Bandwidth Slicing for Socially-Aware D2D Caching in SDN-Enabled Networks

The explosive growth of mobile data traffic poses challenge to the network architecture design. Caching popular contents on device level instead of infrastructure level, termed as distributed caching, can potentially alleviate the traffic load. As an emerging technology to decouple the control plane from the physical network topology, software-defined networking (SDN) promises to build a flexible, scalable, and programmable framework by enabling centralized network control and management. In this paper, assuming that user can leverage social networking and share contents via device-to-device (D2D) communications, we propose a SDN-enabled socially aware D2D caching scheme, in which Internet service providers split bandwidth into distinct slices and dynamically allocate these slices to content providers (CPs) for controlling traffic flows. Then, the CPs can provide share contents with content requesters for further traffic offloading. To improve the spectrum efficiency, we conceive this caching scheme with the architecture of hierarchical matching game. In this way, the combinatorial problem can be solved in two-stage. In the first stage, we propose a dynamic bandwidth allocation algorithm to allocate distinct bandwidth slices for differentiated quality-of-service requirements. In the second stage, we formulate the content sharing problem as a many-to-many matching game with externalities. To solve this complex matching problem, we design a novel distributed algorithm with faster converge speed. A joint solution is thus provided to solve the content sharing and power allocation problems iteratively by exploiting non-orthogonal multiple access. We conduct extensive simulations to demonstrate that our proposed schemes provide a better tradeoff between performance and complexity than other benchmarks.