Contents I. Introduction
With the rapid development of social economy and communication technology in recent years, it is difficult to meet the increasing communication demand only relying on the terrestrial communication network [1]. The low Earth orbit (LEO) satellite network has become indispensable to the communication system because it can effectively bridge the coverage gap of the terrestrial networks [2]. However, the available resources are becoming increasingly scarce. How to ensure the performance of network while achieving system capacity expansion is the key issue to be solved urgently. Meanwhile, the diversified services show a high degree of concurrency and flexibility under the cross-domain distribution, which makes the reasonable allocation method of resources become the bottleneck to improve the performance of network [3]. In order to improve the system capacity, the non-orthogonal multiple access (NOMA) [4] is introduced into 5G communication. However, the traditional resource allocation methods are not fully applicable to NOMA.
