Equipped with base station hardware, unmanned aerial vehicles (UAVs) can act as drone small cells (DSCs) to complement the traditional terrestrial small cells (TSCs) in providing ubiquitous connectivity for a wide range of applications. Although the performance of drone-assisted heterogeneous networks has been investigated, the state-of-the-art adopts simplified channel models that are not applicable to practical network scenarios. To make an accurate analysis on the network performance, and provide guidelines for the practical design of cell association and network deployment strategy, in this work, we consider a drone-assisted heterogeneous network that employs a flexible biased cell association policy and adopts a more general channel model that incorporates line-of-sight (LoS) and non-line-of-sight (NLoS) components for both air-to-ground (ATG) and ground-to-ground (GTG) transmissions. We develop a unifying analytical framework to evaluate the network performance in terms of coverage probability, area spectral efficiency (ASE) and user throughput. Our results show that 1) deploying DSCs to complement traditional TSCs can only deteriorate the network performance within the ultra-dense network region, 2) by optimally setting the bias factor for cell association policy, the network performance can be further enhanced.

中文翻译：

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无人机辅助异构网络的性能分析和单元关联设计


配备基站硬件的无人机（UAV）可以充当无人机小型基站（DSC），以补充传统的地面小型基站（TSC），为各种应用提供无处不在的连接。尽管已经研究了无人机辅助异构网络的性能，但最先进的技术采用了简化的信道模型，不适用于实际的网络场景。为了对网络性能进行准确分析，并为小区关联和网络部署策略的实际设计提供指导，在这项工作中，我们考虑了一种无人机辅助异构网络，该网络采用灵活的偏置小区关联策略并采用更通用的方法信道模型，包含用于空对地 (ATG) 和地对地 (GTG) 传输的视距 (LoS) 和非视距 (NLoS) 组件。我们开发了一个统一的分析框架来评估覆盖概率、区域频谱效率（ASE）和用户吞吐量方面的网络性能。我们的结果表明，1）部署DSC来补充传统TSC只会恶化超密集网络区域内的网络性能，2）通过优化设置小区关联策略的偏置因子，可以进一步增强网络性能。