Beamforming--a novel signal processing technique--plays a key role at the frontier of a number of industries, from telecommunications to radar systems and acoustic engineering. Conventionally, when a signal emanates from an antenna, its energy disperses widely, resulting in a large coverage area but with diminished intensity. However, beamforming makes it possible to channel the signal's energy in a targeted direction, thereby enhancing signal quality and range while minimizing interference.

The technology is primarily realized via two approaches--Analog and Digital Beamforming. Analog Beamforming involves using an array of distinct antenna elements, each possessing adjustable phase and amplitude. This results in constructive interference in the desired direction and destructive interference elsewhere. While this method is simple, it lacks the agility to adapt to changing environments. Conversely, Digital Beamforming processes the signal received by an antenna array digitally via algorithms, offering enhanced flexibility since the beam can be dynamically altered to suit varying environmental conditions.

Beamforming delivers numerous benefits. By directing energy in a specific direction, it amplifies signal strength and extends the communication range, thus improving reliability. It also mitigates interference from other sources by amplifying the desired signal and minimizing unwanted signals from varying directions. Furthermore, beamforming facilitates spatial multiplexing, enabling simultaneous transmission of multiple independent data streams in different directions, significantly augmenting a communication system's data capacity. It has potential applications in a number of areas, including wireless communication systems like Wi-Fi and cellular networks, precise object detection and tracking in radar systems, and efficient noise cancellation or voice recognition in microphone arrays. Even medical imaging technologies like ultrasound leverage it for high-resolution, clear images.

A significant breakthrough was made recently when NTT, together with a team headed by Professor Kenichi Okada from the Tokyo Institute of Technology ("Tokyo Tech"), developed a phased array transmission module for the 6th generation mobile communication system (6G) in the 300GHz band. This advancement marks the world's first successful high-speed wireless data transmission in the 300GHz band using beamforming and has opened the possibilities for instantaneous transfer of ultra-high capacity data to a mobile receiving terminal.

Operating in the 300GHz band wave poses several challenges, including high wave loss during propagation through space. However, these challenges were overcome by focusing and radiating wave energy in the direction of the receiving terminal using beamforming technology.

Each research partner worked to its strengths in developing high-speed wireless data transmission using 300GHz beamforming. Tokyo Tech employed a highly integrated Complementary Metal-Oxide-Semiconductor Integrated Circuit (CMOS-IC) equipped with frequency conversion circuits, control circuits, and more. At the same time, NTT developed an Indium Phosphide Integrated Circuit (InP-IC) integrated with a high-power amp circuit and antenna using its unique Indium Phosphide Heterojunction Bipolar Transistor (InP HBT) technology.

Tokyo Tech and NTT assembled a 4-element phased array transmission module, integrating the CMOS-IC and InP-IC on the same printed circuit board. This module achieved a maximum data rate of 30Gbps at a communication distance of 50cm, with a 36-degree directionality control range.

The partners' breakthrough offers the potential for future developments expected in near-distance mobile communications, such as the KIOSK model and Femtocell, which are potential applications for 6G. Next steps involve demonstrating two-dimensional beamforming through two-dimensional arraying, expanding the communication distance by increasing the number of arrays, and developing receiving modules tailored to the usage application. Eventually, Tokyo Tech and NTT aim to enable wireless communication with more than ten times the transmission capacity of conventional systems.

For further information on NTT's beamforming research, click here:
https://group.ntt/en/newsrelease/2021/02/05/210205c.html

NTT--Innovating the Future of Communication