MIMO technology triples the number of concurrent connections and transmission capacity

NEC announced that it has verified that distributed MIMO can achieve multi-terminal concurrent connections and increase transmission capacity in the 28GHz millimeter wave band in an actual office environment. Compared with the case where distributed MIMO is not used, there is less interference from obstructions, and the number of concurrent connections and transmission capacity have increased by about 3 times.

This is the industry's first application of a distributed MIMO system in the millimeter wave band in an office environment. It is expected that this will contribute to the construction of a more convenient 5G environment that can achieve concurrent multi-connections in the future.

The 5G network, which uses the Sub-6GHz and millimeter wave bands, is expected to achieve network performance and related services that are more than 10 times larger than 4G, such as large capacity, high throughput, low latency, and multiple connections. Japan has begun deploying it this year.

The sub-6GHz band is narrower than the available frequency band of the millimeter wave band, so in order to increase capacity, massive MIMO was introduced to expand the number of terminals that can be connected concurrently. Similarly, applying massive MIMO to the millimeter wave band can achieve greater capacity and concurrent multi-point connections, and is considered to be the best choice when each terminal requires high transmission capacity, such as indoors and in stadiums and auditoriums. High-density places.

Further capacity expansion through combination of spatial multiplexing and mmWave broadband transmission

However, in the millimeter wave frequency band, due to the characteristics of radio waves, such as short wavelength, large attenuation caused by reflection and shielding, etc., it is easily affected by obstructions and difficult to perform spatial multiplexing. These are challenges faced when applying massive MIMO.

NEC has been leading the industry in digital beamforming technology and has commercialized the application technology of massive MIMO in the Sub-6GHz band. In addition, NEC has developed and carried out verification activities for digital coordination technology between antenna elements distributed in the millimeter wave band to solve the propagation path obstruction and diffraction problems existing in indoor mobile communications.

Based on the above background, NEC conducted propagation and transmission experiments on the radio unit (RU) of the 28GHz band base station using distributed MIMO technology in an actual office environment, and actually proved that stable transmission can be achieved in a shielded environment while achieving multi-terminal concurrent connections and greater capacity. Specifically, NEC has developed a technology that can effectively calibrate phase and amplitude to solve the problem of calibration and coordination of phase and amplitude between distributed antennas. The results show that the number of concurrent connections and transmission capacity increased by about three times compared to the case where distributed MIMO was not used.

In order to achieve stable and high-speed transmission speeds in environments where obstacles such as offices make it difficult for millimeter waves to communicate stably and where terminals are densely deployed, NEC will continue to conduct actual verification of 5G environments and contribute to the popularization and development of mobile access networks in the millimeter wave frequency band.

NEC will continue to create new social value by providing "NEC Smart Connectivity" that intelligently connects data generated by people and things beyond industry boundaries.