Throughput and Delay Scaling of Content-Centric Ad Hoc and Heterogeneous Wireless Networks
Throughput and Delay Scaling of Content-Centric Ad Hoc and Heterogeneous Wireless Networks
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DOI：
10.1109/tnet.2017.2718021
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发表时间：
2015-04
期刊：
影响因子：
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通讯作者：
M. Mahdian;E. Yeh
中科院分区：
文献类型：
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作者：
M. Mahdian;E. Yeh
我们研究了无线缓存网络的吞吐量和延迟特性，其中用户主要对检索存储在网络中的内容感兴趣，而不是维护源-目的通信。假设节点在网络区域内均匀分布。每个节点都有一个容量有限的内容存储，用于缓存内容。我们提出了一个可实现的缓存和传输方案，请求者从欧几里得距离中最近的缓存点检索内容。我们建立了可实现方案的吞吐量和延迟缩放，并证明了在一类方案中吞吐量和延迟性能是有序最优的。然后我们解决缓存优化问题，并评估Zipf内容流行度分布的网络性能，让内容类型的数量和网络大小都趋于无穷大。最后，我们将分析扩展到异构无线网络，其中除了无线节点外，网络区域中还有许多均匀随机分布的基站。我们表明，为了在顺序意义上实现异构网络中更好的性能，基站的数量需要大于节点数量与内容类型数量的比率。此外，我们表明，如果Zipf内容流行度分布指数超过3/2，异构网络在顺序意义上不会产生性能优势。
We study the throughput and delay characteristics of wireless caching networks, where users are mainly interested in retrieving content stored in the network, rather than in maintaining source–destination communication. Nodes are assumed to be uniformly distributed in the network area. Each node has a limited-capacity content store, which it uses to cache contents. We propose an achievable caching and transmission scheme whereby requesters retrieve content from the caching point, which is closest in the Euclidean distance. We establish the throughput and delay scaling of the achievable scheme, and show that the throughput and delay performance are order-optimal within a class of schemes. We then solve the caching optimization problem, and evaluate the network performance for a Zipf content popularity distribution, letting the number of content types and the network size both go to infinity. Finally, we extend our analysis to heterogeneous wireless networks where, in addition to wireless nodes, there are a number of base stations uniformly distributed at random in the network area. We show that in order to achieve a better performance in a heterogeneous network in the order sense, the number of base stations needs to be greater than the ratio of the number of nodes to the number of content types. Furthermore, we show that the heterogeneous network does not yield performance advantages in the order sense if the Zipf content popularity distribution exponent exceeds 3/2.