Device-to-Device Coded-Caching With Distinct Cache Sizes
Device-to-Device Coded-Caching With Distinct Cache Sizes
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DOI：
10.1109/tcomm.2020.2970950
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发表时间：
2019-03
影响因子：
8.3
通讯作者：
A. M. Ibrahim;Ahmed A. Zewail;A. Yener
中科院分区：
文献类型：
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作者：
A. M. Ibrahim;Ahmed A. Zewail;A. Yener
本文考虑了一个缓存辅助设备到设备（D2D）系统，其中用户配备了不同大小的缓存存储器。在低流量时段，服务器将内容放在用户的缓存内存中，因为它知道用户在高峰时段请求的文件只能通过D2D传输来传递。通过联合设计无编码缓存布局和线性编码D2D传输，最小化了最坏情况下的D2D传输负载。接下来，提出了具有未编码位置的D2D交付负载的新下界，并用于明确表征具有未编码位置的几种感兴趣情况下的最小D2D交付负载（MD2DDL）。特别是，在描述了相同缓存大小的MD2DDL之后，可以看到，在具有不同缓存大小的用户的网络中，只要最小的缓存大小大于某个阈值，就可以实现相同的传递负载。MD2DDL还具有小缓存大小制度、大缓存大小制度和三用户情况的特点。提供了基于服务器的交付负载与D2D交付负载的比较。最后，讨论了缓存辅助D2D系统与编码分布式计算（CDC）系统之间的联系和数学相似性。
This paper considers a cache-aided device-to-device (D2D) system where the users are equipped with cache memories of different size. During low traffic hours, a server places content in the users’ cache memories, knowing that the files requested by the users during peak traffic hours will have to be delivered by D2D transmissions only. The worst-case D2D delivery load is minimized by jointly designing the uncoded cache placement and linear coded D2D delivery. Next, a novel lower bound on the D2D delivery load with uncoded placement is proposed and used in explicitly characterizing the minimum D2D delivery load (MD2DDL) with uncoded placement for several cases of interest. In particular, having characterized the MD2DDL for equal cache sizes, it is shown that the same delivery load can be achieved in the network with users of unequal cache sizes, provided that the smallest cache size is greater than a certain threshold. The MD2DDL is also characterized in the small cache size regime, the large cache size regime, and the three-user case. Comparisons of the server-based delivery load with the D2D delivery load are provided. Finally, connections and mathematical parallels between cache-aided D2D systems and coded distributed computing (CDC) systems are discussed.