Cellular-connected unmanned aerial vehicles (UAVs) in 5G NR networks experience propagation and interference conditions that vary significantly with altitude and differ substantially from those experienced by terrestrial users. This is primarily caused by the down-tilted antenna sectors in 5G NR networks, which cause UAVs to be served (and interfered with) by the sidelobes. In this paper, we develop a 3GPP-compliant system-level framework for the consistent characterization of key performance indicators (KPIs) such as reference signal received power (RSRP), reference signal received quality (RSRQ), and signal-to-interference-and-noise ratio (SINR) in a multi-site tri-sector deployment with realistic antenna patterns and probabilistic models for line-of-sight (LOS) and non-LOS (NLOS) conditions. Simulation results demonstrate that a critical transition for aerial users is experienced when going from coverage-limited to interference-limited conditions at higher altitudes. Although RSRP is affected by large-scale propagation characteristics and degrades gradually with increasing altitude and inter-site distance (ISD), SINR degrades much faster due to increased interference caused by LOS conditions. On the contrary, increasing ISD improves SINR and RSRQ due to lower interference, even as received power is reduced.

翻译：蜂窝连接的5G NR网络无人机所经历的传播和干扰条件随高度显著变化，且与地面用户情况存在本质差异。这主要源于5G NR网络天线扇区的下倾设计，导致无人机通过旁瓣获得服务（并遭受旁瓣干扰）。本文建立了一个符合3GPP标准的系统级框架，用于在多站点三扇区部署场景中，结合真实天线方向图及视距与非视距条件的概率模型，一致性表征参考信号接收功率、参考信号接收质量及信干噪比等关键性能指标。仿真结果表明，当空中用户在较高海拔从覆盖受限状态过渡到干扰受限状态时，将经历关键性转变。虽然RSRP受大尺度传播特性影响且随高度及站间距增加而逐渐下降，但SINR因视距条件导致的干扰增强而急剧恶化。相反，增大ISD可通过降低干扰来改善SINR和RSRQ，即便接收功率有所下降。