Driven by both technological development and practical demands, the low-altitude economy relying on low-altitude aircrafts (LAAs) is booming. However, neither satellites nor terrestrial fifth-generation (5G) networks alone can effectively satisfy the communication requirements for ubiquitous lowaltitude coverage. While full integration of satellites and 5G networks offers theoretical benefits, the associated overhead and complexity pose significant challenges for rapid deployment. As a more economical and immediately viable alternative, this paper investigates partially-integrated networks where satellites and 5G systems operate with coarse synchronization yet achieve coordinated spectrum sharing, pooling their capabilities to jointly serve LAAs. Leveraging the inherent position-awareness of LAAs, we propose a framework for joint time-frequency spectrum sharing with an adaptive synchronization time scale, where only large-scale channel state information (CSI) is required. To avoid solving the NP-hard optimization problem directly, link-feature-aided clustering is employed following a divide-andconquer strategy. The proposed framework achieves substantial performance gains with low overhead and complexity, enabling swift advancement of low-altitude applications while paving the way for future integrated satellite-terrestrial network evolution.

翻译：在技术发展与实际需求的双重驱动下，依赖低空飞行器的低空经济正蓬勃发展。然而，无论是卫星还是地面第五代网络，均无法单独有效满足无处不在的低空覆盖通信需求。尽管卫星与5G网络的完全融合在理论上具有优势，但其带来的开销与复杂性给快速部署带来了重大挑战。作为一种更经济且立即可行的替代方案，本文研究了一种部分融合的网络架构：卫星与5G系统通过粗粒度同步实现协同频谱共享，整合双方能力以共同服务低空飞行器。利用低空飞行器固有的位置感知能力，我们提出了一种具有自适应同步时间尺度的联合时频频谱共享框架，该框架仅需大规模信道状态信息。为避免直接求解这一NP难优化问题，我们采用分治策略，实施了基于链路特征辅助的聚类方法。所提框架以较低的开销和复杂度实现了显著的性能增益，既能推动低空应用的快速发展，也为未来空天地一体化网络的演进铺平了道路。