Small cell densification is one of the effective ideas addressing the demand for higher capacity in cellular networks. The major problem in such networks is the limited capacity of wireless backhaul links. Caching the popular files in the memories of small cell base stations (SBSs) is an effective solution to this problem. One of the main challenges in caching is choosing the files to be stored in the memory of SBSs, especially when some SBSs have overlapped coverage. In this article, we propose a new caching scheme by exploiting the concept of graph coloring. To this end, we model the network scenario by a graph. This graph is divided into four subgraphs, i.e., placement, access, SBS, and delivery graphs. Through some modifications to the SBS graph, we convert it to a graph that can be colored. Then, we propose a graph coloring-based scheme to cache the popular files. We also derive a lower-bound for the hit rate improvement of our scheme compared to the conventional scheme which caches the most popular files anywhere. We evaluate the performance of our proposed scheme through simulations. Our results show that by employing the proposed scheme in a typical network, the load on the backhaul links is reduced significantly in average compared to the conventional scheme and some previously proposed schemes.

中文翻译：

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使用图着色将内容放置在缓存网络中

小蜂窝小区致密化是解决蜂窝网络对更高容量需求的有效思想之一。这种网络中的主要问题是无线回程链路的容量有限。在小型蜂窝基站（SBS）的内存中缓存流行文件是解决此问题的有效方法。缓存的主要挑战之一是选择要存储在SBS内存中的文件，尤其是当某些SBS覆盖范围重叠时。在本文中，我们通过利用图形着色的概念提出了一种新的缓存方案。为此，我们通过图形对网络场景进行建模。该图分为四个子图，即放置图，访问图，SBS图和传递图。通过对SBS图进行一些修改，我们将其转换为可以着色的图。然后，我们提出了一种基于图形着色的方案来缓存流行文件。与传统方案相比，我们可以将方案的命中率提高到一个较低范围，而常规方案可以在任何地方缓存最受欢迎的文件。我们通过仿真评估了我们提出的方案的性能。我们的结果表明，通过在典型网络中采用所提出的方案，与传统方案和某些先前提出的方案相比，回程链路上的负载平均平均降低了。