关键词: 移动内容分发网络, 缓存管理, 子模函数, 协作缓存

Abstract: With the development of mobile Internet and the increase of the number of users, dynamic caching mechanism is widely used in audio & video services to reduce the data traffic going through backhaul backbone links and improve the viewing experience. How to adjust the cache content of multiple nodes according to the network and user demand to cut down the traffic in backbone links is an important problem to be solved in current cache deployment. Based on the submodular function theory, the proactive and reactive resource allocation adjustment schemes and their algorithms are proposed. According to the popularity of the content, the proactive scheme puts the video files to the cache space to minimize overhead of obtaining them. The reactive one adjusts the content in the space of the node in time to cater to the popularity’s change, so as to improve the utilization of the cache resources and user experience, and reduce the rate of occupied bandwidth in the backbone links. The complexity of the minimum access cost algorithm is related to the size of the cache space, which can quickly iterate out the resource allocation scheme when the cache space is tight. Numerical simulation shows that the proactive and reactive resource allocation schemes can effectively alleviate the traffic load of the remote server and improve the user’s experience.

Key words: mobile content delivery networks, management of caching, submodular functions, cooperative caching