Cellular-connected unmanned aerial vehicles (UAVs) operating in 5G New Radio (NR) macro networks experience severe and spatially non-uniform downlink interference. This is primarily caused by the interference from the sidelobes of downtilted base station (BS) antennas serving terrestrial users, which limits the ability of the network to provide uniform and high-quality coverage to aerial users. Supporting aerial users requires boosting the coverage of certain cells or sectors, which can further exacerbate inter-cell interference in dense macro deployments. This motivates the need for inter-cell interference coordination (ICIC) in multi-cell 5G NR networks serving both aerial and terrestrial users. In this work, we propose an ICIC framework that jointly optimizes antenna-domain coordination through BS uptilt angle optimization and time-domain interference coordination (TDIC) through NR-compliant scheduling. The framework is formulated as a multi-cell NR macro deployment problem that maximizes the minimum UAV signal-to-interference ratio (SIR) over a spatial grid of UAV locations while maintaining acceptable performance for ground user equipment (GUEs). The resulting optimization problem is non-convex and is solved using bio-inspired optimization techniques, including particle swarm optimization (PSO) and genetic algorithm (GA). Simulation results demonstrate that coordinated uptilt optimization with the booster-cell architecture significantly improves worst-case UAV SIR and downlink reliability in multi-cell 5G NR networks. booster-cell architecture significantly improves worst-case UAV SIR and downlink reliability in multi-cell 5G NR networks.

翻译：运行在5G新空口（NR）宏蜂窝网络中的蜂窝连接无人机（UAV）会经历严重且空间非均匀的下行链路干扰。这主要是由服务于地面用户的向下倾斜基站（BS）天线的旁瓣干扰所致，该干扰限制了网络为空中用户提供均匀高质量覆盖的能力。支持空中用户需增强特定小区或扇区的覆盖，而这在密集宏蜂窝部署中可能进一步加剧小区间干扰。因此，在同时服务于空中和地面用户的多小区5G NR网络中，亟需小区间干扰协调（ICIC）。本文提出了一种ICIC框架，该框架通过基站上仰角优化以实现天线域协调，并通过符合NR规范的调度实现时域干扰协调（TDIC）。该框架被建模为一个多小区NR宏蜂窝部署问题，其目标是在保持地面用户设备（GUE）可接受性能的前提下，最大化无人机位置空间网格上的最小无人机信干比（SIR）。该优化问题具有非凸性，并采用包括粒子群优化（PSO）和遗传算法（GA）在内的仿生优化技术求解。仿真结果表明，结合增强小区架构的协调上仰角优化显著改善了多小区5G NR网络中无人机的最差情况信干比及下行链路可靠性。