From LTE-Advanced to 5G: Mobile Access System in Progress

There is a surge in the amount of mobile data traffic due to the growing popularity of smartphones and tablets and the increasing use of diversified applications that use pictures and movie files. The amount of mobile data traffic is expected to continue increasing with the rise of the Internet of Things (IoT) era, due to a huge increase in the number of telecommunication devices and technological advancements for enhancing the resolution of video data. The current prevalent system is LTE-Advanced—the so-called fourth-generation (4G) mobile access system—while technology is already under development across the world for fifth-generation (5G) systems. 5G involves very advanced technological requirements as it aims to increase transmission capacity by a thousand-fold compared with the current LTE. One of the required technological developments is to increase cell density. This paper first explains the mobile access system technology developed to counter increasing data traffic, and then it describes the centralized base band unit supporting LTE-Advanced and indoor femtocell base stations, each developed by Fujitsu. It also discusses the technological trends for 5G mobile access systems, with descriptions of activities to realize such technology.