Throughput-Outage Analysis and Evaluation of Cache-Aided D2D Networks With Measured Popularity Distributions
Throughput-Outage Analysis and Evaluation of Cache-Aided D2D Networks With Measured Popularity Distributions
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DOI：
10.1109/twc.2019.2935452
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发表时间：
2019-11-01
影响因子：
10.4
通讯作者：
Sastry, Nishanth
中科院分区：
文献类型：
--
作者：
Lee, Ming-Chun;Ji, Mingyue;Sastry, Nishanth
在用户设备上缓存视频文件，结合通过设备到设备 (D2D) 通信进行文件交换，是提高无线网络吞吐量的一种有前景的方法。先前的理论研究表明，吞吐量可以增加几个数量级，但假设采用 Zipf 分布来对流行度分布进行建模，该分布基于有线网络中的观察。因此，缓存辅助 D2D 视频分发是否能够在实践中提供现有理论文献所承诺的好处的问题仍然悬而未决。为了回答这个问题，我们专门针对移动用户视频请求的流行度分布提供了新结果。基于广泛的现实世界数据集，我们采用广义分布，称为 Mandelbrot-Zipf (MZipf) 分布。我们首先证明这种流行度分布可以很好地拟合实际数据。使用该分布，我们分析了缓存辅助 D2D 网络的吞吐量与中断权衡，并表明当 MZipf 分布充分倾斜时，缩放定律与 Zipf 流行度分布的情况相同，这意味着文献中先前承诺的好处确实可以在实践中实现。为了支持该理论，提供了使用数值实验的实际评估，并表明缓存辅助的 D2D 可以优于来自基站的传统单播。
Caching of video files on user devices, combined with file exchange through device-to-device (D2D) communications is a promising method for increasing the throughput of wireless networks. Previous theoretical investigations showed that throughput can be increased by orders of magnitude, but assumed a Zipf distribution for modeling the popularity distribution, which was based on observations in wired networks. Thus the question whether cache-aided D2D video distribution can provide in practice the benefits promised by existing theoretical literature remains open. To answer this question, we provide new results specifically for popularity distributions of video requests of mobile users. Based on an extensive real-world dataset, we adopt a generalized distribution, known as Mandelbrot-Zipf (MZipf) distribution. We first show that this popularity distribution can fit the practical data well. Using this distribution, we analyze the throughput-outage tradeoff of the cache-aided D2D network and show that the scaling law is identical to the case of Zipf popularity distribution when the MZipf distribution is sufficiently skewed, implying that the benefits previously promised in the literature could indeed be realized in practice. To support the theory, practical evaluations using numerical experiments are provided, and show that the cache-aided D2D can outperform the conventional unicasting from base stations.