论文标题
集成了混合FSO/RF非事物网络的LEO卫星和多UAV强化学习
Integrating LEO Satellites and Multi-UAV Reinforcement Learning for Hybrid FSO/RF Non-Terrestrial Networks
论文作者
论文摘要
低空地轨道（LEO）卫星（SATS）和新兴无人驾驶飞机（UAV）的巨型构造是在超越第五代（5G）系统中高速和长距离通信的有希望的推动者。在本文中，将SAT和无人机集成在非晶体网络（NTN）中，我们研究了使用SAT和UAV继电器在两个遥远的地面终端之间转发数据包的问题，该问题使用毫米波（MMWAVE）射频频率（RF）或自由空间（RF）或自由空间（FSO）链接。为了最大程度地提高沟通效率，应使用适当的FSO/RF链接来优化与轨道SAT的实时关联以及无人机的移动轨迹，由于时间变化的网络拓扑以及大量可能的控制动作，这具有挑战性。为了克服困难，我们将这个问题提高到具有新颖的动作维度降低技术的多代理深度加固学习（MARL）。模拟结果证实了我们提出的SAT-UAV综合方案与具有固定地面继电器的基准方案相比，端到端总和吞吐量更高1.99倍。在改善吞吐量的同时，我们提出的方案还旨在减少无人机控制能量，比仅最大化吞吐量的基线方法，能量效率高2.25倍。 Lastly, thanks to utilizing hybrid FSO/RF links, the proposed scheme achieves up to 62.56x higher peak throughput and 21.09x higher worst-case throughput than the cases utilizing either RF or FSO links, highlighting the importance of co-designing SAT-UAV associations, UAV trajectories, and hybrid FSO/RF links in beyond-5G NTNs.
A mega-constellation of low-altitude earth orbit (LEO) satellites (SATs) and burgeoning unmanned aerial vehicles (UAVs) are promising enablers for high-speed and long-distance communications in beyond fifth-generation (5G) systems. Integrating SATs and UAVs within a non-terrestrial network (NTN), in this article we investigate the problem of forwarding packets between two faraway ground terminals through SAT and UAV relays using either millimeter-wave (mmWave) radio-frequency (RF) or free-space optical (FSO) link. Towards maximizing the communication efficiency, the real-time associations with orbiting SATs and the moving trajectories of UAVs should be optimized with suitable FSO/RF links, which is challenging due to the time-varying network topology and a huge number of possible control actions. To overcome the difficulty, we lift this problem to multi-agent deep reinforcement learning (MARL) with a novel action dimensionality reduction technique. Simulation results corroborate that our proposed SAT-UAV integrated scheme achieves 1.99x higher end-to-end sum throughput compared to a benchmark scheme with fixed ground relays. While improving the throughput, our proposed scheme also aims to reduce the UAV control energy, yielding 2.25x higher energy efficiency than a baseline method only maximizing the throughput. Lastly, thanks to utilizing hybrid FSO/RF links, the proposed scheme achieves up to 62.56x higher peak throughput and 21.09x higher worst-case throughput than the cases utilizing either RF or FSO links, highlighting the importance of co-designing SAT-UAV associations, UAV trajectories, and hybrid FSO/RF links in beyond-5G NTNs.
