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计算机工程

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SAG-MEC网络下支持WPT的无人机动态任务卸载与资源分配

  • 发布日期:2024-12-05

Dynamic task unloading and resource allocation of UAVs supported by WPT in SAG-MEC network

  • Published:2024-12-05

摘要: 针对偏远地区蜂窝网络覆盖不足且物联网(IoT)设备能量和计算能力低,从而无法满足大量延迟敏感型任务卸载和计算需求的问题,考虑将空天地一体化网络(Space-Air-Ground Integrated Network, SAGIN)和移动边缘技术(mobile edge computing,MEC)相结合,并提出了一种支持无线供电(Wireless Power Transmission,WPT)技术的无人机辅助IoT设备的动态任务卸载和资源分配策略,其中无人机负责收集IoT设备产生的计算密集型任务,然后采用部分卸载模式将这些任务根据当前状态进行本地计算或动态卸载给基站和LEO卫星进一步处理。由于动态的异构网络和长期排队延迟与短期决策的耦合性,因此在排队延迟的约束下提出了一种基于Lyapunov优化的双延迟深度确定性策略梯度(Twin Delayed Deep Deterministic Policy Gradient,TD3PG)算法,该算法通过优化无人机动态关联、任务分配、计算资源分配和带宽分配来协调无人机学习最优卸载策略和资源分配。仿真结果表明,所提出的动态方案与其他对比方案相比能够有效降低无人机网络的能耗、网络积压总和及平均排队延迟,其次在不同学习率组合下,TD3PG算法相对于DDPG算法和DDQN算法的奖励分别提高了13.6%、24%和20.4%、17.9%。

Abstract: Addressing the problem of insufficient cellular network coverage and low energy and computing power of Internet of Things (IoT) devices in remote areas, which cannot meet the large number of delay-sensitive task offloading and computing, Considering the combination of Space-Air-Ground Integrated Network (SAGIN) and mobile edge computing (MEC), It also proposes a strategy for dynamic task offloading and resource allocation of UAV-assisted IoT devices that support Wireless Power Transmission (WPT) technology, in which UAVs are responsible for collecting compute-intensive tasks generated by IoT devices. These tasks are locally calculated or dynamically unloaded to the base station and LEO satellite for further processing by using the partial unloading mode according to the current state. Due to the dynamic heterogeneous network and the coupling of long-term queuing delay and short-term decision making, Therefore, under the constraint of queuing delay, a Twin Delayed Deep Deterministic Policy Gradient (TD3PG) algorithm based on Lyapunov optimization is proposed. The algorithm coordinates UAVs learning optimal unloading strategy and resource allocation by optimizing UAVs dynamic association, task allocation, computing resource allocation and bandwidth allocation. The simulation results show that compared with other schemes, the proposed dynamic scheme can effectively reduce the energy consumption, network backlog sum and average queue delay of UAV network. Secondly, under different learning rate combinations, the reward of TD3PG algorithm is increased by 13.6%, 24% and 20.4% and 17.9%, respectively, compared with DDPG algorithm and DDQN algorithm.