Daisuke Kurita

Field Experiments on 5G Radio Access Using Multi-Point Transmission

This paper presents outdoor field experimental results to clarify the 4x4 MIMO throughput performance from applying multi-point transmission in the 15 GHz frequency band in the downlink of 5G cellular radio access system. The experimental results in large-cell scenario shows that up to 30 % throughput gain compared to non-multi-point transmission is achieved although the difference for the RSRP of two TPs is over 10 dB, so that the improvement for the antenna correlation is achievable and important aspect for the multi-point transmission in the 15 GHz frequency band as well as the improvement of the RSRP. Furthermore in small-cell scenario, the throughput gain of 70% and over 5 Gbps are achieved applying multi-point transmission in the condition of two different MIMO streams transmission from a single TP as distributed MIMO instead of four MIMO streams transmission from a single TP.

Indoor and Outdoor Experiments on 5G Radio Access Using Distributed MIMO and Beamforming in 15 GHz Frequency Band

This paper presents indoor and outdoor field experimental results that clarify the 4-by-8 MIMO throughput performance when applying distributed multiple-input multiple-output (MIMO) with a narrow antenna beam tracking in the 15 GHz frequency band in the downlink of a 5G cellular radio access system. The experimental results show that throughput exceeding 15 Gbps is achieved with a high average rank of 4 at an indoor office building lobby and outdoor parking area. As for the distributed MIMO gain in terms of throughput in LoS environments, we achieve throughput gain of 39 % and 105 % in the indoor office building lobby and outdoor parking area, respectively. And also throughput gain of 15 % is achieved in N-LoS environment in office building lobby in multi-path rich environment. We also observe a significant increase of throughput and rank when changing the transmission point (TP) spacing from 0.5 to 1.5 m, while only a limited performance improvement when the TP spacing exceeds 1.5 m. Finally, the throughput performance with various TP positions was tested, and the TP locations when facing each other with a TP spacing of 50 m exhibit excellent performance exceeding 10 Gpbs.

5G Experimental Trial Achieving over 20 Gbps Using Advanced Multi-Antenna Solutions

We propose a trial concept that utilizes advanced multi-antenna solutions such as beamforming and spatial multiplexing with a massive number of antenna elements for use in a previously established trial system for the fifth generation (5G) mobile broadband communications system. Furthermore, we present experimental results showing that multi-user aggregated data rates exceeding 20 Gbps are possible in a real field environment.

Indoor experiment on 5G radio access using beam tracking at 15 GHz band

This paper presents indoor experimental results showing the achievement of 14.5 Gbps throughput performance based on 730.5 MHz bandwidth transmission when applying carrier aggregation (CA) with 8 component carriers (CCs) and 4-by-8 single-user multiple-input multiple-output (MIMO) multiplexing in the 15 GHz frequency band in the downlink of 5G cellular radio access. Beam tracking with massive MIMO is implemented in a 5G testbed to support user mobility with a narrow beam. Experimental results in an indoor multi-path rich environment show that the peak throughput is 14.5 Gbps in a line-of-sight (LoS) environment with high mobility-reference signal received power (MRSRP) and low antenna correlation. The results also show that 12.5 Gbps is achieved behind a wall in non-LOS conditions due to ceiling reflections.

Experimental evaluation on 5G radio access employing multi-user MIMO at 15 GHz band

This paper presents indoor and outdoor experimental results on the achievable throughput for downlink 8-by-16 multi user (MU)-multiple-input multiple-output (MIMO) using 2 sets of user equipment (UE) and carrier aggregation with 8 component carriers in various measurement areas for 5G radio access. In the presence of four centralized antenna units, the throughput performance is evaluated using the implemented 5G testbed for MU-MIMO operation. The experimental results show that the peak system throughput of 18.6 Gbps and 25.9 Gbps are achieved in indoor and outdoor environments. Furthermore, we confirm that to avoid interference a vertical angle exceeding 18 deg. or a horizontal angle exceeding 10.7 deg. is required between UEs to achieve the throughput of 12 Gbps for a UE when employing MU-MIMO in an outdoor open space.

Beamforming Gain Measured on a 5G Test-Bed

This paper presents measurement results from different deployments with a 5G test-bed on a 15-GHz frequency band. The beam gain with a grid-of-beam solution applied to an 8x8 element antenna array is compared with a reference wide-beam power equivalent antenna. The beamforming gain in outdoor environment is found to be large, it is in the range of 10-13 dB in line-of-sight (LoS) and 7-12 dB in non-LoS. In a reflective and rich indoor environment, the gain is as expected lower but still substantial, 5-11 dB. The potential of a hybrid analog-digital solution is also assessed as an upper bound with perfect phase coherent combination of several beams. To reach an average beamforming gain of 14 dB it is sufficient with the combination of three beams in outdoor LoS, while eight beams are required in the indoor scenario.

Experimental evaluation of advanced beam tracking with CSI acquisition for 5G radio access

This paper presents indoor and outdoor experimental results on 4-by-8 single-user (SU)-multiple-input multiple-output (MIMO) multiplexing based on 730.5 MHz bandwidth transmission when applying carrier aggregation (CA) with 8 component carriers (CCs) in a 15 GHz frequency band in the downlink of 5G cellular radio access. Beam tracking with massive MIMO is implemented in a 5G testbed to support user mobility with a narrow beam. In addition, channel state information (CSI) acquisition functionality is implemented for the scheduler to select appropriate beams. Experimental results in an indoor multi-path rich environment show the gain up to 34 % with CSI acquisition compared to the case of without CSI acquisition in a line-of-sight (LoS) environment with high rank MIMO transmission. The results also show the gain up to 55 % with CSI acquisition compared to the case of without CSI acquisition in LoS conditions due to reflections by buildings.

Field Experiments on Combination of Downlink CoMP and Smart Vertical MIMO in LTE-Advanced

This paper focuses on the combination of coordinated multipoint (CoMP) transmission and Smart Vertical (SV)-Multiple-Input Multiple-Output (MIMO) base station (BS) antenna in the LTE-Advanced downlink to analyze the synergy effect on the combination, so that it presents experimental results on the combination. We investigate the gain of CoMP joint transmission (JT) and dynamic point selection (DPS) compared to non-CoMP transmission, and install a SV-MIMO antenna as BS antennas. Field experiments, which are conducted in a urban and suburban area in Japan, show that the achievable user throughput of CoMP DPS is from 20 % to 180 % greater than that for non-CoMP transmission, and no remarkable difference between CoMP JT and CoMP DPS within 5% throughput. With implementing SV-MIMO BS antenna for combination of CoMP DPS, up to 180 % throughput gain is achieved compared to using the conventional BS antenna. Finally comparing the throughput performance over different tilt angle, there is not remarkable difference for CoMP DPS transmission in both urban and suburban area.