The Internet of Things (IoT), one of the hottest trends in technology, is transforming our future by interconnecting everything; humans, vehicles, appliances, utilities, infrastructures, street lights, etc., through intelligent connections. For deploying the realization of IoT by 2020, Fifth Generation (5G) wireless communication networks are considered as an essential unifying fabric that will connect billions of devices in some of the fastest, most reliable and most effi cient ways possible, whose impact will be revolutionary, reshaping industries and transforming our world. Therefore, 5G is currently attracting extensive research interest from both industry and academia. It is widely agreed that in contrast to 4G, 5G should achieve 1000 times system throughput, 10 times spectral effi ciency, higher data rates (i.e., the peak data rate of 20 Gb/s and the user experienced rate of 1Gb/s), 25 times average cell throughput, less than 1 ms in end-to-end (E2E) latency, and 100 times higher connectivity density. Among those requirements, the 1000-fold increase in system capacity becomes the most important and maybe the most challenging for 5G systems.