Preference-Aware Caching Based on Cooperative Game for D2D Communication Networks

In cache enabled D2D communication networks, the cache space in a mobile terminal is relatively small compared with the huge amounts of multimedia contents. As such, how to cache the diverse contents in the multiple cache enabled mobile users, namely, the caching deployment, has substantial impact on network performance. In this paper, we propose a preference-aware caching based on cooperative game to incentivize users to cache contents for others, and then maximize the total cache utility by allocating cache space. We formulate a preference-aware cooperative game for cache utility maximization problem, which considers the user preference, physical distance, cache placement cost and cache space allocation. We divide the game into caching decision sub-game and cache space allocation sub-game. In caching decision sub-game, we obtain the Nash equilibrium solution by a heuristic caching decision method to minimize the total cost of getting objective contents. In cache space allocation sub-game, we solve the cache space allocation problem by using Lagrange method to finally maximize the total cache utility of the whole network. The convergence of the proposed algorithm is validated by simulation results. Compared with the existing caching schemes, the proposed scheme can achieve significant improvement on cache utility, cache hit ratio and content access delay gains.