Transmitting, Fast and Slow: Scheduling Satellite Traffic through Space and Time
Transmitting, Fast and Slow: Scheduling Satellite Traffic through Space and Time
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DOI：
10.1145/3570361.3592521
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发表时间：
2023-10
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影响因子：
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通讯作者：
Bill Tao;Maleeha Masood;Indranil Gupta;Deepak Vasisht
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作者：
Bill Tao;Maleeha Masood;Indranil Gupta;Deepak Vasisht
地球观测低地球轨道（LEO）卫星收集了大量的数据，这些数据需要首先传输到地面站，然后传输到云端进行存储和处理。如今，Satellite将数据传输到地面站，在每个接触期间充分利用带宽。我们表明，由于地面站的布局和轨道特性，这种方法会使一些地面站过载，而另一些地面站过载，导致吞吐量损失和图像的端到端延迟。我们提出了一个新的端到端调度系统，称为Umbra，它计划从大型卫星星座通过地面站到云的传输，通过考虑空间和时间因素，即，轨道动力学、带宽限制和队列大小。Umbra的核心是一类新的调度算法，称为保留调度，其中发送方（即，卫星）选择性地欠利用到地面站的一些链路。我们发现，Umbra的反直觉方法将吞吐量提高了13- 31%，并将P90延迟降低了3- 6倍。
Earth observation Low Earth Orbit (LEO) satellites collect enormous amounts of data that needs to be transferred first to ground stations and then to the cloud, for storage and processing. Satellites today transmit data greedily to ground stations, with full utilization of bandwidth during each contact period. We show that due to the layout of ground stations and orbital characteristics, this approach overloads some ground stations and underloads others, leading to lost throughput and large end-to-end latency for images. We present a new end-to-end scheduler system called Umbra, which plans transfers from large satellite constellations through ground stations to the cloud, by accounting for both spatial and temporal factors, i.e., orbital dynamics, bandwidth constraints, and queue sizes. At the heart of Umbra is a new class of scheduling algorithms called withhold scheduling, wherein the sender (i.e., satellite) selectively under-utilizes some links to ground stations. We show that Umbra's counter-intuitive approach increases throughput by 13--31% & reduces P90 latency by 3--6 ×.