Splitting and bouncing beams boosts 5G speed and coverage
There are two main versions of 5G technology, depending on what you prioritize – speed or coverage. But now, engineers at the University of California San Diego have found a way to get the best of both worlds, using an algorithm to bounce faster signals around obstacles.
As more people get phones with 5G connectivity, you might be noticing one of two problems. Either it doesn’t seem much faster than 4G, or it’s very fast as long as you stand perfectly still and don’t go indoors. The difference could come down to which version of the technology your service provider and your phone itself are tapping into.
The two technologies in use are known as mmWave and sub-6. The latter, as its name suggests, uses frequencies below 6 GHz, which can penetrate obstacles and get into buildings easily, plus it works with existing infrastructure – but as such its speeds feel decidedly last-gen. On the other hand, mmWave transmits at very high frequencies, which is great for sending a lot of data at once – as long as you don’t need it to go too far, or through walls.
For the new study, the UC San Diego researchers set out to find a way to combine the speeds of mmWave with the coverage of sub-6. Normally, a mmWave signal is sent as one laser-focused beam between a base station and a receiver, such as a user’s phone. But of course, if this one beam is interrupted, say by a person, an object or a wall, the signal is lost.
So the team decided to try splitting that single beam into several, and having them take different paths to the receiver. A new set of specialized algorithms tell the base station to do this, so that some beams go straight towards the receiver while others are directed to bounce off surfaces like glass, metal, concrete or drywall to get to the device. The algorithms can learn the best paths, and optimize the angle, phase and power of each beam to improve the signal.
“You would think that splitting the beam would reduce the throughput or quality of the signal,” says Dinesh Bharadia, senior author of the study. “But with the way that we’ve designed our algorithms, it turns out mathematically that our multi-beam system gives you a higher throughput while transmitting the same amount of power overall as a single-beam system.”
The researchers tested the system, which they call mmReliable, inside an office building as well as outdoors. In the indoor tests, mmReliable was able to continuously beam a high-speed connection of 800 Mbps to a phone without ever dropping out, even as a user walked around behind desks, walls and other obstacles. Outdoors, the system provided a connection up to 80 m (262.5 ft) away.
The team says that this system could be rolled out to existing 5G infrastructure, since it doesn’t require any new hardware. Other experiments have boosted 5G speeds by tapping into some 4G frequencies.
The research will be presented at the ACM SIGCOMM 2021 conference this week.
Source: UC San Diego