[论文解读] UAV-Aided Cellular Offloading: A Potential Solution to Hot-Spot Issue in 5G

Jiangbin Lyu, Yong Zeng+1 more|arXiv (Cornell University)|May 25, 2017

UAV Applications and Optimization被引用 5

一句话总结

本文提出了一种无人机辅助的混合蜂窝网络，利用空中基站对5G热点区域的小区边缘用户进行流量卸载。通过在正交和共享频谱接入下联合优化无人机轨迹、带宽分配和用户分组，该方案显著提升了最小用户吞吐量和频谱效率，相较于传统网络表现更优，且频谱复用在付出轻微复杂度代价的情况下进一步提升了性能。

ABSTRACT

In conventional terrestrial cellular networks, mobile terminals (MTs) at the cell edge often pose a performance bottleneck due to their long distances from the serving ground base station (GBS), especially in hotspot period when the GBS is heavily loaded. This paper proposes a new hybrid network architecture by leveraging the use of unmanned aerial vehicle (UAV) as an aerial mobile base station, which flies cyclically along the cell edge to offload data traffic for cell-edge MTs. We aim to maximize the minimum throughput of all MTs by jointly optimizing the UAV's trajectory, bandwidth allocation and user partitioning. We first consider orthogonal spectrum sharing between the UAV and GBS, and then extend to spectrum reuse where the total bandwidth is shared by both the GBS and UAV with their mutual interference effectively avoided. Numerical results show that the proposed hybrid network with optimized spectrum sharing and cyclical multiple access design significantly improves the spatial throughput over the conventional GBS-only network; while the spectrum reuse scheme provides further throughput gains at the cost of slightly higher complexity for interference control. Moreover, compared to the conventional small-cell offloading scheme, the proposed UAV offloading scheme is shown to outperform in terms of throughput, besides saving the infrastructure cost.

研究动机与目标

• 解决在高负载5G网络中由小区边缘用户引起的性能瓶颈问题。
• 与传统小型基站部署相比，降低回传和基础设施成本。
• 通过联合优化最大化所有移动终端中的最小吞吐量。
• 评估无人机与地面基站之间正交接入和频谱复用共享策略的性能。

提出的方法

• 提出一种混合网络架构，将无人机作为空中移动基站，沿小区边缘周期性飞行。
• 通过优化无人机轨迹、带宽分配和用户分组以最大化最小用户吞吐量。
• 首先对正交多址接入（OMA）下的系统进行建模，随后扩展至非正交频谱复用并引入干扰抑制机制。
• 通过联合优化轨迹与资源分配，实现负载均衡并提升公平性。
• 采用干扰感知设计，以管理频谱复用场景下的相互干扰。

实验结果

研究问题

• RQ1 与仅依赖地面基站的传统网络相比，无人机辅助卸载在提升最小用户吞吐量方面表现如何？
• RQ2 无人机与地面基站之间实现频谱复用可带来多大性能增益？
• RQ3 所提出的轨迹与资源分配联合优化方案与传统小型基站卸载相比，在吞吐量和成本方面表现如何？
• RQ4 在频谱复用中，频谱效率增益与系统复杂度之间存在何种权衡？

主要发现

• 所提出的无人机辅助网络相较于传统仅依赖地面基站的网络，显著提升了空间吞吐量。
• 与正交接入相比，频谱复用提供了额外的吞吐量增益，尽管干扰管理复杂度略有上升。
• 无人机轨迹、带宽和用户分组的联合优化可最大化最小用户吞吐量，从而提升公平性。
• 无人机卸载方案在吞吐量和基础设施成本效率方面均优于传统小型基站卸载方案。