The emerging low earth orbit (LEO) broadband constellations are capable of distributing videos via advanced multicasting techniques to multiplex bandwidth in both satellite access and backbone networks, thereby reducing huge amounts of traffics. Previous work on LEO-based multicast routing relied on IP multicast, which fails to employ global information to achieve the optimal bandwidth saving. In this article, we leverage the novel software-defined multicasting paradigm on LEO constellations to empower advanced video distribution with optimized multicast trees, thereby significantly outperforming conventional multicasting techniques. In the presence of quality-of-service (QoS) constraints, we propose weighted rectilinear Steiner minimal trees (WRSTs), which balance bandwidth saving and QoS requirements. Our multicast tree algorithm adopts the Voronoi diagram and Delaunay triangulation to obtain suitable candidate Steiner points, which are exploited by subsequent iterative edge substitutions for WRST construction. We also design QoS-aware multicast management schemes to deal with frequent member updates and potential failures in LEO constellations. We carry out thorough experiments to demonstrate the effectiveness and efficiency of the proposed routing tree construction algorithm and multicasting protocols when compared with traditional algorithms.

中文翻译：

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LEO 卫星网络中的 QoS 感知软件定义组播


新兴的低地球轨道 (LEO) 宽带星座能够通过先进的组播技术分发视频，以复用卫星接入和骨干网络中的带宽，从而减少大量流量。以前基于LEO的组播路由工作依赖于IP组播，无法利用全局信息来实现最佳的带宽节省。在本文中，我们利用 LEO 星座上新颖的软件定义多播范例，通过优化的多播树实现高级视频分发，从而显着优于传统的多播技术。在存在服务质量 (QoS) 约束的情况下，我们提出加权直线 Steiner 最小树 (WRST)，它可以平衡带宽节省和 QoS 要求。我们的多播树算法采用 Voronoi 图和 Delaunay 三角剖分来获得合适的候选 Steiner 点，并通过后续迭代边缘替换来构建 WRST。我们还设计了 QoS 感知的多播管理方案来处理 LEO 星座中的频繁成员更新和潜在故障。我们进行了彻底的实验，以证明所提出的路由树构建算法和多播协议与传统算法相比的有效性和效率。