Research On Cache Placement Of Small Cell And Macrocell

With the development of mobile Internet,in order to solve the challenges of rapid growth in mobile subscriber data,operators deploy a large number of Small Cell base stations in the Macrocell network.Scholars have been using distributed cache technology in station and Small Cell to solve the demand for popular content.Due to the limitations of Small Cell storage capacity and other factors,efficient caching scheme is difficult.Therefore,this thesis focuses on the problem of cache placement in Small Cell and Macrocell network.This thesis firstly studies the cache placement scheme based on maximum distance separable code and network coding.The maximum distance separable code encode k source packets for n packets,and any k encoding data packets in the n packets can reconstruct the original k source package.The scheme is based on maximum distance separable code,and the objective problem will be transformed into a convex optimization problem.Simulation results show that the cache scheme based on the maximum distance separable code has lower average transmission rate and better performance.This thesis further makes use of network encoding and allows two file encoding and decoding through the modular two addition.The thesis puts forward scheme based on network encoding in order to reduce the communication between base station and small base station and puts forward the algorithm to complete file placement problem.The experimental results show that the caching scheme based on network encoding reduces the communication.The traditional cache scheme is based on unicast transmission.The thesis takes into account that a multicast transmission can service demand of multiple users to same file in a service period.The thesis puts forward cache scheme based on multicast,analyzes the advantages of multicast caching schemes and designs greedy algorithm to determine the file placement.The simulation results show that the scheme based on multicast transmission has lower energy consumption than the scheme based on unicast transmission.