Low-Carb: A practical scheme for improving energy efficiency in cellular networks

Electricity cost constitutes a significant fraction of the total operations costs in a cellular network. We present Low-Carb, a practical scheme which reduces the power consumption in such networks. Low-Carb achieves this by coupling Base Transceiver Station (BTS) power savings with Call hand-off-two features widely available to cellular operators. Motivated by the observation that most callers are in the vicinity of multiple BTSs, Low-Carb allows calls to hand-off from one BTS to another so that BTS power savings can be applied to a maximal number of BTSs throughout the cellular network. The resulting reduction in energy consumption is shown to be governed by an optimization problem. We also provide optimal and heuristic solutions to this problem. We use BTS locations and traffic volume data from a large live GSM network to evaluate the power savings possible using our proposed approach. Our results indicate that performing coordinated call hand-off and BTS power-savings, a GSM 1800 network operator with about 7000 sites nation-wide can reduce annual electricity consumption by up to 35.36 MWh. This is at least 9.8% better than the energy savings achievable by using BTS power savings alone.