Research On Content Cache Strategy In Next Generation Mobile Networks

The developments of intelligent devices have brought rapid growth of mobile traffic to telecom operators.In order to cope with the pressure brought by the rapid growth of mobile network services,and further improve the response rate of content requests and the utilization rate of network resources,content caching technology has become a hot topic in future mobile network research.On the other hand,network function virtualization technology is easy to combine with other key technologies(e.g.,software defined network,cloud computing,etc.)because of its powerful functions and open technology ideas.Therefore,the diversified technology architectures based on network function virtualization technology are considered as an important direction of the future evolution of telecommunication networks.This paper focuses on the application of content caching technology in the network function virtualization environment,focusing on the role of content caching strategy in the resource allocation process of network function virtualization.Firstly,since most requests for network content from mobile terminals are responded by the data center,the network traffic congestion occurs near the data center.In view of this phenomenon,this paper designs a Dynamic Caching Strategy based on Markov Chain(DCS-MC)for virtualized resource allocation process of network functions.The goals of this caching strategy are to minimize the cost of network service deployment while guaranteeing the quality of network service.Based on this caching strategy,a Viterbi Optimal Path Algorithm based on Virtual Starting Point(VOPA-VSP)is designed to solve the path mapping problem of service function chain.The simulation results show that DCS-MC and VOPA-VSP can effectively reduce the cost of network service deployment,balance network load,and provide network services with minimum delay according to the content of user requests.Secondly,considering that the placement of the cache function will greatly affect the path mapping process of the service function chain and the traffic distribution in the network,this paper describes the placement of the video cache function as an integer linear programming problem,with the goal of minimizing the deployment cost of the video cache function.In addition,a Placement Strategy of Video Caching Function based on Content Delivery Networks(PSVCF-CDN)is proposed,which takes into account theresource status of the node server and its surrounding links as well as the potential cost due to the deployment of video caching function.The simulation results show that PSVCF-CDN not only guarantees high user access rate,but also reduces the deployment cost of video caching function.