5G beamforming transceiver is more accurate, less expensive

The highest speeds offered by 5G will come in the form of millimetre waves. The cellular communications that people know today generally don't use them because those high frequencies don't travel very far and can easily get blocked by trees or other obstacles in a path. So, when rolling out 5G, it will be necessary to have more antennas spaced closer together to achieve the desired results.

For example, network operators in Japan and Korea may need up to four times the cell sites currently used to provide nationwide coverage, not to mention more complex antenna designs. 5G communications are questionable at best for now.

However, a team at the Tokyo Institute of Technology and NEC Japan teamed up to build a transceiver that they say could pave the way to improved 5G communications.

What makes this transceiver different?
Their achievement is a 39 GHz transceiver, which sets it apart from most of the other transceivers in development. Those are typically 28 GHz systems. The researchers believe 39 GHz transceivers will eventually be instrumental in enabling 5G communications in some parts of the world.

The transceiver has a phased-array design and includes an integrated phase calibration component. That feature plays a crucial role in better beamforming accuracy, plus improved signal strength and reduced radiation. Beamforming technology detects the location of a device and sends a signal in the direction that's optimal for it, instead of distributing the signal in all directions.

Many people initially hear about beamforming technology associated with WiFi technology. More specifically, it gives everyone access to faster, stronger and longer-range WiFi signals.

Scientists were also pleased when they tested the signal strength of the transceiver's 64 antennas.

The researchers tested it by measuring the maximum equivalent isotropic radiated power (EIRP) of an antenna. They found that the device had a maximum EIRP of 53 decibels per meter.

Superior to other transceivers for gain variation
When the team worked with the phase calibration aspect, they noted that it had a low root-mean-square (RMS) phase error of 0.08 degrees, which is a reflection of the average phase error against the ideal reference signal.

The transceivers developed so far typically have at least a 1 decibel (dB) gain variation, whereby gain is the loudness of the input channel. But this new transceiver only shows a 0.04 dB gain variation over the full 360-degree tuning range.

A low-cost option for future 5G technologies
The researchers made this transceiver through a standard 65-nanometre complementary metal-oxide-semiconductor (CMOS) process. CMOS is the main processing method used when creating integrated circuits. They noted that the transceiver has reasonably priced silicon components that could make the technology well-suited for mass production.

During indoor tests of the transceiver, the researchers used a special chamber that's free from echoes. The experiments showed that the transceiver supports wireless transmissions of a 400 MHz signal with 64 quadrature amplitude modulation (QAM).

The scientists said that by increasing the scale of the array — the electrically steerable antennas — they could accomplish better communication distances that exceed the results of the tests carried out so far in the lab. The body responsible for 5G standards completed them in 2018, which set the stage for further developments and experimentation with 5G.

Concerning this transceiver, the researchers recently presented their findings at a symposium about radio frequency integrated circuits in Boston. Moving forward, the goal is to develop the device further to get it ready for potential use in smartphones and other connected devices. 

Working on a known issue
The people involved in improving 5G technologies typically know that there are many challenges to overcome when making 5G communications the best they can be.

This transceiver is an impressive achievement that could promote better accuracy while potentially offering conclusions that could inform work on upcoming projects by these and other groups involved with 5G tech.