Research On Constellation Design And User Access Algorithm Of Double-layered Satellite Networks

In order to compensate for the shortcomings of the single-satellite network,hybrid satellite networks are proposed, and this kind of network contains theadvantages of single-satellite network and can provide users with a better quality ofservice. There are many kinds of forms of hybrid satellite networks, and they are allmade of multiple satellites. The fact that one certain user is covered by severalsatellites makes the satellite access algorithm much important to the performance ofhybrid satellite networks. Every algorithm has different impact on the quality ofservice so many current researches focus on how to design better hybrid satellitenetworks and satellite access method. Based on the analysis of the characteristics ofhybrid satellite networks, we designed a5GEO+66LEO double-layered satellitenetwork and a satellite access algorithm with multiple QoS constraints is proposedin this paper. This paper contains the following parts:Firstly, the structure of hybrid satellite networks and satellite access algorithmare analyzed in this paper. And based on this understanding of the advantages anddisadvantages of each orbit satellite network layer, the shortcomings of singlesatellite network is described and the advantages of hybrid satellite networks isexplored. Moreover, we briefly introduce the existing hybrid satellite networks, andits network topology is analyzed. Then according to the results of simulation,typical satellite access algorithms are investigated.Secondly, after analyzing the characteristics of the GEO, MEO, LEO and HEOsatellite networks and comparing their performance and complexity, a double5GEO+66LEO satellite network is designed in this paper. In this network, GEO and LEOcan make up for each other's shortcomings. In addition, the technology of GEOsatellite is mature and LEO satellites are easy to implement, which makes it easy torealize this network. After that, we built this satellite network model with STK andanalyze its visibility, covering properties and inter-satellite link characteristics.Finally, typical satellite access algorithms are compared and summarized.These algorithms are focusing on satellites and analyzing the covering time of user,the distance and the load of user to select the appropriate satellite to access.Therefore, these typical algorithms are lack of the consideration of quality ofservice. However, in this paper we focus on users, we measure the differencebetween the requirement of users and the service satellites can provide to choose thesatellite whose degree of difference is the smallest. So a satellite selection algorithmwith multiple QoS constraints is proposed in this paper, and according to simulation the correctness of this algorithm is verified. Moreover, the comparison of thisalgorithm and the typical satellite access algorithm shows that it can reduce newcall blocking rate, handover failure probability and forced outage probability whileincreasing the average load of network, so this algorithm can improve theperformance of network access.