Fundamentals of 5G Mobile Networks, First Edition. Edited by Jonathan Rodriguez. © 2015 John Wiley & Sons, Ltd. Published 2015 by John Wiley & Sons, Ltd. 1.1 Introduction We have been witnessing an exponential growth in the amount of traffic carried through mobile networks. According to the Cisco visual networking index [1], mobile data traffic has doubled during 2010–2011; extrapolating this trend for the rest of the decade shows that global mobile traffic will increase 1000x from 2010 to 2020. The surge in mobile traffic is primarily driven by the proliferation of mobile devices and the accelerated adoption of data‐hungry mobile devices – especially smart phones. Table 1.1 provides a list of these devices along with their relative data consumptions. In addition to the increasing adoption rate of these high‐end mobile devices, the other important factor associated with the tremendous mobile traffic growth is the increasing demand for advanced multi‐media applications such as Ultra‐High Definition (UHD) and 3D video as well as augmented reality and immersive experience. Today, mobile video accounts for more than 50% of global mobile data traffic, which is anticipated to rise to two‐thirds by 2018 [1]. Finally, social networking has become important for mobile users, introducing new consumption behaviour and a considerable amount of mobile data traffic. The growth rate of mobile data traffic is much higher than the voice counterpart. Global mobile voice traffic was overtaken by mobile data traffic in 2009, and it is forecast that Voice over IP (VoIP) traffic will represent only 0.4% of all mobile data traffic by 2015. In 2013, the number of mobile subscriptions reached 6.8 billion, corresponding to a global Drivers for 5G: The ‘Pervasive Connected World’ Firooz B. Saghezchi, 1 Jonathan Rodriguez, 1 Shahid Mumtaz, 1 Ayman Radwan, 1 William C. Y. Lee, 2 Bo Ai, 3 Mohammad Tauhidul Islam, 4 Selim Akl 4 and Abd‐Elhamid M. Taha 5 1 Instituto de Telecomunicações, Aveiro, Portugal 2 School of Advanced Communications, Peking University, China 3 State Key Laboratory of Rail Traffic Control and Safety, Beijing, China 4 School of Computing, Queen’s University, Kingston, Ontario, Canada 5 College of Engineering, Alfaisal University, Riyadh, KSA 1 COPYRIGHTED MATERIAL