NTT DOCOMO in partnership with NEC has recently completed 5G transmission of a 4.5GHz signal using beamforming and inter-base station coordination to reduce interference for 5.5 Gbps throughput to eight mobile terminals.
The test, conducted in Kawasaki, Japan, used digital signal processing between base stations, which were equipped with signal processing units and massive-element antennas, to coordinate beamforming between base stations. Simultaneously, 5G communication with eight mobile terminals was achieved.
The test verified the feasibility of beamforming through coordination of small, optical-feeder-type base stations equipped with 128-element antennas and digital signal processing units, which were connected via optical fiber.
Antennas of adjacent base stations sometimes cause large interference and reduce data rate, but this test used beamforming and digital signal processing to mutually cancel out interference.
The solution will enable multiple antennas to be installed more flexibly for higher-capacity 5G communications in dense urban areas.
