In this paper, we explore the problem of utilizing Integrated Access and Backhaul (IAB) technology in Non-Terrestrial Networks (NTN), with a particular focus on aerial access networks. We consider an Uncrewed Aerial Vehicle (UAV)-based wireless network comprised of two layers of UAVs: (a) a lower layer consisting a number of flying users and a UAV Base Station (BS) that provides coverage for terrestrial users and, (b) an upper layer designated to provide both wireless access for flying users and backhaul connectivity for UAV BS. By adopting IAB technology, the backhaul and access links collaboratively share their resources, enabling aerial backhauling and the utilization of the same infrastructure and frequency resources for access links. A sum-rate maximization problem is formulated by considering aerial backhaul constraints to optimally allocate the frequency spectrum between aerial and terrestrial networks. We decompose the resulting non-convex optimization problem into two sub-problems of beamforming and spectrum allocation and then propose efficient solutions for each. Numerical results in different scenarios yield insightful findings about the effectiveness of using the IAB technique in aerial networks.

翻译：本文探讨了在非地面网络中应用集成接入与回传技术的问题，特别聚焦于空中接入网络。我们构建了一个基于无人机的双层无线网络架构：(a) 下层由若干飞行用户和为地面用户提供覆盖的无人机基站组成；(b) 上层专门为飞行用户提供无线接入，同时为无人机基站提供回传连接。通过采用集成接入与回传技术，回传链路与接入链路可协同共享资源，实现空中回传功能，并利用相同的基础设施与频段资源服务接入链路。本研究通过考虑空中回传约束条件，构建了空-地网络频谱资源优化分配的和速率最大化问题。我们将由此产生的非凸优化问题分解为波束成形和频谱分配两个子问题，并针对每个子问题提出了高效解决方案。不同场景下的数值仿真结果揭示了集成接入与回传技术在空基网络中的有效性。