Cooperation in 5G HetNets: Advanced Spectrum Access and D2D Assisted Communications

The evolution of conventional wireless communication networks to 5G is driven by an explosive increase in the number of wireless mobile devices and services, as well as their demand for any time and everywhere connectivity, high data rates, low latency, high energy efficiency, and improved quality of service. To address these challenges, 5G relies on key technologies, such as full duplex, D2D communications, and network densification. In this article, a heterogeneous networking architecture is envisioned, where cells of different sizes and radio access technologies coexist. Specifically, collaboration for spectrum access is explored for both full-duplex and cognitive-based approaches, and cooperation among devices is discussed in the context of the state-ofthe- art D2D assisted communication paradigm. The presented cooperative framework is expected to advance the understandings of the critical technical issues toward dynamic spectrum management for 5G heterogeneous networks.