Performance And Cache Optimization In Heterogeneous Network For Content Service

The rapid proliferation of smart mobile devices and mobile applications brings about massive demand of mobile data traffic,which leads to the solution of heterogeneous radio access network to increase system capacity and meet growing demand of traffic by deploying a large number of small base stations.Mobile video is the most important component of traffic load in heterogeneous radio access network.Since most content-oriented traffic originates from repeated downloads of a few popular mobile videos,caching popular contents in HetNet is an effective way to handle huge traffic.This thesis focuses on content cache cooperative optimization in heterogeneous radio access network.Firstly,a software-defined cache-enabled cooperative controller framework(SDCCF)is proposed to optimize performance of content service in heterogeneous radio access network based on the concept of software-defined networking(SDN).The proposed SDCCF supports cluster-based cooperative control between controllers,cooperative content caching among cache-enabled entities as well as objective-centric cooperative optimization for content caching.Secondly,based on SDCCF,the joint optimization of content caching and sleep mechanism for energy-harvesting in HetNet is studied,a dynamic energy-harvesting based caching algorithm with sleep-active scheduling is proposed.The simulation results show that the proposed algorithm has better performance on energy consumption compared with other caching algorithms without joint optimization of energy-harvesting and sleep mechanism.Thirdly,based on SDCCF,cluster-based cooperative optimization for content caching is investigated,and a cluster-based cooperative caching algorithm is proposed.The performance evaluation results reveal that the proposed algorithm has superior performance on cache hit ratio to another three algorithms without clustering and cooperative caching.