gy from the domain being described in the book, with appropriate definitions and explanations in each chapter. Market Drivers Reza Arefi1 and Sasha Sirotkin 1 Intel Corporation, USA 2Intel Corporation, Israel 2.1 Introduction In this chapter we discuss various technological, regulatory, and market drivers that trig- gered the development of 5G and the problems 5G is expected to solve. We then attempt to derive how these affect the Radio Access Network (RAN) architecture and its evolution in order to support 5G, which is the primary focus of the book. This is not an easy task, as there is no universally agreed definition of what constitutes 5G. To some, this is the technology that meets the International Telecommunications Union (ITU) IMT-20201 requirements and therefore will be able to make use of the newly identi- fied spectrum for IMT. To others, this is an expansion of cellular technologies beyond their traditional mobile broadband (MBB) use cases and markets into Internet of Things (IoT), private networks (i.e. networks deployed by entities other than traditional cellular opera- tors), and other markets where cellular technologies have not been commonly used before. Some others view 5G as simply an evolution of 4G (Long-Term Evolution [LTE] to support higher throughputs, lower latencies, and better energy efficiency targeting primarily MBB; that is, the same use cases as 4G. Some point out that the primary technological advance- ment of 5G is the support of mm Wave spectrum, while others believe that 5G is the turning point when cellular networks finally fully embrace virtualization (including RAN), driving down operational costs by opening up RAN to bigger competition. Given such diverse views in the industry it is hard to pinpoint a single major market driver for 5G. Moreover, it is quite clear at the time of writing this book that, while at least some of the driving forces mentioned above (e.g. mmWave) do provide substantial technological improvements, these do not necessarily address an existing market ne