Wireless Evolution Towards 5G And Beyond

摘要

Mobile communications network has now evolved into the 4th generation (4G). An increasing popularity of broadband services demands a significant improvement in the spectrum efficiency and energy efficiency. Promising approach is to enhance the radio access network by using MIMO technology. After briefly overviewing the evolution of mobile communications network, we will overview the recent advances in distributed MIMO RAN. A number of distributed antennas are deployed over a traditional macro-cell area covered by a macro-cell base station (MBS). They are connected to the MBS by the optical mobile fronthaul. Distributed MIMO RAN exploits the spatial distribution of both antennas and users. Some of distributed antennas near a user terminal are selected to perform distributed MIMO cooperative transmission. A new frequency band, e.g. the mm wave band, where abundant bandwidth remains unused, will be utilized. Therefore, there exists high Doppler shift, which cases the channel estimation problem. Furthermore, adjacent macro-cells are loosely connected, and hence, the inter-cell interference (ICI) problem will be produced. In this talk, we will present adaptive channel estimation and adaptive ICI coordination (ICIC). Finally, we will discuss about RAN evolution into beyond 5G.