Japan’s largest mobile operator NTT Docomo claimed its drive to launch 5G by 2020 gained further momentum after it completed pre-standard 5G trials in Japan with two of its vendor partners.
In a joint trial with Samsung last week at the Fuji Speedway, the operator achieved a data rate of more than 2.5Gb/s with a mobile device that was in a vehicle travelling at 150km/h. Transmissions were conducted on the 28GHz high-frequency band.
The problem of high path-loss of high-frequency radio signals, which occurs in data transmission to fast-moving devices, was overcome using massive multiple-input multiple-output (MIMO) technologies that incorporate beamforming, which concentrates radio waves in a specific direction, and beam tracking, which adjusts the beam according to the fast-moving mobile device’s location, the operator said in a statement.
In a separate test last month, Docomo carried out a large-scale data-transmission trial with Huawei on a field covering 100,000 square metres in Yokohama. The trial involved 23 simultaneously connected mobile devices and achieved a cumulative data throughput of 11.29Gb/s and latency below 0.5ms using the 4.5GHz band.
The trial combined multi-user MIMO (MU-MIMO) technology for simultaneous multiple access and a precoding algorithm that optimises signals for maximised performance and also limits inter-user interference.
The operator plans to launch commercial 5G services in time for the 2020 Summer Olympics in Tokyo. It will expand 5G trials next year (with Ericsson and Intel) and is confident that average data rates of 1Gb/s will be available by 2020.