Decentralized Coded Caching Attains Order-Optimal Memory-Rate Tradeoff
Decentralized Coded Caching Attains Order-Optimal Memory-Rate Tradeoff
复制标题
DOI：
10.1109/tnet.2014.2317316
复制
发表时间：
2015-08-01
影响因子：
3.7
通讯作者：
Niesen, Urs
中科院分区：
文献类型：
--
作者：
Maddah-Ali, Mohammad Ali;Niesen, Urs
在网络中分布式的存储器中复制或缓存热门内容是一种减少网络峰值负载的技术。传统上，人们认为这种缓存的主要性能提升源于使部分所请求的数据更接近终端用户。然而，我们最近表明，通过利用缓存来创造编码多播机会，即使对于有不同需求的用户，通过跨数据流编码，也能实现更显著的提升。这些编码多播机会是由网络中各个缓存处精心设计的内容重叠所促成的，而这种重叠是由一个中央协调服务器创建的。在许多场景中，可能没有这样的中央协调服务器，这就引出了一个问题：在更分散的环境中是否仍然能够实现这种多播增益。在本文中，我们提出了一种高效的缓存方案，其中内容放置是以分散的方式进行的。换句话说，内容放置不需要协调。尽管缺乏协调，但所提出的方案仍然能够创造编码多播机会，并实现接近最优集中式方案的速率。
Replicating or caching popular content in memories distributed across the network is a technique to reduce peak network loads. Conventionally, the main performance gain of this caching was thought to result from making part of the requested data available closer to end-users. Instead, we recently showed that a much more significant gain can be achieved by using caches to create coded-multicasting opportunities, even for users with different demands, through coding across data streams. These coded-multicasting opportunities are enabled by careful content overlap at the various caches in the network, created by a central coordinating server. In many scenarios, such a central coordinating server may not be available, raising the question if this multicasting gain can still be achieved in a more decentralized setting. In this paper, we propose an efficient caching scheme, in which the content placement is performed in a decentralized manner. In other words, no coordination is required for the content placement. Despite this lack of coordination, the proposed scheme is nevertheless able to create coded-multicasting opportunities and achieves a rate close to the optimal centralized scheme.