| 摘要: |
| 研究了智能反射面（RIS）和缓存辅助的无人机（UAV）中继通信系统方案,通过在UAV与用户之间搭建RIS反射信号,改善信道环境；在UAV与用户设备上部署缓存设备,预先存储热点内容,减轻无线回程链路的压力；以最大化用户服务成功概率为优化目标,建立缓存容量受限约束下的UAV与用户协同缓存放置策略优化模型,针对该非线性连续非凸约束优化问题,提出基于鲸鱼优化算法（WOA）的求解方法.仿真实验结果表明,使用RIS可以有效降低UAV通信中断概率,基于WOA的UAV与用户协同缓存最优放置策略优于现有其他两种缓存策略,能有效提高缓存命中概率,从而提高用户服务成功概率. |
| 关键词: 无人机（UAV）通信 协同缓存 智能反射面（RIS） 鲸鱼优化算法（WOA） 服务成功概率 |
| DOI：10.3969/J.ISSN.1000-5137.2024.03.005 |
| 分类号:TN925+.3 |
| 基金项目: |
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| Cooperative caching strategy of UAV and user with RIS-assisted |
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ZHU Jingfa, SU Ying, ZHANG Jing
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College of Information, Mechanical and Electrical Engineering, Shanghai Normal University, Shanghai 201418, China
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| Abstract: |
| A reconfigurable intelligent surface （RIS） and cache-assisted unmanned aerial vehicle（UAV） relay-assisted communication system scheme was investigated to improve the channel environment by building RIS reflective signals between the UAV and the user. By deploying cache devices to pre-store hotspot contents on the UAV and user devices, the pressure on the wireless backhaul link was reduced. Besides the cache capacity-constrained optimization model for the cooperative cache placement policy between drones and users with maximizing the user service success probability as the optimization objective was established, and a problem solving method based on the whale optimization algorithm （WOA） was proposed for this nonlinear continuous non-convex constrained optimization problem. The simulation results showed that the use of RIS could effectively reduce the UAV communication outage probability, and the optimal placement policy of UAV-user collaborative cache based on WOA algorithm performed better than the other two existing caching policies, which could effectively improve the cache hit probability and thus the user service success probability. |
| Key words: unmanned aerial vehicle （UAV） communication cooperative caching reconfigurable intelligent surface （RIS） whale optimization algorithm （WOA） service success probability |
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