Energy efficiency of heterogeneous networks in LTE-advanced

Traditionally mobile operators have met the surge in mobile data traffic and the growing number of rural subscribers by deploying more macro base stations. This increases overall energy consumption, operational costs and carbon footprint of cellular networks. In this paper we investigate solutions for reducing the number and size of active macro cells following traffic load conditions in both homogeneous and heterogeneous networks. Results are presented as overall energy reduction gains for homogeneous macro-only and micro-only networks and heterogeneous joint macro-relay and micro-relay networks, using long-term-evolution-advanced technology. Results show that reducing the number of active cells using sleep mode at base stations, in low to medium traffic load conditions, combined with the deployment of small cells offer energy gains in both homogeneous and heterogeneous networks, but the most significant gains are observed in heterogeneous networks.