QoS-Based Resource Allocation for Next-Generation Spacecraft Networks
QoS-Based Resource Allocation for Next-Generation Spacecraft Networks
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DOI：
10.1109/rtss.2012.68
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发表时间：
2012-12
期刊：
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通讯作者：
Arvind Kandhalu;R. Rajkumar
中科院分区：
文献类型：
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作者：
Arvind Kandhalu;R. Rajkumar
目前的航天器系统通常具有整体结构，但下一代航天器正在考虑采用“分块”结构。分离式航天器系统是一组独立的模块，它们通过无线通信保持集群飞行编队，并实现通常由单片卫星执行的功能。设想的分阶段办法的好处包括提高反应能力、更大的灵活性、更强的稳健性以及来自不同来源的具有不同信任程度的多个特派团的共存。然而，从资源分配和管理的角度来看，分级架构引入了重大的新挑战。集群和集群内的模块的移动的性质意味着网络拓扑是高度时变的。具有多个任务的集群可能需要通过网络传输具有不同程度的QoS要求（如及时性和数据传输可靠性）的消息。联合国系统必须为这些特派团确定适当和及时的资源分配。在本文中，我们解决这些资源分配的挑战，通过引入一个抽象的动态图，并扩展基于QoS的资源分配模型（Q-RAM）操作这些动态图。我们开发了一种机制，将一个动态图分解成多个静态子图，使用这些静态子图中的每个子图的资源分配问题被划分成多个子问题。我们通过建立一个名为SatSim的仿真框架，可以处理各种卫星配置和移动模型，对我们的解决方案进行了实验评估。所提出的解决方案是实现时变网络中的资源分配问题的接近最优的解决方案，同时大大降低了时间复杂度。
Current spacecraft systems generally have monolithic structures, but a "fractionated" architecture is being considered for next generation spacecrafts. A fractionated spacecraft system is a cluster of independent modules that communicate wirelessly to maintain cluster flight formations and realize the functions usually performed by a monolithic satellite. The envisioned benefits of the fractionated approach include enhanced responsiveness, greater flexibility, robustness and co-existence of multiple missions from different sources with varying degree of trust. The fractionated architecture, however, introduces significant new challenges from the perspective of resource allocation and management. The mobile nature of the clusters and the modules within the cluster implies that the network topology is highly time-varying. A cluster with multiple missions can require messages to be transmitted across the network with varying degrees of QoS requirements such as timeliness and data delivery reliability. The system must determine the appropriate and timely resource allocation for these missions. In this paper, we address these resource allocation challenges by introducing an abstraction of dynamic graphs, and extending the QoS based Resource Allocation Model (Q-RAM) to operate on these dynamic graphs. We develop a mechanism to decompose a dynamic graph into multiple static sub-graphs using which the resource allocation problem is partitioned into multiple sub-problems within each of these static sub-graphs. We have experimentally evaluated our solution by building a simulation framework called SatSim, which can handle a variety of satellite configurations and mobility models. The proposed solution is shown to achieve a near-optimal solution for the resource allocation problem in time-varying networks, while reducing time complexity significantly.