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  • Published: 09 June 2022

Underwater wireless communication via TENG-generated Maxwell’s displacement current

  • Hongfa Zhao   ORCID: orcid.org/0000-0003-1929-3184 1 , 2   na1 ,
  • Minyi Xu   ORCID: orcid.org/0000-0002-3772-8340 1   na1 ,
  • Mingrui Shu   ORCID: orcid.org/0000-0001-9139-5092 1   na1 ,
  • Jie An   ORCID: orcid.org/0000-0002-0028-0079 3 ,
  • Wenbo Ding   ORCID: orcid.org/0000-0002-0597-4512 2 ,
  • Xiangyu Liu   ORCID: orcid.org/0000-0003-0386-9089 1 ,
  • Siyuan Wang   ORCID: orcid.org/0000-0001-7174-9754 1 ,
  • Cong Zhao   ORCID: orcid.org/0000-0003-3647-7567 1 ,
  • Hongyong Yu   ORCID: orcid.org/0000-0002-7195-7139 1 ,
  • Hao Wang   ORCID: orcid.org/0000-0002-9238-9791 1 ,
  • Chuan Wang 1 ,
  • Xianping Fu   ORCID: orcid.org/0000-0001-9888-9327 1 ,
  • Xinxiang Pan   ORCID: orcid.org/0000-0003-0460-0620 1 ,
  • Guangming Xie   ORCID: orcid.org/0000-0001-6504-0087 1 , 4 , 5 &
  • Zhong Lin Wang   ORCID: orcid.org/0000-0002-5530-0380 3 , 6  

Nature Communications volume  13 , Article number:  3325 ( 2022 ) Cite this article

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  • Applied physics
  • Electrical and electronic engineering
  • Sensors and biosensors

Underwater communication is a critical and challenging issue, on account of the complex underwater environment. This study introduces an underwater wireless communication approach via Maxwell’s displacement current generated by a triboelectric nanogenerator. Underwater electric field can be generated through a wire connected to a triboelectric nanogenerator, while current signal can be inducted in an underwater receiver certain distance away. The received current signals are basically immune to disturbances from salinity, turbidity and submerged obstacles. Even after passing through a 100 m long spiral water pipe, the electric signals are not distorted in waveform. By modulating and demodulating the current signals generated by a sound driven triboelectric nanogenerator, texts and images can be transmitted in a water tank at 16 bits/s. An underwater lighting system is operated by the triboelectric nanogenerator-based voice-activated controller wirelessly. This triboelectric nanogenerator-based approach can form the basis for an alternative wireless communication in complex underwater environments.

Introduction

In the booming ocean exploration, underwater equipment and technology is attracting more and more attention 1 , 2 , 3 , 4 , 5 . Particularly, obtaining underwater wireless communication has always been a critical challenge. The current underwater communication is achieved through different physical fields, such as acoustic field, optical field, and electromagnetic field 6 , 7 , 8 .

Acoustic communication is most widely used underwater communication as sound wave is not absorbed by water so easily like electromagnetic wave and optical wave. However, acoustic communication has always been accompanied by considerable transmission delays while the transmission is subject to influences from temperature, pressure, and salinity, which leads to multipath effects and Doppler frequency shift. What’s more, echo and reverberation from obstacles could make acoustic communications inaccessible in certain environments (such as confined space, narrow pipes, tunnels, and caves) 9 , 10 . Underwater optical communication can realize large-capacity data transmission, but it is subject to absorption, scattering, beam divergence, and ambient light interruptions 11 , 12 . Compared to the acoustic and optical waves, the electromagnetic waves are not affected by acoustic noise or turbulence. Underwater displacement current communication usually has high transmission rate and low delay 10 . While high-frequency electromagnetic waves will be largely absorbed by water 13 , 14 , low-frequency electromagnetic waves can transmit through an antenna of several kilometers. In sum, complex and sometimes confined underwater space turns out to be a considerable challenge to traditional underwater communication technologies.

