In this paper, we consider a hybrid satellite-terrestrial network (HSTN) where a multiantenna satellite communicates with a ground user equipment (UE) with the help of multiple cache-enabled amplify-and-forward (AF) three-dimensional ($3$D) mobile unmanned aerial vehicle (UAV) relays. Herein, we employ the two fundamental most popular content (MPC) and uniform content (UC) caching schemes for two types of mobile UAV relays, namely fully $3$D and fixed height. Taking into account the multiantenna satellite links and the random $3$D distances between UAV relays and UE, we analyze the outage probability (OP) of considered system with MPC and UC caching schemes. We further carry out the corresponding asymptotic OP analysis to present the insights on achievable performance gains of two schemes for both types of $3$D mobile UAV relaying. Specifically, we show the following: (a) MPC caching dominates the UC and no caching schemes; (b) fully $3$D mobile UAV relaying outperforms its fixed height counterpart. We finally corroborate the theoretic analysis by simulations.

中文翻译：

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用于混合卫星-地面网络的 3 美元移动无人机缓存的中断性能

在本文中，我们考虑了一个混合卫星地面网络 (HSTN)，其中多天线卫星借助多个启用缓存的放大转发 (AF) 三维（$3$ D) 移动式无人驾驶飞行器 (UAV) 中继。在这里，我们为两种类型的移动无人机中继采用了两种基本的最流行内容 (MPC) 和统一内容 (UC) 缓存方案，即完全 $3$D 和固定高度。考虑到多天线卫星链路和 UAV 中继和 UE 之间的随机 $3$D 距离，我们分析了具有 MPC 和 UC 缓存方案的系统的中断概率 (OP)。我们进一步进行了相应的渐近 OP 分析，以展示对两种 3 美元移动无人机中继类型的两种方案可实现的性能提升的见解。具体来说，我们展示了以下内容：（a）MPC 缓存在 UC 中占主导地位，并且没有缓存方案；(b) 完全 3 美元的移动无人机中继性能优于固定高度的对应物。我们最终通过模拟验证了理论分析。