground-integrated network as the research starting point,and conducts two researches on handover technology.(1)In order to solve the problem of target satellite selection when handover is triggered,this paper proposes a multi-attribute satellite handover decision algorithm.Considering various factors which affect handover performance,this algorithm transforms the target selection problem into a multi-attribute decision-making problem.The proposed algorithm calculates the weight of each attribute through combination weighting,and ranks the candidate satellites by TOPSIS(Technique for Order Preference by Similarity to an Ideal Solution).Finally,it selects the best satellite from multiple candidate satellites as the handover target.The simulation experiment results verify the effectiveness of the proposed algorithm in handover times and average blocking compared with other handover strategies.(2)To solve the frequent handover problem of satellite access nodes due to its high-speed motion,this paper proposes a context-based secure handover mechanism.This approach applies identity-based cryptography for key management in the entire system,and its context mechanism transmits the authentication information of the specific mobile node in advance to the next satellite access node.The experimental results show that the proposed scheme improves the handover performance.