NTT Docomo says a 5G trial it conducted with Nokia Networks at the Roppongi Hills high-rise complex in Tokyo on Oct 13 achieved ultra-high-speed data transmission in excess of 2Gbps. The trial used millimeter-wavelength signals with an extremely high frequency of 70GHz, a key development for the eventual commercial use of 5G wireless technology in actual-use environments.
To date, no test had achieved a 5G data transmission in a commercial complex, such as a shopping mall, due to problems with base stations being out of line of sight and diffused reflections causing the attenuation of highly directional millimeter signals. This time, however, the trial was successful thanks to the use of two new technologies: beamforming, which focuses radio waves in a specific direction, and beam tracking to control beam direction according to the mobile device's location.
Also, in a separate trial that Docomo conducted with Samsung Electronics in Suwon, South Korea, on Nov 12, a maximum data-receiving speed of more than 2.5Gbps was achieved in a vehicle travelling with a speed of 60km/h. The trial used a 28GHz high-frequency signal in combination with beamforming with a high number of antenna elements and beam tracking.
Other trials conducted recently by Docomo in collaboration with vendors include: Docomo and Ericsson verified the feasibility of massive multiple-input multiple-output (MIMO) technology by achieving a real-time data-receiving speed of more than 10Gbps using Ericsson 5G radio prototypes with a 15GHz frequency band on Nov 19.
Docomo and Fujitsu confirmed a multi-base-station cooperative transmission system by achieving a data-receiving speed of over 11Gbps in total of four mobile devices with a 4.6GHz signal on Oct 26.
An outdoor data transmission trial conducted by Docomo, Docomo Beijing Communications Laboratories and Huawei Technologies achieved on Nov 18 a multi-user MIMO (MU-MIMO) transmission of 43.9bps/Hz/cell, which was 3.6-times more efficient than past outdoor trials of LTE-Advanced based MU-MIMO technology.
Docomo said it has been collaborating directly with a number of world-leading vendors in trials and development of 5G mobile communication technologies since May 2014.© Japan Today