Future wireless networks, in particular, 5G and beyond, are anticipated to deploy dense Low Earth Orbit (LEO) satellites to provide global coverage and broadband connectivity with reliable data services. However, new challenges for interference management have to be tackled due to the large scale of dense LEO satellite networks. Rate-Splitting Multiple Access (RSMA), widely studied in terrestrial communication systems and Geostationary Orbit (GEO) satellite networks, has emerged as a novel, general, and powerful framework for interference management and multiple access strategies for future wireless networks. In this paper, we propose a multilayer interference management scheme for spectrum sharing in heterogeneous GEO and LEO satellite networks, where RSMA is implemented distributedly at GEO and LEO satellites, namely Distributed-RSMA (D-RSMA), to mitigate the interference and boost the user fairness of the system. We study the problem of jointly optimizing the GEO/LEO precoders and message splits to maximize the minimum rate among User Terminals (UTs) subject to a transmit power constraint at all satellites. A Semi-Definite Programming (SDP)-based algorithm is proposed to solve the original non-convex optimization problem. Numerical results demonstrate the effectiveness and network load robustness of our proposed D-RSMA scheme for multilayer satellite networks. Because of the data sharing and the interference management capability, D-RSMA provides significant max-min fairness performance gains when compared to several benchmark schemes.

翻译：未来无线网络，特别是5G及其演进，预计将部署密集的低地球轨道（LEO）卫星，以提供全球覆盖和宽带连接，并确保可靠的数据服务。然而，由于密集LEO卫星网络的大规模特性，必须应对干扰管理方面的新挑战。速率分割多址接入（RSMA）在地面通信系统和地球静止轨道（GEO）卫星网络中已得到广泛研究，并已成为一种新颖、通用且强大的框架，用于未来无线网络的干扰管理和多址接入策略。在本文中，我们提出了一种用于异构GEO和LEO卫星网络频谱共享的多层干扰管理方案，该方案在GEO和LEO卫星上分布式实施RSMA，即分布式RSMA（D-RSMA），以减轻干扰并提高系统的用户公平性。我们研究了联合优化GEO/LEO预编码器和消息分割的问题，以在所有卫星的发射功率约束下最大化用户终端（UT）中的最小速率。提出了一种基于半定规划（SDP）的算法来求解原始非凸优化问题。数值结果证明了我们提出的D-RSMA方案在多层卫星网络中的有效性和网络负载鲁棒性。由于数据共享和干扰管理能力，与几种基准方案相比，D-RSMA在最大化最小公平性方面提供了显著的性能增益。