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.
“Ultralow power consumption is one of the most formidable challenges faced
by the next generation of wireless sensing systems,” says Jingxian Wu,
assistant professor of electrical engineering. “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 communication devices are powered by batteries or
energy harvesting devices such as solar panels. The lower the power consumption,
the longer the device can operate without recharging. This is especially
important for wireless sensor networks, 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 human intervention.
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 says. “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
ultralow power wireless networks. 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
The researchers’ work will accelerate the widespread deployment of ultralow
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.
The National Science Foundation grant totals $279,425 over three years.
Wu and Sun recently published findings on distortion-tolerant wireless
networks in IEEE Transactions on Wireless Communications.
Source: University of Arkansas