Collaborative EPC and RAN Caching Algorithms for LTE Mobile Networks

The explosive growth of online videos brings a great pressure on LTE mobile networks caused by huge mobile data traffics. Deploying caches at the evolved packet core (EPC) and radio access network (RAN) in LTE mobile networks can efficiently relieve this pressure by the way of reducing duplicate content transmissions. In this paper, we propose collaborative caching algorithms for the LTE mobile network with caches deployed at the EPC and RAN to reduce the bandwidth cost of Internet access and improve the end-user experience. We decompose the caching problem into a content placement subproblem and a request routing subproblem. We solve the content placement subproblem with a greedy placement algorithm by utilizing its matroid and submodular properties. As for the request routing subproblem, we solve it by transforming it into the problem of maximizing a submodular function subject to a matroid constraint and present a greedy algorithm. Both the proposed algorithms can achieve at least 1=2 of the optimal solution. Experiment results show that our proposed algorithms can significantly improve the performance in terms of access cost and supported request compared with three reference algorithms.