The File Chunk Cache Strategy for D2D Cluster Based on Mobile Helpers

In order to optimize the D2D cache hit ratio, the mobile helper equipments (HEs) cache is added to the cluster users. At the same time, a popular file chunk batch cache strategy (FCPhit) based on the helper equipment is proposed. Firstly, users with similar file requests are clustered into one cluster. Then, the users are batched and the popular file is divided into several chunks. The user equipment caches the first chunk of the file and HEs cache the other file chunks. Finally, the strategy is compared with the most popular existing caching strategy (MPhit), the optimal caching strategy (OCPhit), and the equal probability random cache strategy (EPRC). The results show that the present strategy can effectively improve the cache hit ratio of the system.