面向软件定义无线接入网的高效协作内容缓存算法

为了缓解海量的移动业务数据与容量受限的无线接入网回传链路之间的矛盾，本文提出一种面向软件定义无线接入网（SD-RAN）的协作内容缓存网络架构.在宏蜂窝基站（MBS）的控制管理下，小蜂窝基站（SBS）可以在存储单元有序存储一些高流行度的内容.针对SBS存储单元空间受限问题，进一步提出SD-RAN网络架构下的协作内容缓存算法.该算法中，每个SBS缓存空间被分割成两部分：（1）用于存储全网流行度最高的公共内容以保证各小蜂窝小区本地命中率.（2）用于存储流行度较高的差异化的内容以促进MBS内SBS之间的协作.在此基础上，解析推导具有最优平均内容获取开销的分割参数闭合表达式.仿真结果表明该算法在不同系统参数条件下能显著降低SD-RAN的平均内容获取开销.

An Efficient Cooperative Content Caching Algorithm for Software-Defined Radio Access Networks

In order to alleviate the contradiction between the massive mobile data traffic and the limited capacity of wireless backhaul links,a cooperative content caching algorithm is proposed for Software-Defined Radio Access Networks (SD-RAN),where the Macro-cell Base Station (MBS) equipped with centralized control logic and programmable interfaces,coordinates the content caching performed at the Small-cell Base Stations (SBSs).Moreover,in order to strike a balance between the local hit ratio and miss ratio,a cooperative caching algorithm is proposed by dividing the cache space of each SBS into two portions,one for storing the most popular contents that are the same across SBSs,one for storing unique contents to facilitate inter-SBSs cooperation.The optimal partition factor at which the average content provisioning cost of the SD-RAN is minimized is analytically obtained in a closed form.