Cache hit ratio maximization in device-to-device communications overlaying cellular networks

This paper investigates the content placement problem to maximize the cache hit ratio in device-to-device (D2D) communications overlaying cellular networks. We consider offloading contents by users themselves, D2D communications and multicast, and we analyze the relationship between these offloading methods and the cache hit ratio. Based on this relationship, we formulate the content placement optimization as a cache hit ratio maximization problem, and propose a heuristic algorithm to solve it. Numerical results demonstrate that the proposed scheme can outperform existing schemes in terms of the cache hit ratio.