UVA Electrical Engineers Demonstrate That Strong and Weak Transmitters Can Share Radio Frequency Without Coordinationmkw3a@virginia.edu
From smart homes and digital health to advanced manufacturing and precision agriculture, 5G+ and its associated applications will soon demand ubiquitous connectivity for billions of wireless devices. Anticipating additional strain on the wireless spectrum, the search is on for innovative frequency-sharing methods that enable seamless cohabitation of legacy and new users.
A team at the University of Virginia School of Engineering and Applied Science has made progress on this front: It has demonstrated a new signal-processing method that provides a high quality of service to users whose signals are very weak. Experimenting with software-defined radio transmissions of strong and weak signals simultaneously over the same frequency, the team discovered a way to allow a receiver to detect the weaker signal without any coordination between the two transmitters.
Nikos Sidiropoulos, Louis T. Rader Professor and chair of UVA’s Charles L. Brown Department of Electrical and Computer Engineering, leads the team. Sidiropoulos earned a three-year grant from the National Science Foundation’s Electrical, Communications and Cyber Systems division to enable efficient and seamless short-range communication free of disturbance from much stronger transmitters. The research extends his work on statistical signal processing, machine learning and matrix theory, as well as practical communications engineering.
“Picture yourself entering a parlor where two people are already involved in a loud conversation,” Sidiropoulos said. “As you quietly engage the person closest to you, you want that person to tune out the loud conversation to understand your whispers.”
A congested wireless spectrum is similar to the parlor: The strongest signals are the loudest. When a strong transmitter, such as a radio or TV station, occupies a certain spectrum band or frequency, the weaker, short-range users run into disturbance when trying to use that same frequency. To avoid such a disturbance, the weaker user has to coordinate its transmissions, listening in on the spectrum band it wants to use to make sure it’s clear before it sends its own signal.
Salah Ibrahim, who earned his doctorate in electrical engineering this year, teamed up with Paris Karakasis, a Ph.D. student advised by Sidiropoulos, and Ahmed Hussain, a third-year computer engineering and physics major, to test a new approach using software-defined radio. Karakasis learned how to operate software-defined radios during his undergraduate program at the Technical University of Crete.