Testing coordination technology between cells

NEC has announced the start of verification experiments to achieve 5G wireless communications in cooperation with NTT DOCOMO, INC. In these experiments, a massive-element Active Antenna System (AAS) base station system is able to achieve coordinated control between Distribution Units (DUs). It belongs to a Centralized-Radio Access Network (C-RAN) configuration, which enables a Central Unit (CU) to control multiple DUs.

Mechanisms

In the low SHF band AAS base station system, the CU exchanges information on terminals connected to different DUs. DUs then form directional signals while performing coordination control between DUs.

This improves the throughput of terminals located near the boundary of DUs’ communication ranges when compared to conventional throughput. Besides, it achieves stable, high-quality communication regardless of location.

When adjacent terminals are near the communication range boundary of several DUs and each forms a beam independently for each terminal communicating with it, the quality of communication decreases. This includes reduced video download speeds due to radio wave interference between the DUs.

For 5G, the interference between DUs will become a major challenge.

Verification Experiments

In these verification experiments, under a range of conditions, such as suburbs and city centers, the quality of down streaming is measured by the presence or absence of coordination control between DUs.

This happens when adjacent terminals are near the communication range boundaries of two DUs that are connected to the CU.

In one set of verification experiments, there was not the performance of coordination control; this has resulted in significant interference and a decrease in the quality of communications.

This is because of the appearance of beams and the performance of down streaming without the influence of terminals controlled by other DU.

However, in other experiments, when there is the performance of coordination control, there is also the formation of beams through coordination between DUs.

This prevents a decrease in the quality of communication caused by radio wave interference. It also improves the downlink throughput by 50%. Moreover, stable and high-quality communications can be available regardless of location.

“NEC is contributing to the roll-out of 5G in the near future. It includes these verification trials using the AAS base station system,” said Kenichi Ito, Deputy General Manager, Wireless Network Development Division, NEC Corporation.

“We aim to drive the advancement of high-speed, large capacity communications and sophisticated service functions.”

NEC will introduce 5G initiatives in Hall 3, Stand 3M30 at Mobile World Congress 2018 in Barcelona, Spain.