Radio Resource Management in Multi-Tier Cellular Wireless Networks

CHAPTER 1

OVERVIEW OF MULTI-TIER CELLULAR WIRELESS NETWORKS

1.1 INTRODUCTION

The demand of wireless services (e.g., data, voice, multimedia, e-Health, online gaming, etc.) through the cellular networks is ever-increasing. A recent statistics in [1] shows that, in March 2009, there were approximately 4.8 billion of mobile subscribers all over the world and this number is expected to reach 5.9 billion by 2013. The Global Mobile Data Traffic Forecast Report presented by Cisco predicts 2.4 exabytes (1 exabyte = 1018 bytes) mobile data traffic per month for the year 2013 [2]. It has been indicated in [3] that the global mobile data traffic has tripled each year since 2008 which is projected to increase up to 26-fold between 2010 and 2015. This results up to 6.9 exabytes of mobile data traffic per month for the year 2015 [2].

Satisfying the posed capacity demand has become very challenging, and the challenge has been even more acute with the introduction of the machine-to-machine (M2M) communications and the Internet of Things (IoT). With the introduction of M2M, the network usage goes beyond the conventional voice and data usage and needs innovative solutions to handle the growing amount of traffic and user population. It is expected that by 2020 there will be more than 50 billion connected devices, which is almost 10 times the number of currently existing connected devices [4]. Note that at least 60% of the Internet traffic will be transferred via wireless access [5].

Figure 1.1