Energy-efficient design for latency-tolerant content delivery networks

In this paper, we investigate the energy efficiency performance of content delivery networks in which a data center serves multiple users via a shared wireless medium. Focusing on latency-tolerant applications, we propose energy-efficient precoding design and optimization that minimize the total energy consumption while guaranteeing some given quality of service constraints. In particular, an energy-buffering time trade-off (EBT) is derived in a closed-form expression for single-user scenarios, which reveals the impact of the key system parameters on the total energy consumption. We then formulate an energy minimization problem with a minimum mean square error (MMSE)-based precoding design for multiple-user scenarios. In order to overcome the non-convexity of the formulated problem, we propose an iterative algorithm which solves the problem suboptimally via a linear approximation of the non-convex constraint. Finally, numerical results are presented to demonstrate the effectiveness of the proposed solution.