NEC announced that it has completed joint verification trials of its massive-element Active Antenna System (AAS) supporting the low-SHF band (3 GHz to 6 GHz) with NTT DoCoMo.
The trials, which were conducted in central Tokyo and Kanagawa Prefecture, employed the massive MIMO AAS in base stations for both outdoor environments – where radio waves are reflected or diffracted due to buildings, utility poles, vehicles and people – and indoor environments, which also include many obstacles, such as columns and walls.
NEC says its AAS adopts fully-digitized antenna beam control technology, which improves the precision of beam forming. While transmitting beams to the target mobile handsets, it is capable of forming beams that counteract interfering signals using the multi-path. It can also form beams that improve communication quality by efficiently combining the multi-path of its own signals with the direct waves.
NEC’s AAS enables concurrent communication with several handsets, even if they are close to each other, while maintaining high communication quality. In the trials, NEC says it proved that use of the AAS can result in improved capacity and quality of communication between a base station and handsets, while confirming that spectral efficiency was reliably maintained at a level roughly eight times higher than that achieved by LTE in indoor environments (compared with 2 spatial multiplexing in LTE).
Takehiro Nakamura, managing director of the 5G Laboratory at NTT DoCoMo, said, “We expect NEC to continue pursuing high-speed, large-capacity communication using the low-SFH band and contributing to our commercialization of 5G.”
“Among the high frequency bands, we are working especially hard to put the low-SHF band into practical use, since it is expected to enter into commercial use around 2020,” said Nozomu Watanabe, GM of NEC’s Mobile Radio Access Network Division. “We will capitalize on the results of these trials as we continue to work together with NTT DoCoMo and other communication carriers, aiming at the practical application of 5G.”