Even though wireless Internet at lightening speed is all around us, there is still at least one place that it moves at a snail’s pace. University of Missouri-Rolla researcher Dr. Rosa Zheng has worked since last October to create technology that speedsup wireless underwater communications.
Zheng is collaborating with Dr. Chengshan Xiao, who recently tranferred from the University of Missouri-Columbia to UM-Rolla.
Researchers that use sensors to monitor a variety of oceanic activity usually have to lay a cable to transmit information. The development of wireless would allow researchers to reach places in which they can’t lay a cable. It also would allow submarines to send data.
“The problem is once you get data, how do you reliably transmit it wirelessly to a base?” Zheng said. “When you transmit memory to a dish, it could be months later until you find out that something is wrong, and it is way too late to adjust the settings.”
Zheng is using the same acoustic waves that dolphins and whales use to communicate. She is using ultrasound band waves to transmit the information to a receiver. She has found a way to transmit data from a single transmitter to multiple receivers at 50 KB, which is 10 times higher than the previous underwater wireless speed. In comparison, 54 KB is the speed of a dial-up telephone modem.
Zheng started by studying microphone rays for wireless sound communication on land. Because there are so many ways wireless signals are transmitted on land, she decided there is more room for development underwater. She decided that she would rather work on using multiple transmiters and multiple receivers working in parallel to boost the data rate.
One of the main concerns of this research is that it will create more sound pollution underwater. Zheng said sonar waves and noises from ships create the most noise, and her sound waves “are very quiet in comparison.”
Another challenge of the research is that sound waves echo when they bounce on the surface or bottom of the ocean. Zheng said one signal can be copied up to 600 times.
“Our goal is not to throw the echoes away,” she said. “We are trying to add echoes back to the original signal to equalize it.”
Receivers need to be able to decipher the order signals were sent because they come in scrambled depending on how many times they echo, Zheng said.
When Zheng needs to test the technologies she develops, she sends them to the coasts to be tested on ships. In October, Zheng will send an experiment to Boston to see if the technology they have developed that will allow multiple transmiters to send data to multiple receivers.
“Hopefully, the weather will be bad to test the equipment under rough conditions,” she said.
Zheng’s research is funded under a three-year, $270,000 award from the Office of Naval Research.