| In the recent years,the development of satellite communication is notable,mainly because of its wide coverage area,large bandwidth capacity,and supporting multiple multimedia services through fixed and mobile infrastructures.Among them,the development of LEO satellite communication is most significant,mainly because the LEO satellite has the characteristics of flexible networking,low transmission delay and seamless global coverage.Although the low orbit satellite communication has many advantages,there are also problems such as shortage of spectrum resources,handover frequently and so on.Velocity of low earth orbit satellite is very fast,it will cause the subscriber station handover frequently.As to the admission control problem of the low satellite to subscriber station,this paper proposes that it is based on admission control strategy of the degradation of subscriber station,and introduce the dynamic channel reservation strategy as well as services prediction strategy.Ensure that the degradation of rationality,and improve the success rate of subscriber station handover as well as reduce the new call blocking rate.As to the admission control of subscriber station to users,this paper refers to the frame of degradation strategy of the ground cellular network,and combines the characteristics of LEO satellite communication,revising the frame.The services bandwidth degradation strategy also has some disadvantages.Although the services bandwidth degradation increases the system capacity which will bring some positive gains for the subscriber station,while which also will affect the user experience,thereby affecting the degree of user satisfaction.Therefore,degradation strategy will also bring negative cost to the user station.As to these two conflict factors,this paper proposes a cost function that can describe the net profit obtained from the bandwidth degradation and call admission strategy.Through the Lagrange multiplier method,we can calculate the maximum net profit that the user station obtains,and at the same time,the user station can also get reasonable bandwidth degradation and admission control scheme. |
