论文标题
RIS辅助室内多机器人通信系统的联合深入增强学习
Federated Deep Reinforcement Learning for RIS-Assisted Indoor Multi-Robot Communication Systems
论文作者
论文摘要
室内多机器人通信面临两个关键挑战：一个是由堵塞（例如墙壁）引起的严重信号强度降解，另一个是由机器人移动性引起的动态环境。为了解决这些问题，我们考虑可重构的智能表面（RIS）来克服信号阻塞并协助多个机器人之间的轨迹设计。同时，采用了非正交的多重访问（NOMA）来应对频谱的稀缺并增强机器人的连通性。考虑到机器人的电池能力有限，我们旨在通过共同优化接入点（AP）的发射功率，RIS的相移以及机器人的轨迹来最大化能源效率。开发了一种新颖的联邦深入强化学习（F-DRL）方法，以通过一个动态的长期目标来解决这个具有挑战性的问题。通过每个机器人计划其路径和下行链路功率，AP只需要确定RI的相移，这可以大大保存由于训练维度降低而导致的计算开销。仿真结果揭示了以下发现：i）与集中式DRL相比，提出的F-DRL可以减少至少86％的收敛时间； ii）设计的算法可以适应越来越多的机器人； iii）与传统的基于OMA的基准相比，NOMA增强方案可以实现更高的能源效率。
Indoor multi-robot communications face two key challenges: one is the severe signal strength degradation caused by blockages (e.g., walls) and the other is the dynamic environment caused by robot mobility. To address these issues, we consider the reconfigurable intelligent surface (RIS) to overcome the signal blockage and assist the trajectory design among multiple robots. Meanwhile, the non-orthogonal multiple access (NOMA) is adopted to cope with the scarcity of spectrum and enhance the connectivity of robots. Considering the limited battery capacity of robots, we aim to maximize the energy efficiency by jointly optimizing the transmit power of the access point (AP), the phase shifts of the RIS, and the trajectory of robots. A novel federated deep reinforcement learning (F-DRL) approach is developed to solve this challenging problem with one dynamic long-term objective. Through each robot planning its path and downlink power, the AP only needs to determine the phase shifts of the RIS, which can significantly save the computation overhead due to the reduced training dimension. Simulation results reveal the following findings: I) the proposed F-DRL can reduce at least 86% convergence time compared to the centralized DRL; II) the designed algorithm can adapt to the increasing number of robots; III) compared to traditional OMA-based benchmarks, NOMA-enhanced schemes can achieve higher energy efficiency.
