A Better Bluetooth for Wearables Ditches Electromagnetic Radiation for a Big Battery Boost

Researchers from the Wearable Technologies Lab at the University of Sussex claim to have developed a new approach to short-range communications which offers a dramatic efficiency improvement over Bluetooth — by doing away with electromagnetic modulation altogether.

"We no longer need to rely on electromagnetic modulation, which is inherently battery hungry," claims Daniel Roggen, a professor of engineering and design and a co-author on the team's paper. "We can improve the battery life of wearable technology and home assistants, for example, by using electric field modulation instead of Bluetooth. This solution will not only make our lives much more efficient, but it also opens novel opportunities to interact with devices in smart homes."

Traditional wireless communications technologies are based on electromagnetic modulation in the radio-frequency spectrum, an approach which has barely changed since its development over 125 years ago. Originally made for long-range wireless communication, the same technology powers high-speed shorter-range communications systems like Bluetooth and Wi-Fi — but, the researchers claim, it's ill-suited to wearable devices for one simple reason: its high power draw.

By switching electromagnetic modulation for electric field modulation, the team claims, it's possible to replace Bluetooth with something considerably more energy-efficient. While the team isn't the first to come up with the concept, it claims to have advanced the state of the art by offering fully-wireless non-contact transmission and reception over electric field modulation at distances up to 75cm (around 30 inches) with an acceptable error rate.

To prove the concept, the team integrated the electric field modulation system into a pair of commercial headphones, designed to receive a binary frequency-shift keying (BFSK) audio signal from a nearby transmitter. While the quality can't match Bluetooth quite yet — delivering eight-bit monaural audio at 16kHz, for a throughput of 128kb/s — it's a promising first step to improving the battery life and performance of future wearables, with the researchers proposing further uses including the transmission of authentication credentials to smart lock systems.

“The technology is also low cost," Roggen claims, "meaning it could be rolled out to society quickly and easily. If this were mass produced, the solution can be miniaturized to a single chip and cost just a few pence per device, meaning that it could be used in all devices in the not-too-distant future."

The team's work has been published in the Proceedings of the IEEE International Conference on Pervasive Computing and Communications 2023 (PerCom '23) under closed-access terms; the University has confirmed that it is seeking "industrial partners" to miniaturize the technology with a view to commercialization.