Kotaro Shiizaki

Field Experiment of High-Capacity Technologies for 5G Ultra High-Density Distributed Antenna Systems

In fifth-generation mobile communication systems (5G), it is necessary to significantly increase system capacity compared with 4G in order to accommodate rapidly increasing mobile data traffic. Cell densification has been considered an effective way to increase system capacity. However, severe intercell interference degrades the system capacity due to the increase of the line-of-sight environment between the transmission point (TP) and user equipment (UE). We propose large-scale coordinated multi-user multiple-input multiple-output (LSC-MU-MIMO), which combines joint transmission from all the TPs connected to a centralized baseband unit and MU-MIMO. We have investigated the downlink performance of LSC-MU-MIMO via both computer simulation and field experiments and showed that LSC-MU-MIMO can significantly reduce severe inter-TP interference and improve the system capacity of high-density small cells. In this paper, we introduce our recent field experiment results where reception antennas of UEs are mounted on a vehicle driving at speeds of 5 km/h to 40 km/h. We also compare distributed TP deployment with localized TP deployment when fixing the total number of transmission antennas.