Biomimetic Photonics Avoids Jamming Signals

Illustration of a light-based device that mimics the jamming avoidance response of Eigenmannia fish. These fish emit an electrical field for sensing and communication and use a jamming avoidance response system to move the frequency of their signal away from other signals that could potentially cause interference. (Source: W. Kirk / M. P. Fok, Univ. of Georgia)

For the first time, researchers have demon­strated a light-based device that mimics a fish’s incre­dible jamming avoidance response (JAR) by moving the frequency of an emitted signal away from other signals that could poten­tially cause inter­ference. The new system could even­tually help overcome the spectral bandwidth crunch caused by ever increa­sing numbers of wireless devices and trans­mitted data competing for space on a limited amount of available band­width.

Eigen­mannia are cave-dwelling fish that live in complete darkness. To survive without the presence of light, the fish emit an electric field to communi­cate with other fish and to sense the sur­rounding environ­ment. When two fish emit signals at similar frequencies they can interfere with each other, or jam, creating a scrambled signal. Thanks to a unique neural algo­rithm, these fish can adjust their electric communi­cation signals so that they don’t inter­fere with those coming from other nearby fish.

“We think that humans could use the same jamming avoi­dance response neural algorithm as the Eigen­mannia, but at a much faster speed and frequency,” said research team leader Mable P. Fok from the Univer­sity of Georgia. “This could allow a smarter and more dynamic way to use our wireless communication systems without the need for the compli­cated coor­dination processes that cur­rently prevent jamming by reserving whole sections of band­width for specific phone carriers or users such as the military.”

Now, the researchers demon­strated a photonic JAR that can be used to avoid jamming. They showed that the system performs much like the Eigen­mannia’s JAR in that it detects whether another signal could present a jamming problem and then intel­ligently shifts its emitting signal higher or lower in frequency so that it moves away from the jamming signal without crossing its frequency, which would amplify the jamming. Because the jamming avoi­dance system is light-based, only slight adjust­ments are needed to use it with a wide range of frequen­cies: from the mega­hertz fre­quencies used for radio and GPS communi­cation to the gigahertz signals used by cell phones and radars. Using a light-based device also allows faster automatic response to a potential jamming signal than an elec­tronic system could ac­complish.

The new techno­logy could help with signal inter­ference in several areas. For example, it could be used to avoid uninten­tional jamming when radars aboard planes or military vehicles are operating in the same area. It could also be used in environ­ments such as hospitals where wireless devices can inter­fere with wireless trans­missions coming from medical instru­ments. “Even­tually, this approach could be used to achieve effec­tive use of the wireless spectrum by allowing wireless devices to automa­tically move to a frequency that doesn’t inter­fere with other signals nearby,” said Fok. “This could bring down the cost of using the wire­less spectrum because service providers would not have to pay to reserve large amounts of band­width. This, in turn, could make it more affor­dable to bring mobile tech­nology to deve­loping countries, where it could be used to support impor­tant services such as tele­medicine or distance learning.”

The new photonic JAR system uses an off-the-shelf optical component known as a semi­conductor optical amplifier (SOA) to mimic the Eigen­mannia’s JAR. The SOA identi­fies the proper­ties of its own emitted signal and uses that as a reference to detect a potential jamming and to determine if that signal is higher or lower in frequency. It then moves the emitted signal away from the potential jamming signal. “To create the photonic system, we had to under­stand how neurons in Eigen­mannia carry out the JAR and then trans­late that from an engi­neering viewpoint into a photonic design,” said Fok. “Because the SOA actually acts very much like a neuron it could be used to do all the necessary tasks.”

The researchers tested their photonic JAR using various types of jamming signals in the micro­wave region of the electro­magnetic spectrum, which is used for local area wireless networks such as Bluetooth. “We could see the photonic JAR system move the signal frequency when a jamming signal was approaching and stop moving if the jamming frequency was moving away,” said Fok. “It happened auto­matically, almost as if it were alive.” The researchers are now working to improve the system so that it can respond to more than one jamming signal nearby. They also want to make the system portable and more user friendly for non-technical users. (Source: OSA)

Reference: R. Lin et al.: Biomimetic photonics: jamming avoidance system in Eigenmannia, Opt. Exp. 26, 13349 (2018); 10.1364/OE.26.013349

Link: Lightwave and Microwave Photonics Laboratory, College of Engineering, University of Georgia, Athens, USA


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