High Altitude Platform Stations (HAPS) have emerged as a promising enabler for next-generation wireless networks, offering ubiquitous connectivity to ground users. Operating either in standalone mode or in integration with terrestrial networks, HAPS can significantly enhance both coverage and capacity due to their strategic placement in the stratosphere. However, interference management in HAPS-empowered networks requires special attention due to the unique propagation characteristics of HAPS links. In particular, the strong line-of-sight (LoS) conditions between HAPS and ground users result in limited channel variability, thereby intensifying inter-user interference. In this work, we consider a single HAPS serving multiple ground users through multiple beams over a limited number of orthogonal resource blocks (RBs). To address the resulting interference, we propose a novel angular-aware user clustering and interference-aware RB allocation framework that strategically clusters users, designs beams to serve each cluster, and allocates RBs to users across clusters. To further mitigate intra-RB interference, a rate-splitting multiple access (RSMA) scheme is incorporated. Simulation results demonstrate that the proposed clustering and RSMA-based approach significantly outperforms baseline schemes in terms of achievable per-user spectral efficiency.

翻译：高空平台站（HAPS）已成为下一代无线网络中有前景的赋能技术，为地面用户提供泛在连接。无论以独立模式运行还是与地面网络集成，HAPS因其位于平流层的战略位置，可显著增强覆盖范围和容量。然而，由于HAPS链路的独特传播特性，HAPS赋能网络中的干扰管理需要特别关注。具体而言，HAPS与地面用户之间强烈的视距（LoS）条件导致信道变化有限，从而加剧了用户间干扰。本研究考虑单个HAPS通过有限数量的正交资源块（RB）上的多波束服务多个地面用户。为应对由此产生的干扰，我们提出了一种新颖的角度感知用户聚类和干扰感知RB分配框架，该框架通过战略性地聚类用户、设计服务于每个聚类的波束，并跨聚类为用户分配RB。为进一步缓解RB内干扰，引入了速率分割多址接入（RSMA）方案。仿真结果表明，所提出的基于聚类与RSMA的方法在可实现每用户频谱效率方面显著优于基准方案。