Special Interest Group Cognitive Radio in 5 G White

Historically, mm-wave (mmW) communications have been used for point-to-point (P-P) terrestrial and satellite links, and more recently for indoor short-distance communications. New network architectures consisting of interwoven networks will be needed to meet the requirements of 5G, particularly an ever increasing demand for high data rates. It is believed that mmW communications will contribute to 5G thanks to large contiguous and available frequency bands. But just where, how and how much? This chapter discusses the state-of-the-art of mmW communications in terms of spectrum availability, standardization advancements and shortcomings. Some application scenarios are detailed. The use of mmW communications introduces challenges at the physical, medium access and link layers, as well as on the network management level. At last, licensing regimes will call for new sharing rules, particularly in the context of an evolving business ecosystem. .