Base Station ON-OFF Switching in 5G Wireless Networks: Approaches and Challenges

To achieve the expected 1000x data rates under the exponential growth of traffic demand, a large number of BSs or APs will be deployed in 5G wireless systems to support high data rate services and to provide seamless coverage. Although such BSs are expected to be small-scale with lower power, the aggregated energy consumption of all BSs would be remarkable, resulting in increased environmental and economic concerns. In existing cellular networks, turning off the underutilized BSs is an efficient approach to conserve energy while preserving the QoS of mobile users. However, in 5G systems with new physical layer techniques and highly heterogeneous network architecture, new challenges arise in the design of BS ON-OFF switching strategies. In this article, we begin with a discussion of the inherent technical challenges of BS ON-OFF switching. We then provide a comprehensive review of recent advances on switching mechanisms in different application scenarios. Finally, we present open research problems and conclude the article.