NEC has successfully tested a new digital beamforming transmission method that uses a massive-element active antenna base station and 28 GHz band spectrum.
The demo is described as the simultaneous beamforming transmission (four multi-user MIMO) from a single massive-element active antenna system (AAS) to four terminals. NEC achieved a 3.1 Gbps cell throughput by applying a frequency bandwidth of 300 MHz.
NEC said its massive-element AAS, supporting a 28 GHz band, adopts a fully digital control system, which improves the precision of beamforming. The fully digital control system enables simultaneous beamforming in multiple directions from a single massive-element AAS unit and efficiently implements high-speed and high-capacity communication without interfering with adjacent users through spatial multiplexing.
The beamforming takes into account multipath, a non-direct wave signal, and moderately adjusts beam directions as needed. It also cancels out interference through multipath and reduces performance deterioration caused by inter-cell interference.
NEC enables its advanced beamforming without digital/analog signal and frequency converters. Instead, the massive-element AAS adopts a fully digital control system with less power and more compact conversion functions.
“In order to effectively implement sophisticated services that apply 5G features from 2020 onward, it is essential to utilize 28 GHz and other high frequency radio bands, which enable the securing of wide bandwidth, and the utilization of beamforming,” said Katsumi Tanoue, Deputy General Manager, Wireless Access Solution Division, NEC Corporation. “Moving forward, NEC will continue its efforts in development and demonstration tests for a massive-element active antenna base station system that delivers high speed, high capacity and massive connectivity.”
