QoS Provisionings for Device-to-Device Content Delivery in Cellular Networks

Device-to-device (D2D) technique provides a feasible way for content delivery among proximal users without deploying additional infrastructures. For the realization of D2D content delivery, it is important to guarantee quality-of-service (QoS) for supporting real-time content transmissions. In this paper, we formulate the content delivery problem based on a flow model and investigate mechanisms providing delay QoS guarantee. The delay performance is analyzed for the content dissemination with the aid of D2D communication. Based on the analyses of parameters affecting the performance of content delivery, an optimal resource allocation scheme is proposed to achieve the best energy efficiency of content delivery in cellular networks with guaranteed delay constraints for hybrid content requests. Then effects of content caching on D2D content delivery is studied and a caching management scheme is proposed to avoid cache overflow of users with a certain probability and satisfy QoS requirements of content delivery. Simulation results are presented that verify the analyzed influencing factors on D2D content delivery and the proposed QoS-provisioning schemes.