1. Cisco visual networking index: Global mobile data traffic forecast update, 2015 ? 2020,2016
2. Next generation 5G wireless networks: A comprehensive survey;Agiwal;IEEE Commun. Surv. Tutor.,2016
3. What will 5G be?;Andrews;IEEE J. Sel. Areas Commun.,2014
4. Ultra-dense networks: Survey of state of the art and future directions;Yu,2016
5. Ultra-dense networks: A survey;Kamel;IEEE Commun. Surv. Tutor.,2016