Outdoor Experiments on 5G Radio Access in 5G Trial Site Using Core Network in 28-GHz Frequency Band.

This paper presents outdoor field experimental results in the 28-GHz frequency band of a 5G radio access system where base stations (BSs) and a core network are installed on buildings to deploy a 5G trial area in the Tokyo Odaiba waterfront area as a 5G trial site. This is the first report of a 5G trial in a realistic urban deployment in an approximate 1 square kilometer area using a single 5G network. In this trial area, a variety of key 5G technologies are evaluated such as the peak data rate and throughput performance, 5G coverage area, BS and mobile station (MS) massive multiple-input multiple-output antennas for beamforming and tracking, intra-and inter-baseband unit handover employing the high frequency of 28 GHz, and the wide frequency bandwidth of 400 MHz in a realistic urban deployment. Results show that coverage is provided for 88% of the assessed drive route and the downlink throughput of 650 Mbps is achieved for 80% of the route. As indicated when buildings block the radio signal, line of sight (LoS) or non-LoS (NLoS) conditions are critical for signal propagation in the 28-GHz frequency band. To improve coverage in NLoS areas, a portable BS using a wireless backhaul system is installed in the trial area. With the portable BS, the corresponding coverage area is increased from 50% to 83% along the assessed drive route resulting in improved downlink throughput from 600 Mbps to 660 Mbps, and 250 Mbps to 280 Mbps in the uplink.