Minimizing traffic cost of content distribution and storage allocation in cloud radio access networks

Abstract

In Cloud Radio Access Networks (C-RANs), remote radio heads (RRHs) and baseband units (BBUs) are deployed for storing contents to alleviate the bottleneck of the data cloud, shorten the delay of content request, and reduce the cost of network service. In this paper, we advocate the issue of content distribution in C-RANs to meet the ever-increasing contents of 5G cellular networks. Our goal is to minimize the total traffic cost of content transmission by jointly distributing content and allocating storage in RRHs and BBUs of C-RANs. The problem is formulated as a mix-integer linear programming (MIP). Then, an algorithm with a bounded approximation ratio is proposed to obtain the feasible solution of the MIP. The simulation results validate that the proposed algorithm outperforms two very recent heuristic algorithms in the metric of traffic cost. They also demonstrate that the difference between the solution obtained by the algorithm and the optimal solution of the MIP is very small. In addition, the experimental results show that the proposed algorithm is feasible in C-RANs. Further, another algorithm is proposed for exchanging contents between neighbor RRHs in content provision.