Under those conditions, an alternative communication that can work well in underwater space is definitely needed. An inspiration comes to our mind from the Maxwell’s equations, foundation of modern wireless electromagnetic communication. The displacement current, corresponding to ∂ D /∂ t in the Maxwell’s equations, is what unified electricity and magnetism theoratically 15 . Of the two terms in displacement current, the first term ∂ E /∂ t induces electromagnetic waves widely used in information technology, especially in wireless communications. The second term ∂ P /∂ t in the displacement current is induced by the polarization of media 16 , 17 . Previous studies by Prof. Z. L. Wang reveal that the second term ∂ P /∂ t in the Maxwell’s displacement current can be directly related to the output electric current of the nanogenerator 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 . A few studies have been performed on the energy transmission or communications (in air), based on the Maxwell’s displacement current generated by the triboelectric nanogenerator (TENG). Recently, Zi et al. (2021) used TENGs to generate a rapidly alternating electric field so that wireless communication in air can be realized by the displacement current ∂ P /∂ t 26 . Compared with air, water is of a larger dielectric constant, which is more conducive to the propagation of the polarization electric field. Therefore, based on the second term of the displacement current, i.e., the polarization electric field, underwater communication in complex waters is feasible.

In this study, an underwater wireless communication via Maxwell’s displacement current, ∂ P /∂ t , is proposed. The TENG that converts sound to electricity is connected to a transmitting electrode to generate the time-varying polarization electric field underwater. The corresponding time-varying current is measured with a receiving electrode connected to an electrometer. The study reveals that the current signals generated by the TENG yield good anti-interference ability to underwater disturbances. Through a 100 m long salt water pipe, the peak value of the current signal decreases by 66% from the original signal, while the waveforms of the electric signals are not distorted. With the on-off keying method, texts and images can be successfully transmitted in a water tank. No errors appeared in the continuous transmission for about 20,000 digital signals, and an underwater lighting system has been voice-controlled wirelessly via the TENG. What’s more, the current signals output by a sandwich-like TENG can be transmitted in a 50 m × 30 m × 5 m basin with the signals displayed on screen in real time. Therefore, it is believed that the presented work could become an effective communication approach in underwater environments.

Working principle of the underwater electric field communication

A conceptual diagram of the application of the studied underwater communication is shown in Fig.  1 . The TENG converts sound (i.e. sonic waves in air) to electric signals in water (Fig.  1a ), and the electric signals carrying the voice information can be transmitted in water and received by the diver. In this way, an underwater wireless communication is established via Maxwell’s displacement current generated by the TENG. Figure  1b is the flow chart of the underwater communication. It needs to be noted that this method is different from the electric field communication generated from a pair of electric dipoles (see Supplementary Note  1 ).

figure 1

(signals generated by TENG is directly transmitted without amplification by an external power source). a The application and ( b ) the flow chart of the underwater wireless communication. c Schematic diagram of the capacitance model, \({{{\varepsilon }}}_{{{r}}}\) is relative permittivity, E is the original electric field, P is the polarization electric field, E′ is the combined electric field of ( E ) and ( P ), and all about Q are amount of charge.

The working principle of the underwater communication can be understood, approximately, with a capacitance model (Fig.  1c ). The propagation of underwater electric field is analyzed from the perspective of displacement current. The transmitting and receiving electrodes form the positive and negative electrodes of the capacitor, while the water solution is the dielectric. With the presence of electric field E , the dielectric can be polarized where a polarization electric field P can be generated. It should be noted that the polarization electric field P is originated from the negative polarization charge to the positive polarization charge. \({{{{{\bf{E}}}}}}^{\prime}\) is the combined electric field of E and P , If the relative permittivity is defined as \({\varepsilon }_{r}={{{{{\bf{E}}}}}}{{{{{\boldsymbol{/}}}}}}{{{{{\bf{E}}}}}}^{\prime}\) , the relationship between the polarization charge and the charge Q on the transmitting electrode is \({Q}^{\prime} =(1-1/{\varepsilon }_{r})Q\) . Due to the attenuation of the electric field during through propagation medium, the received charge \(Q^{\prime\prime}\) at the receiving electrode is < \(Q^{\prime}\) .

The underwater communication can be demonstrated theoretically with the Maxwell’s equation. Remind that the Gauss’s law of the Maxwell’s equations is

where ρ is the distribution of free charges in space, and D is the electric displacement vector, which can be expressed as

where permittivity in vacuum is \({{{\varepsilon }}}_{{{0}}}\) . The Maxwell’s displacement current density can be defined as

From Eq. ( 3 ), the first term \({{{\varepsilon }}}_{{{0}}}\partial {{{{{\bf{E}}}}}}/\partial {t}\) gives rise to electromagnetic wave. Studies of Prof. Zhonglin Wang reveal that the second term (∂ P /∂t) in the Maxwell’s displacement current can be directly related to the output electric current of the TENG 15 .

