发表机构
Polytechnique Montreal（蒙特利尔高等理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对6G FR3频段空天地一体化网络，提出分层RIS关联框架，通过多对一匹配先关联地面RIS再关联空中RIS，最大化网络总和速率，显著优于贪婪和随机方案。
AI 中文摘要
多样化的第六代（6G）应用不断增长的需求要求高效的连接性、无缝的服务连续性和扩展的网络覆盖。尽管地面基础设施能够有效服务大多数无线用户设备（UE），但在偏远或受阻环境中，通信可靠性可能会显著降低。为应对这一挑战，本文提出了一种在上中频段（FR3）频谱中运行的可重构智能表面（RIS）辅助的空天地一体化网络（SAGIN）。所考虑的网络由一个地面基站（BS）、一个低地球轨道（LEO）卫星、多个地面RIS（TRIS）和无人机搭载的RIS（ARIS）组成，其中BS作为主要接入节点，而LEO卫星在地面链路不可用或无法满足所需服务质量（QoS）要求时提供补充连接。在此框架内，我们提出了一个分层RIS关联问题，以在RIS容量约束下最大化可实现网络总和速率。由于存在二元关联变量以及竞争有限RIS资源的UE之间的耦合，所得优化问题是一个混合整数非凸问题。为高效求解该问题，我们开发了一种基于分层多对一匹配的RIS关联框架。具体而言，具有满意地面连接性的UE首先与TRIS关联，而无法由地面网络可靠服务的UE随后通过非地面网络与ARIS关联。仿真结果表明，所提出的分层关联框架在可实现网络总和速率方面显著优于贪婪和随机关联方案。
英文摘要
The growing demand for diverse sixth-generation (6G) applications requires efficient connectivity, seamless service continuity, and extended network coverage. Although terrestrial infrastructures can effectively serve most wireless user equipment (UE), communication reliability may be significantly degraded in remote or blocked environments. To address this challenge, this paper proposes a reconfigurable intelligent surface (RIS)-assisted space-air-ground integrated network (SAGIN) operating in the upper mid-band (FR3) spectrum. The considered network consists of a terrestrial base station (BS), a low Earth orbit (LEO) satellite, multiple terrestrial RISs (TRISs), and unmanned aerial vehicle-mounted RISs (ARISs), where the BS serves as the primary access node, while the LEO satellite provides complementary connectivity when terrestrial links are unavailable or cannot satisfy the required quality-of-service (QoS) requirements. Within this framework, we formulate a hierarchical RIS association problem to maximize the achievable network sum rate under RIS capacity constraints. The resulting optimization problem is a mixed-integer nonconvex problem due to the binary association variables and the coupling among UEs competing for limited RIS resources. To efficiently solve the problem, we develop a hierarchical many-to-one matching-based RIS association framework. Specifically, UEs with satisfactory terrestrial connectivity are first associated with TRISs, whereas UEs that cannot be reliably served by the terrestrial network are subsequently associated with ARISs through the non-terrestrial network. Simulation results demonstrate that the proposed hierarchical association framework significantly outperforms greedy and random association schemes in terms of the achievable network sum rate.
