In this paper, we develop a hierarchical aerial computing framework composed
of high altitude platform (HAP) and unmanned aerial vehicles (UAVs) to compute
the fully offloaded tasks of terrestrial mobile users which are connected
through an uplink non-orthogonal multiple access (UL-NOMA). In particular, the
problem is formulated to minimize the AoI of all users with elastic tasks, by
adjusting UAVs trajectory and resource allocation on both UAVs and HAP, which
is restricted by the channel state information (CSI) uncertainty and multiple
resource constraints of UAVs and HAP. In order to solve this non-convex
optimization problem, two methods of multi-agent deep deterministic policy
gradient (MADDPG) and federated reinforcement learning (FRL) are proposed to
design the UAVs trajectory and obtain channel, power, and CPU allocations. It
is shown that task scheduling significantly reduces the average AoI. This
improvement is more pronounced for larger task sizes. On the one hand, it is
shown that power allocation has a marginal effect on the average AoI compared
to using full transmission power for all users. On the other hand, compared
with traditional transmissions (fixed method) simulation result shows that our
scheduling scheme has a lower average AoI.

用空中计算框架由高空平台和无人机组成，解决通过上行非正交多址接入连接的移动用户的任务完全卸载问题，通过调整无人机轨迹和资源分配来最小化用户的数据时延，使用多智能体深确定策略梯度和联邦强化学习两种方法优化求解，显示任务调度显著降低了数据时延。