Resource Allocation for Content Delivery in Cache-Enabled OFDMA Small Cell Networks

Abstract

To deal with explosively growing demands for multimedia contents from mobile users, content caching in base stations has been considered as an effective solution to improve the network performance by, e.g., offloading network traffic and improving users' Quality of Service (QoS). Moreover, the proactive caching policy in a cache- enabled system needs to be optimized taking into account of content delivery by wireless transmissions. Thus, in this paper, we investigate and propose an efficient resource allocation scheme for min-rate guaranteed content delivery in the downlink multiuser cache-enabled orthogonal frequency division multiple access small cell networks (OFDMA-SCNs). Our aim is to maximize the weighted sum of data rates in an OFDMA-SCN based on the constraints of the caching method, users' QoS, subcarrier reuse and small base stations' transmit power. We employ the alternating direction multiplier method to decompose the formulated complex nonconvex optimization problem into a series of simpler subproblems for which optimal solutions can be easily obtained, and propose corresponding low-complexity methods to solve the subproblems and then the whole problem. Numerical results demonstrate the effectiveness of the proposed resource allocation scheme.