Reviewed by Alex SmithAug 24 2021
Consumers of existing 5G mobile phones might have experienced any of the following tradeoffs: attractive download speeds with extremely limited and spotty coverage, or broad and dependable coverage with the speed that is not up to the speed of existing 4G networks.
UC San Diego electrical and computer engineering PhD student Ish Jain poses with the new millimeter-wave setup that he developed. The setup improves the throughput and reliability of millimeter-wave signals. Image Credit: University of California San Diego.
Electrical engineers at the University of California San Diego integrated the best of both technologies and facilitated 5G connectivity that is not only ultra-fast but also reliable. The researchers will present their work at the ACM SIGCOMM 2021 conference to be held online from August 23rd to 27th, 2021.
The technology offers a solution to resolve a hindrance in making the high band 5G practical for the daily user. The swift wireless signals, referred to as millimeter waves, cannot travel far and are easily blocked by walls, trees, people and other barriers.
Existing high band 5G systems communicate data by transmitting a laser-like millimeter-wave beam between a base station and a receiver, for instance, a user’s phone. The issue arises when something or someone interrupts the beam path, which completely blocks the connection.
Relying on a single beam creates a single point of failure.
Dinesh Bharadia, Study Senior Author and Professor, Electrical and Computer Engineering, Jacobs School of Engineering, University of California San Diego
Two Beams are Better than One
Bharadia and his colleagues are part of the UC San Diego Center for Wireless Communications and provided an intelligent solution. It proposes to split a laser-like millimeter-wave beam into multiple laser-like beams, where each beam is made to take a different path to the receiver for the base station.
The concept is to enhance the odds that at least one beam reaches the receiver when there is an obstacle in the path.
The researchers developed a system capable of performing this and verified it inside an office and outside a building on campus. The system offered a high throughput connection (up to 800 Mbps) with 100% reliability, implying that the signal did not fall or lose strength as the user walked around the obstacles like walls, desks and outdoor sculptures. The system offered connectivity of up to 80 m (262 ft) away in outdoor tests.
The researchers developed the system by creating a set of new algorithms. One algorithm initially directs the base station to divide the beam into several paths. A few of these paths take a direct shot from the base station and the receiver. Some paths opt for an indirect route, where the beams tend to bounce off the surface called reflectors. These are the surfaces that reflect millimeter waves like glass, metal, drywall, or concrete, to reach the receiver.
Then, the algorithm analyzes the best path in the given surrounding. It later corrects the angle, power and phase of each beam so that when they reach the receiver, they are merged constructively to develop a strong, high-throughput and high-quality signal. This technique increases the number of beams and results in a stronger signal.
You would think that splitting the beam would reduce the throughput or quality of the signal. 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.
Dinesh Bharadia, Study Senior Author and Professor, Electrical and Computer Engineering, Jacobs School of Engineering, University of California San Diego
The other algorithm helps maintain the connection when the user moves around or when another user interrupts the path. During these occurrences, the beams tend to get misaligned. The algorithm resolved this issue by constantly tracking the movement of the user and adjusting all the beam parameters.
The algorithm was implemented by the scientists on advanced hardware that was developed in the laboratory.
You don’t need any new hardware to do this. Our algorithms are all compliant with current 5G protocols.
Ish Jain, Study First Author, Electrical and Computer Engineering PhD Student, University of California San Diego
The hardware includes a small base station and receiver. The base station is loaded with a phased array developed in the laboratory of Gabriel Rebeiz. Rebeiz is a professor of electrical and computer engineering at the University of California San Diego. He is also an expert in the phased array for 5G and 6G communications and also a member of the Center for Wireless Communication of the University.
The researchers are now working to scale up the system, making it capable of hosting multiple users. This study was financially supported by the National Science Foundation (grant 1925767).
Journal Reference:
Jain, I. K., et al. (2021) Two beams are better than one: towards reliable and high throughput mmWave links. SIGCOMM ’21: Proceedings of the 2021 ACM SIGCOMM 2021 Conference. doi.org/10.1145/3452296.3472924.