It is worth mentioning that the internal circuit in the TENG is dominated by the displacement current, and the observed current in the external circuit is the capacitive conduction current (see Supplementary Note  2 ). The research on the underwater electric field propagation is inspired by the built-in electric field of the TENG. Comparing the TENG-based underwater electric field with electromagnetic waves, the propagation of electromagnetic waves does not require a medium, and the propagation effect is best in vacuum. At this time, ∂ E /∂t reaches the maximum value, and ∂ P /∂t is 0. The propagation of the polarization electric field requires a medium (see Supplementary Note  3 ). As ∂ E /∂t gets significantly reduced in water, the propagation effect of ∂ P /∂t gets improved.

To examine the performance of the underwater communication, an acoustic-driven TENG is applied to convert sound in air to electrical signals in water. The output performance of the acoustic-driven TENG has been investigated systematically in our previous study 27 . As shown in Fig.  2a , the TENG consists of a Helmholtz resonant cavity, an aluminum film with evenly distributed acoustic holes, and a fluorinated ethylene propylene (FEP) film with a conductive ink-printed electrode (details about the TENG is shown in Supplementary Notes  4 and 5 ). The transmitting electrode in water is connected to the aluminum electrode of the TENG, while the other electrode of the TENG is grounded so that the TENG operates in the single-electrode mode. In reaching an electrostatic equilibrium state, higher electrical output can be obtained by acquiring ground charges 28 . It is worth noting that one piece of conduct materials, such as metal and salt water, can serve as a charge reservoir for the TENG.

figure 2

a Schematic diagram of the experimental process. I D represents displacement current in all figures. b Schematic diagram of the working principle. E is the underwater electric field, and v is the speed of the TENG for contact and separation. c The short-circuit current signals (measured by connecting an electrometer to the aluminum electrode). d The short-circuit current signal obtained by connecting the electrometer to the receiving electrode.

Figure  2b shows the working principle of the underwater communication, which is based on the interface polarization from the Maxwell-Wagner effect. The electrical output is generated from the variation of the built-in electric field in the TENG, which is directly related to the second term (∂ P /∂t) in the Maxwell’s displacement current 15 . A transmitting electrode is connected to one electrode of the TENG, thus an electric field \({{{{{{\bf{E}}}}}}}_{{{{{{\bf{0}}}}}}}\) is induced in water as the TENG works (see Fig.  2b ). Corresponding to the variation of electric field \({{{{{{\bf{E}}}}}}}_{{{{{{\bf{0}}}}}}}\) , the positive and negative ions in the water move reciprocally, generating a polarization electric field \({{{{{{\bf{P}}}}}}}_{{{{{{\bf{0}}}}}}}\) . The current in the receiving electrode induced by the polarization electric field can be measured with an electrometer. The electric field \({{{{{{\bf{E}}}}}}}_{{{{{{\bf{0}}}}}}}\) generated by the TENG is related to the charge density \({{{{{{\boldsymbol{\rho }}}}}}}_{{{{{{\boldsymbol{0}}}}}}}\) in the transmitting electrode in the following form:

\({{{{{{\bf{P}}}}}}}_{{{{{{\bf{0}}}}}}}\) is the polarization electric field generated from the electric field \({{{{{{\bf{E}}}}}}}_{{{{{{\bf{0}}}}}}}\) , which is

Therefore, the second term \({{{{{{\bf{J}}}}}}}_{{{{{{\bf{p}}}}}}}\) in the Maxwell’s displacement current (generated by the polarization electric field) is

