Research Of User Access Technology In GEO Satellite-terrestrial Networks

In recent years,the terrestrial mobile communication network has developed rapidly.However,the development of terrestrial mobile communication network will be restricted by economic cost and technology conditions,considering the factor of natural environment and population distribution.Thus,it is difficult to achieve seamless global coverage communication,and the invulnerability of the network is poor.The satellite mobile communication network has made up the shortcomings above of the terrestrial mobile communication network,but the high delay served by satellite also affects the quality of service.As a kind of comprehensive space heterogeneous network,GEO satellite-terrestrial communication network includes the terrestrial mobile communication network and satellite mobile communication network,which can provide high quality service for the users,and also can achieve global coverage.It plays an indispensable role in civil,military and disaster relief field.In GEO satellite-terrestrial communication networks,the GEO satellite remains relatively static to the ground,which can provide users with real-time services.Some delay sensitive users may cannot tolerate the high delay resulting from the long distance between satellite and terrestrial.Terrestrial communication network can provide users with services of low delay,but it can’t provide all users with services of high quality due to the two reasons,a.unbalanced load of the network caused by the inhomogeneous distribution of users,b.the rapid increase in user number.Therefore,GEO satellite-terrestrial communication networks should be used to balancing the load and deploying network resources for each user on the premise of ensuring the quality of services.A proper and high-efficient call admission control scheme is needed in this network.further more,caching technology could be introduced to this network,which could reduce transmission delay and bandwidth consumption.If the file applied by a user has already been cached in the BS or the satellite,there is no need to send request to core network or satellite.Thus,service time of users could be reduced to the minimal level,and the system efficiency will also be improved at the same time.This paper introduced the structure and characteristics of GEO satellite terrestrial network and studied the call admission control strategy in heterogeneous networks.A call admission control strategy based on the genetic algorithm were proposed in the network,which reduced the service delay by caching technology and optimized the resource allocation of the network while considering the users’ required channel bandwidth,maximum tolerated delay and the throughput of the network.After constructing the GEO satellite-terrestrial.network model and simulation,results show that higher system throughput can be achieved with the proposed scheme,while the QoS of users remains uninfluenced and the Call Blocking Probability(CBP)of the system is reduced efficiently,and the resource utilization is improved at the same time comparing to other call admission control strategy of heterogeneous network.