Detecting wireless interference

In a time where countless devices are connected to the internet wirelessly, interference is inevitable. Spectrum pollution in the Internet-of-Things (IoT) era is something all users experience—a lag in connecting to your favorite app, not being able to sync to a wireless printer, the dreaded loading circle when trying to stream your favorite show. But what if IoT devices could detect and respect the presence of other devices on a shared spectrum? This would allow for devices and users to have a seamless wireless experience.

Swarun Kumar, Anthony Rowe, and Robert Iannucci from Carnegie Mellon University’s Department of Electrical and Computer Engineering have been awarded a $1 million National Science Foundation (NSF) grant to investigate a system that allows teams of geo-distributed low-power devices to quickly and efficiently scan wide bandwidths to avert interference. 

“The core challenge is the low-power and simplicity of most IoT devices,” said Swarun Kumar, assistant professor and principal investigator. “They are narrowband and unable to sense and avoid incumbents on shared spectrum.”

The proposal presents a system designed for low-power devices to sense spectrum at minimal energy and cost, allowing these devices to behave as low-cost and distributed spectrum observatories.

Much like land and water, radio spectrum is a shared resource by many stakeholders; Wi-Fi routers, cellular companies, AM/FM radio stations, television towers, etc. Companies lease spectrum use under multi-year contracts. However, a lot of the spectrum is not used consistently, leading to significant wastage of a costly resource. What if there was a way to monitor the spectrum and signal when it’s available at a given location so that it could be leased on-the-fly when vacant? This would save companies money, and increase the speed of our devices. However, building such a spectrum monitoring infrastructure can be costly. It would need to be replicated all over the country, and it would need to scan huge swaths of spectrum, increasing the cost further.

Referred to as Swallow, this project explores the use of low-cost and low-power IoT devices to serve as spectrum monitors that are cheap and can be placed anywhere. Globally, IoT devices are projected to be deployed in tens of billions and be ubiquitous in the coming years. Rather than viewing these as yet another part of the spectrum sharing problem, this project views them as part of the solution in effectively monitoring radio spectrum.

The project’s objective, if successful, could pave a new way to manage, monitor, and better exploit spectrum—a valuable national resource—as the world embarks on high-speed wireless beyond 5-G.

The core challenge is the low-power and simplicity of most IoT devices. They are narrowband and unable to sense and avoid incumbents on shared spectrum.

Swarun Kumar, Assistant Professor, ECE

“The testbed developed through the project will serve as a vehicle for undergraduate and graduate-level projects as well as workshops for K-12 students in the city of Pittsburgh,” said Kumar. “The team has direct experience working with sensor deployments at Carnegie Mellon, the city of Pittsburgh, United States Geological Survey (USGS), and local industry partners and will leverage these connections to deploy Swallow at scale.”

The project will be implemented and evaluated on a large programmable Low-Power Wide-Area Networking testbed in the Carnegie Mellon University campus that serves large parts of the City of Pittsburgh. This award reflects NSF’s statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.