Optimal Energy Tradeoff among Communication, Computation and Caching with QoI-Guarantee

Energy efficiency is a fundamental requirement of modern data communication systems, and its importance is reflected in much recent work on performance analysis of system energy consumption. However, most works have only focused on communication and computation costs, but do not account for caching costs. Given the increasing interest in cache networks, this is a serious limitation. In this paper, we consider the energy consumption trade-off between communication, computation, and caching (C3) under a Quality of Information (QoI) guarantee in a communication network. To attain this goal, we formulate an optimization problem to capture the C3 costs, which turns out to be a non-convex Mixed Integer Non-Linear Programming (MINLP) Problem. We then propose a variant of spatial branch and bound algorithm (V-SBB), that can achieve \epsilon -global optimal solution to the original MINLP. We show numerically that V-SBB is more stable and robust than other candidate MINLP solvers under different network scenarios. More importantly, we observe that the energy efficiency under our C3 optimization framework improves by as much as 88% compared to any C2 optimization between communication and computation or caching.