How to make key 5G wireless technologies environmental friendly: A review

Energy efficiency in cellular networks has increasingly become important to the cellular network operators due to its significant economic and ecological influence in the forthcoming generation of wireless networks, ie, the fifth-generation (5G) network. To pursue a vision of green communication, this study presents a comprehensive overview and discusses how the key physical layer techniques that will be adopted in the 5G technology can improve energy efficiency to achieve a sustainable wireless network. Among the key 5G technologies discussed are massive multiple-input multiple-output, green heterogeneous networks, green millimeter wave, green 5G device-to-device communication, green machine-to-machine communication, and energy-efficient 5G architecture. The review concludes that the 5G technology will soon fulfill the critical requirements of low-energy network while maintaining services with high performance. Potential research opportunities related to green 5G are also highlighted at the end of the article.