Multi-popularity Multi-threshold Grouped Caching for Device-to-Device Communication

Among the proliferation of device-to-device (D2D) based caching schemes, the most popular content (MPC) caching and the largest content diversity (LCD) caching have recently gained research attention. By jointly exploiting the merits of both MPC, LCD and grouped caching strategies, in this paper, we propose a new multi-popularity multi-threshold grouped caching scheme for D2D communication (MMGC-D2D). Specifically, we first devise an optimal device grouping scheme aiming to improve the regional user fairness of grouped caching. Then, to maximize the gain of cache space and to minimize the outage probability of cached packets, we discuss in details a novel MPC-LCD threshold-based grouped caching placement optimization problem and its analytical property, while taking into account the packet request diversity (PRD). Simulations results show that the proposed scheme exhibits notable gains over existing methods.