The interconnection of 5G and non-terrestrial networks (NTNs) has been actively studied to expand connectivity beyond conventional terrestrial infrastructure. In the 3GPP standardization of 5G systems, the 5G Quality of Service (QoS) Identifier (5QI) is defined to characterize the QoS requirements of different traffic requirements. However, it falls short in capturing the diverse latency, capacity, and reliability profiles of NTN environments, particularly when NTNs are used as backhaul. Furthermore, it is difficult to manage individual traffic flows and perform efficient resource allocation and routing when a large number of 5G traffic flows are present in NTN systems. To address these challenges, we propose an optimization framework that enhances QoS handling by introducing an NTN QoS Identifier (NQI) and grouping 5G traffic into NTN slices based on similar requirements. This enables unified resource control and routing for a large number of 5G flows in NTN systems. In this paper, we present the detailed procedure of the proposed framework, which consists of 5QI to NQI mapping, NTN traffic to NTN slice mapping, and slice-level flow and routing optimization. We evaluate the framework by comparing multiple mapping schemes through numerical simulations and analyze their impact on overall network performance.

翻译：为扩展传统地面基础设施之外的连接能力，5G与非地面网络（NTN）的互联已受到广泛研究。在3GPP的5G系统标准化中，定义了5G服务质量（QoS）标识符（5QI）以表征不同业务需求的QoS要求。然而，该标识符难以准确描述NTN环境中多样化的时延、容量与可靠性特征，尤其当NTN被用作回传链路时。此外，当NTN系统中存在大量5G业务流时，管理单个业务流并执行高效的资源分配与路由选择具有挑战性。为解决这些问题，本文提出一种优化框架，通过引入NTN QoS标识符（NQI）并将具有相似需求的5G业务聚合至NTN切片中，从而增强QoS处理能力。该框架实现了对NTN系统中大量5G流的统一资源控制与路由管理。本文详细阐述了所提框架的实施流程，包括5QI至NQI的映射、NTN业务至NTN切片的映射，以及切片级的流量与路由优化。我们通过数值仿真对比多种映射方案，评估该框架的性能，并分析其对整体网络性能的影响。