Research On Content Caching Mechanisms Of Mobile Edge Networks

The development of mobile Internet makes video application flourish.Video traffic dominates the explosive growth of data traffic worldwide.With the growth of mobile data traffic,the traditional mobile Internet architecture based on cloud computing is difficult to meet the low latency demand of video applications,and the network bandwidth consumption increases rapidly.Therefore,the center of Mobile communication Network architecture has evolved from base station to information and content direction.Mobile Edge Network includes Mobile fronthaul Network?Mobile midhaul Network and Mobile backhaul Network.Caching mechanism is one of the key technologies of mobile edge network.The content caching mechanism can effectively reduce the delay of users' acquisition of content and reduce the consumption of network transmission bandwidth.In traditional content caching mechanisms such as LCE(Leave Copy Everywhere),the caching of packets occurs at each node of the return path,resulting in severe redundancy of the node cache content.The mobile edge network content caching mechanism will cache the user access content near the edge node of the user.By increasing the diversity of cached content,which can not only effectively reduce the user access delay and relieve the network bandwidth pressure,but also increase the security of user data.However,the existing mobile edge network content caching mechanism,such as collaborative content caching mechanism,still faces the problems of insufficient cache space and imperceptible user mobility.In order to solve the above problems,this paper proposes two kinds of MEN content caching mechanisms from two perspectives,and analyzes and evaluates the performance on this basis.In order to solve the content cache location and edge node cache space is insufficient,we Proposed the Age of Information and Popularity-based Caching(Ao IPC),Ao IPC utilizes the attribute of communication,computing and cache of the edge node,The communication capability,computing capability and cache capability of the edge node are taken as evaluation indexes to measure the importance of the node,so as to select the appropriate cache contents,when the cache space is insufficient,the age of information and popularity of the cache contents in the cache node are used as reference indicators to determine which contents is replaced.Simulation results show that compared with traditional LCE and Prob,Ao IPC can improve cache hit ratio of edge nodes by 12.3% and 10.8%,respectivelyIn order to solve the user mobility problem,we proposed a user mobility-aware and node centrality based caching mechanism,UMANCC.UMANCC utilizes edge nodes to calculate the node centrality,idle rate of cache and cell sojourn time of users.A mobile edge network controller collects aforementioned information of edge nodes,and ranks each node base on the calculated importance factor of nodes.The caching node is selected according to the ranking result.Simulation results show that: compared with traditional caching mechanisms such as LCE and Prob,UMANCC effectively reduces the average number of hop count of fetching contents by up to 15.9%;it improves hit ratio of cache at edge nodes by at least 13.7%,and it reduces traffic flowing into core networks by up to 32.1%.To sum up,this paper studied the mobile edge network content caching problem,we proposed the Ao IPC and UMANCC,respectively.Improve the contents of the mobile edge network caching system,such as cache hit ratio,the average user access delay,user access to content the average hop count and the number of average content source node to accept the request.the research results will provide technical foundation for mobile edge network applications.