Energy cost reduction in cellular networks through dynamic base station activation

In this paper, we investigate dynamic base station activation with the aim of reducing energy consumption in cellular networks. Using the two-timescale Lyapunov optimization approach, we develop an online control algorithm to choose active set of base stations so as to satisfy users´ demands while incurring minimum energy consumption. The algorithm selects the minimum cardinality subset of base stations that ensures stabilization of user queues. Our algorithm achieves stabilization without relying on instantaneous feedback about the network conditions, instead it only requires information about the average load and demand over a coarse time scale. The formulated problem which consists of joint base station activation and user association is generally intractable. However, we show that it features submodularity, and consequently present a near-optimal solution for certain instances of the problem. We further develop a greedy algorithm to solve general cases of the problem. We supplement our theoretical analysis with numerical results to demonstrate the behavior of our algorithm in terms of energy and delay in some example network scenarios.