Research furthers knowledge of ultralow-power wireless networks

Research being conducted at the University of Arkansas will improve wireless sensors deployed in remote areas where these systems must rely on batteries or energy-harvesting devices for power. The university will receive $279,425 over three years from the National Science Foundation to create distortion-tolerant communications for wireless networks that use very little power.

“Ultralow power consumption is one of the most formidable challenges faced by the next generation of wireless sensing systems,” said Jingxian Wu, assistant professor of electrical engineering, who will conduct the research. “These systems will need to operate without interruption for multiple years and with extremely limited battery capacity or limited ability to scavenge energy from other devices. This is why the NSF was interested in our research.”

Ultralow-power wireless devices use batteries or energy-harvesting systems like solar panels for power. The less power the device uses, the longer it can operate without recharging. Sensors are often deployed in remote areas to monitor subjects such as water quality, animal health and the condition of tunnels, buildings and bridges, and are expected to operate without interruption for long periods of time without changing batteries. By reducing the power consumption, the device can operate for long periods of time without human intervention.

Distortion is deemed to have occurred during data transfer if the received message is different from the transmitted message. In digital communication systems, the data are transmitted in the form of zeroes and ones. Noise and interference during the transmission process can result in a zero being received as a one, and vice versa. Distortion-free communication is required for critical data or software, such as computer games, where any distortion might render the software non-operational. Data such as pictures, music and videos can tolerate some degree of distortion as humans may not be able to perceive some of the features.

While conventional research on wireless communication technology focuses on minimising distortion, the University of Arkansas research team will work with distortion-tolerant systems. These systems allow for controlled distortion, instead of limiting or minimising distortion, which uses less power than conventional technology.

“If we accept the fact that distortion is inevitable in practical communication systems, why not directly design a system that is naturally tolerant to distortion?” Wu said. “Allowing distortion instead of minimising it, our proposed distortion-tolerant communication can operate in rate levels beyond the constraints imposed by Shannon channel capacity.” (Shannon channel capacity is the maximum rate at which distortion-free information can be transmitted over a communication channel.)

Wu’s project aims to advance the knowledge of ultralow-power wireless networks. The research will involve constructing and testing theories, designing tools to enable distortion-tolerant technologies and design, and developing prototype networks.

Wu and his colleagues anticipate their work will accelerate the widespread deployment of ultralow-power wireless networks used for surveillance, environmental and structure monitoring, and biomedical sensing. They could be used to provide early warnings to prevent events such as structural failures and improve public safety and homeland security.