Solution to Signal Jamming of IoT devices Lies in Cave-Dwelling Fish

an eigenmannia/ Photo By Clinton & Charles Robertson via Wikimedia

A cave-dwelling fish could possibly save the IoT from a catastrophic disruption of signals as the world moves towards an era of interconnected devices, according to Colm Gorey, writing for the Silicon Republic.

In their quest to find devices that cannot be jammed by neighboring signals, researchers capitalized on the jamming avoidance response of a certain species of cave-dwelling fish in developing an innovative light-based device which moves the frequency of an emitted signal away from interference-causing signals.

The new device can help solve the scarcity of available bandwidth as a result of the continuous growth in the number of wireless devices and transmitted data that compete for space in an increasingly limited amount of available bandwidth.


The Eigenmannia species is a cave-dwelling fish that lives in total darkness. To help it survive in the dark, the Eigenmannia emits an electric field to communicate with other fish and to sense the nearby surroundings. When two fish send signals at the same frequency, the signals can interfere with or jam each other, resulting in a scrambled signal. But the Eigenmannia uses a unique neural algorithm that can adjust the frequency emitted signals so these do not clash with signals coming from other fish.

Mable Fok, leader of the research team, claimed that the neural algorithm could enable for a smarter and more dynamic way of using wireless communication systems without having to resort to cumbersome coordination protocols that allot specific sections of available bandwidth to the military or telecom carriers. It can also be used for optimal utilization by letting wireless devices automatically transfer to a frequency that does not interfere with other signals, Fok added. It would also bring down the cost of using  the wireless spectrum because telecom providers do not have to spend a lot of money to reserve available bandwidth,


eigenmannia/ Photo By Wolfram Sondermann via Flickr


The experimental device functions similarly to the Eigenmannia JAR in that it can spot if another signal poses a jamming threat and move its own signals to higher or lower frequencies. This allows the device to veer away from the jamming signal without crossing the interfering frequency which will only aggravate the jamming.

Since the device is light-based, it only needs slight adjustments for it to be used with a variety of frequencies, from the megahertz frequencies for radio and GPS and gigahertz frequencies for cell phones and radars which are ideal for IoT. Furthermore, a light-based system is faster than electronic systems in responding to a potential jamming signal.

The new device can prevent signal interference in several applications such as unintentional jamming when radars are operating in the same area. It could also be used in hospitals where wireless devices can interfere with wireless transmissions emitted by medical instruments.

To be able to realize such a device, the researchers used a semiconductor optical amplifier to imitate the Eigenmannia’s JAR. The SOA can monitor its own signal and uses it to detect a potential jamming and assess if that signal is higher or lower in frequency. It then moves its own signal away from the potential jamming signal.

Fok stated that to be able to build the photonic device, they had to understand how the neurons in Eigenmannia carry out JAR and use such knowledge in designing the device. She pointed out that since the SOA functions like a neuron, it can be used to do all the necessary tasks.


The experimental device is made up of four separate components: the Zero-crossing point detection or ZeroX unit, the Phase detection unit, the Amplitude unit, and the Logic unit, all of which use semiconductor optical amplifiers that have varying optical nonlinear properties.

The ZeroX unit identifies the positive zero-crossing points of the reference signal, which will later be used as the phase reference in the Phase detection unit. The Phase detection unit determines whether the instantaneous phase of the beat signal is leading or lagging the phase of the reference signal. It takes as inputs the zero-crossing reference, pulses output from the ZeroX unit and the beat signal between the reference signal and jamming signal.

The Amplitude unit returns a different value for the rising and falling edge in amplitude portions of the beat envelope. A positive value output indicates a rising amplitude and a negative value output means a falling amplitude. The logic unit supplies the voltage for driving the voltage-controlled oscillator that generates the initial reference frequency.

Microwave signals are then employed to jam the photonic device which responds by automatically adjusting its own signal frequency and stops when the jamming signal moves away. The device is capable of evading sinusoidal, amplitude-modulated, and digitally-modulated jamming signals.

The researchers are doing further research on the system so that it can respond to multiple jamming signals. They also plan to make the device portable and easy to use by non-technical users.