Cache Strategy Design Based on Clustered D2D Cache Network

Mobile edge caching can deliver contents directly without the backhaul link, which can effectively solve the problem of spectrum scarcity caused by huge mobile data traffic. The cooperative cache strategy is able to make full use of user equipments with limited cache capacity to improve the network hit rate and cache diversity. First, this paper proposes a clustering algorithm based on the content providers, which is different from the existing clustering algorithms. The cache capacity in the cluster formed by this algorithm is collectively used to provide higher content hit probability and diversity. We further consider the impact of social interest on the performance of caching strategies. On the basis of random geometry theory, we derive the closed-form expressions of the hit rate of intra-cluster cache, inter-cluster cache and base station cache respectively. Finally, we obtain the closed-form expression of the network hit rate of the entire cluster cache, and investigate the problem of maximizing the network hit rate from the content caching strategy. Through the simulation of the key indicators, the results show that the proposed caching strategy is better than other cooperative caching strategies in data offloading performance.