Mitsubishi Electric and NTT DoCoMo announced today that they have achieved a 5G proof of concept for 27 Gbps and 25 Gbps maximum throughputs via one mobile terminal over communication distances of 10m and 100m, respectively, using the 28GHz band.
The demonstration was conducted during joint outdoor field trials using 28-GHz massive-element antenna systems and 16-beam spatial-multiplexing technology with 500 MHz bandwidth. The trial took place in Kamakura, Kanagawa Prefecture Japan in September 2018.
A peak data rate of 20 Gbps is required for 5G mobile communications. One technology that promises to meet this need is massive-element antenna systems technology, which enables multi-beam spatial multiplexing, where multiple data streams can be transmitted in parallel to mobile terminals. Realizing this technology, however, has involved two challenges: implementation of a massive-element antenna array that clusters large numbers of antenna elements for high-precision beamforming, and mitigation of inter-beam interference.
Mitsubishi Electric and DoCoMo have jointly undertaken research to develop and validate a massive-element antenna system enabling 16-beam spatial multiplexing.
In 4G systems, it has not been possible to establish high data-rate communication for a single mobile terminal using more than four streams. Mitsubishi Electric and DoCoMo carried out 28-GHz-band outdoor field trials to verify the feasibility of 16-beam spatial multiplexing in line-of-sight conditions, where massive-element base-station antennas installed on the wall of a building directed beams to mobile-terminal antennas installed on the rooftop of a vehicle. The mobile terminal moved along two different streets. The distance of one mobile terminal was 10m from the base station and the distance for the other was 100m.
The developed beamforming technology enables beams to track a mobile terminal by switching the preset beam. The inter-beam interference reduction technology estimates the channel at the base station and controls the transmitting signal to adaptively reduce inter-beam interference as channel conditions over time. Together, the two technologies enable 16-beam spatial multiplexing in outdoor mobile environments.
The trials achieved what DoCoMo clains is the world’s first successful wireless downlink transmissions at data rates of 27 Gbps and 25 Gbps when the distance between the base station and the mobile terminal was 10m and 100m, respectively. The achieved peak data rates correspond to spectral efficiency of 67bps/Hz.