Research On 5G Network Hierarchical Caching Mechanism

In recent years,with the explosive growth of mobile network traffic,the existing mobile network architecture faces unprecedented challenges in terms of network capacity,delay guarantee,security and reliability.In the upcoming fifth-generation(5G)cellular network,some new technologies such as large-scale multiple input multiple output(Massive.-MIMO),millimeter wave band,cloud wireless access network(C-RAN),Software Defined Network(SDN)and Network Function Virtualization(NFV)will be used and deployed.In the fifth generation(5G)cellular networks,caching and network function virtualization have been considered as promising techniques.In virtualized 5G cellular networks,the caching resource deployed by the infrastructure providers(InPs)can be abstracted into isolated slices and transparently shared by mobile virtual network operators(MVNOs).In this case,how the MVNOs to share the caching resource in virtualization of 5G cellular networks is one of the most important issues.In this paper,different from previous works,we consider a hierarchical caching architecture that radio access network(RAN)and core network have the caching capability with virtualization.Then,the problem of hierarchical caching resource sharing for MVNOs is studied,which is formulated as a competitive game to maximize their expected revenue based on the oligopoly market model.Due to finding the optimal solution is a hard problem in the hierarchical caching resource allocation problem,we decompose the optimization problem into two independent sub problems in RAN and core network,respectively.For the sub problem in RAN,we first prove that the utility function is a strict concave function with a unique maximum value,then the Newton-Raphson iteration method is used to obtain the optimal solution.For the sub problem in CN,we propose a request probability sorting algorithm to obtain the hit rate of CN node,which is used to get the optimal solution of the problem.Finally,the performance of the scheme is verified by simulation and compared with the conclusions in the derivation process,which is consistent with the conclusions in the derivation process.