Optimal Content Caching Policy Considering Mode Selection and User Preference under Overlay D2D Communications

The rapid growth of user demand for mobile data traffic, especially video streaming, places a serious burden on base stations. Cache-enabled D2D communication has emerged as a promising paradigm to offload cellular traffic, in which contents are cached at user devices and then shared among neighbors via D2D communications. It is a key step to optimize the content caching policy in the cache-enabled D2D-assisted offloading. To maximize D2D offloading probability, we propose an optimal content caching policy to cache valuable contents by considering both the mode selection and user preference of neighbors. Then we use a dual simplex method to solve the maximum D2D offloading probability problem. Comparing with existing schemes, the simulation results prove the advantage of our proposed scheme in the improvement of D2D offloading performance.