Building ultra-low power wireless networks

Aug 29, 2012
Jingxian Wu, University of Arkansas.

(Phys.org)—Engineering researchers at the University of Arkansas have received funding from the National Science Foundation to create distortion-tolerant communications for wireless networks that use very little power. The research will improve wireless sensors deployed in remote areas where these systems must rely on batteries or energy-harvesting devices for power.

"Ultra-low is one of the most formidable challenges faced by the next generation of wireless sensing systems," said Jingxian Wu, assistant professor of . "These systems will need to operate without for multiple years and with extremely limited or limited ability to scavenge energy from other devices. This is why the NSF was interested in our research."

Ultra-low power wireless communication devices are powered by batteries or energy harvesting devices such as . The lower the power consumption, the longer the device can operate without recharging. This is especially important for , where the sensors are often deployed in remote areas to monitor items such as water quality, the health of animals and the condition of tunnels, buildings and bridges. These networks are expected to operate without interruption over extremely long periods of time without changing batteries. Therefore, it is important to reduce the power consumption so the device can operate for long periods without .

During data transfer, distortion occurs 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. Due to noise and interference during the transmission process, the receiver might receive a zero when a one was transmitted or vice versa. Some critical data or software, such as computer games, requires distortion-free communication. With these systems, any distortion might make the software nonoperational. Other data, such as pictures, music and videos, can tolerate some distortion because human perception might not be sensitive to some of the features.

Conventional research on wireless communication technologies focuses on minimizing distortion through various methods and designs. Conversely, Wu and doctoral student Ning Sun work with distortion-tolerant systems. Rather than limiting or minimizing distortion, their wireless systems allow for controlled distortion, which requires less power than conventional technologies.

"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 minimizing 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.

The goal of Wu's research project generally is to advance the knowledge of ultra-low power . He and his colleagues will construct and test theories, design tools to enable distortion-tolerant technologies and design and develop prototype networks. Their theories exploit the unique features of wireless monitoring systems, such as delay-tolerance, distortion-tolerance, low data rate and spatial data correlation, all of which provide more freedom in network design.

The researchers' work will accelerate the widespread deployment of ultra-low power wireless networks used for surveillance, environmental and structure monitoring, and biomedical sensing. These applications have the ability to provide early warnings to prevent catastrophic events, such as structural failures, to improve public safety and homeland security and to promote the health and well being of the general public.

Explore further: Seeing through the fog (and dust and snow) of war

More information: Wu and Sun recently published findings on distortion-tolerant wireless networks in IEEE Transactions on Wireless Communications.

add to favorites email to friend print save as pdf

Related Stories

Imec achieves breakthrough in battery-less radios

Feb 09, 2010

At today's International Solid State Circuit Conference, Imec and Holst Centre report a 2.4GHz/915MHz wake-up receiver which consumes only 51µW power. This record low power achievement opens the door to battery-less ...

Recommended for you

Seeing through the fog (and dust and snow) of war

2 hours ago

Degraded visibility—which encompasses diverse environmental conditions including severe weather, dust kicked up during takeoff and landing and poor visual contrast among different parts of terrain—often ...

The oscillator that could makeover the mechanical watch

Sep 18, 2014

For the first time in 200 years the heart of the mechanical watch has been reinvented, thereby improving precision and autonomy while making the watch completely silent. EPFL researchers have developed an ...

User comments : 0