Novel system could bring ultra-fast 5G to homes and workplaces

The technology, developed by electrical engineers at the University of California (UC) San Diego, presents a solution to overcome a roadblock to making high-band 5G practical for the everyday user: millimetre-wave wireless signals  cannot travel far and are easily blocked by walls, people, trees and other obstacles.

Today’s high-band 5G systems communicate data by sending one millimetre-wave beam between a base station and a receiver – for example, a user’s phone. But if something or someone obstructs that beam’s path, then the connection gets blocked completely.

“Relying on a single beam creates a single point of failure,” explained Dinesh Bharadia, a professor of electrical and computer engineering at the UC San Diego Jacobs School of Engineering.

To tackle this, the research team came up with a solution - split the one laser-like millimetre-wave beam into multiple beams, and have each beam take a different path from the base station to the receiver.

The idea was to improve the chances that at least one beam reaches the receiver when an obstacle is in the way. So, the researchers created a system capable of doing this and tested it inside an office and outside a building on campus.

According to the researchers, the system provided a high-throughput connection (up to 800Mbps) with 100 per cent reliability, so the signal didn’t drop or lose strength as the user moved around obstacles like desks, walls, and outdoor sculptures. In outdoor tests, the system provided connectivity up to 80m away.

To create the system, the researchers developed a set of new algorithms. One algorithm first instructs the base station to split the beam into multiple paths. Some of these paths take a direct shot from the base station and the receiver; and some paths take an indirect route, where the beams bounce off what are called reflectors – surfaces in the environment that reflect millimetre-waves like glass, metal, concrete or partition wall – to get to the receiver.

The algorithm learns which are the best paths in a particular environment and optimises the angle, phase and power of each beam so that when they arrive at the receiver, they combine constructively to create a strong, quality, and high throughput signal. With this approach, more beams result in a stronger signal.

“You would think that splitting the beam would reduce the throughput or quality of the signal,” Bharadia said. “But with how 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 team added that the other algorithm maintains the connection when a user moves around or another user steps in the way. When these things happen, the beams get misaligned. The algorithm overcomes this issue by continuously tracking the user’s movement and realigning all the beam parameters.

The researchers implemented their algorithms on hardware, which comprises a small base station and receiver, that they developed in a lab at the university’s Center for Wireless Communications. “You don’t need any new hardware to do this,” said Ish Jain, an electrical and computer engineering PhD student in Bharadia’s lab. “Our algorithms are all compliant with current 5G protocols.”

The team is now working on scaling its system to accommodate multiple users.