Access Selection Strategy And Bandwidth Allocation Algorithm In Space-Based Network

Nowadays, satellites are used for a variety of areas, including remote sensors, weather, navigation, geomatics, and communications. On one hand, the operation of BeiDou Navigation Satellite System(BDS) developed by China highlights the fact that China is expanding the deployment of spatial information infrastructure. On the other hand, China lacks of its own mobile satellite communication system, which means that China’s space information system is far from perfect. Aim to integrate existing satellite resources, design new satellite systems and achieve the maximum efficient use of space resources, China pioneered the concept of Integrated Spatial Information Network(ISIN). Most backbone nodes of ISIN are geostationary satellites, which, regardless of its routing function, should provide access to non-geostationary orbit satellites and earth station equipments. Therefore, access selection is one of the key issues to be solved. In addition, resources of satellite air interface are extremely precious, which certainly calls for a flexible and efficient bandwidth scheduling scheme in order to meet the QoS demands of users. The major contributions of this thesis are committed to addressing problems in these two areas. The main works and innovation points are as follows:1.In the thesis, the T criterion has been designed for non-geostationary orbit terminals to access to geostationary satellites. A T1criterion based geostationary satellite selection algorithm and a T2criterion based reselection algorithm have been proposed. Also, it’s been proved mathematically that the occurrence of any selection and re-selection event based on T criterion will increase the overall network utility. 2. As for the bandwidth allocation issue of satellite-ground downlink, a novel QoS statistic prediction based adaptive bandwidth allocation algorithm has been proposed. Due to the high propagation delay and deep fading of satellite-ground link, the QoS feedback information is easy to be invalid.This problem,in some extent, have been solved by adopting the least squares linear predictor. Simulation results showed that compared with the algorithm without QoS statistic prediction, the proposed algorithm can reduce the delay of real-time service by4to8ms.