Optimal Resource Allocation for Content Delivery in D2D Communications

Future wireless networks face a great challenge in spectral resource management to meet an overwhelming demand for network capacity. In 5G systems, Device-to-Device (D2D) communications is a key technology to alleviate this "capacity crunch" while content consumption is the key usage mode. In this work, we devise a resource allocation problem for a cellular network that facilitates the delivery of requested contents to its users via either BS mode or D2D mode. By solving the formulated optimization problem, we investigate the interplay between D2D transmissions, cache characteristics, and mode selection preference. Our numerical results suggest that while enabling D2D operation improves delivery performance significantly, how much a network can deliver in D2D mode is determined by both the network density and cache capacity.