For the acoustic driven HR-TENG, when the FEP film contacts with the aluminum film, the electron clouds on the surfaces of the two films overlap, and some of the electrons from the aluminum film enter the deeper potential well of the FEP film. Due to the much higher electronegativity of FEP than aluminum, the free electrons on the surface of the aluminum film transfer to the lowest unoccupied molecular orbital of the FEP interface. So the aluminum film becomes positively charged (Supplementary Fig.  1a ). Since the transmitting electrode is connected to the aluminum film, positive charges are also distributed on the surface of the transmitting electrode. Negatively charged ions in the water are attracted by the transmitting electrode, while positively charged ions are repelled to the surroundings. When positive ions contact with the receiving electrode, electrons in the receiving circuit flow to the receiving electrode, so the electrometer detects a positive current. Due to the change in the acoustic pressure difference, the FEP film is separated from the aluminum electrode. At the moment, electrons flow from the ground to the conductive ink electrode to balance the electric field between the FEP film and the conductive ink electrode. Due to the negative charge distributed on the surface of the FEP film, the free electrons on the aluminum film are repelled, so the electrons flow from the aluminum film to the transmitting electrode. Opposite to before, positive charged ions in the water are attracted by the transmitting electrode, while negative charged ions are repelled to the surroundings (Supplementary Fig.  1b ). When negative ions contact with the receiving electrode, electrons in the receiving electrode flow to the receiving circuit, so the electrometer detects a negative current.

Figure  2c, d compares the electric signals in air with those in ordinary water. Under acoustic waves (80 Hz, 80 dB), the corresponding periodic output short-circuit current signals yield the peak value of 14.9 μA (Fig.  2b ), which is directly measured with the electrometer connected to the aluminum electrode. When the (electrometer-connected) receiving electrode is two meters away from the submerged transmitting electrode, the peak value of the current decreases slightly to 14.5 μA while the waveform of electric signals remain constant (Fig.  2c ). The peak value of open-circuit voltage output of the TENG decreases from 28.5 V in air to 13 V in water (see Supplementary Fig.  2 ). When the water tank is grounded by a wire, the output current decreases significantly, but the waveform of electric signals stay consistent with the original signal (Supplementary Fig.  3 ). This can be explained by the tendency that charges from ground would balance the electrical potential field in water. Furthermore, the current signal could still be measured even when the transmitting electrode is insulated from water by a Kapton tape (Supplementary Fig.  4 ), and the electric field generated by the TENG can propagate across both gas and liquid media (Supplementary Fig.  5 ). These prove that the transmission of the signals depends on the electric field radiated by the TENG rather than the direct exchange of electrons between water and electrode plates. Both theoretical analysis and experiments have shown that for the whole system, the propagation of underwater electric field has demonstrated the characteristic of displacement current (see Supplementary Note  6 ). Previous study 29 proved that when the electric field propagates in a medium, conduction current dominates when \({{{{{\boldsymbol{\sigma }}}}}}{{{{{\boldsymbol{/}}}}}}{{{{{\boldsymbol{\omega }}}}}}\; > \;{{\varepsilon }}\) and displacement current dominates when \({{\varepsilon }}\, > \,{{{{{\boldsymbol{\sigma }}}}}}{{{{{\boldsymbol{/}}}}}}{{{{{\boldsymbol{\omega }}}}}}\) (σ is conductivity, ω is angular frequency, and ε is permittivity). The Rayleigh distance of the TENG generated electric field can be calculated by \({{{{{\boldsymbol{R}}}}}}=2{{{{{{\boldsymbol{D}}}}}}}^{{{{{{\boldsymbol{2}}}}}}}{{{{{\boldsymbol{/}}}}}}{{{{{\boldsymbol{\lambda }}}}}}\) , where R is Rayleigh distance, D is the maximum size of the transmitting electrode, and λ is the wave length. As a result, R is so small that it can be neglected. According to these theories, for the TENG-based underwater electric field communication, \({{\varepsilon }}\, > \,{{{{{\boldsymbol{\sigma }}}}}}{{{{{\boldsymbol{/}}}}}}{{{{{\boldsymbol{\omega }}}}}}\) and the transmitting distance is larger than the Rayleigh distance. So the displacement current domains the underwater electric field while conduction current only appears in a very short distance.

It is worth mentioning that underwater communication can also be realized by various types of TENGs, such as the TENGs that harvest wave energy and vibration energy (see Supplementary Fig.  6 , and the first and second items in Supplementary Table  1 ). The development of the electric field communication depends on the development of TENG technology. The techniques for designing TENGs with high frequency and good output performance (see Supplementary Table  1 ) provides good potential for the application of the TENG in underwater communication 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 .

Transmission performance of the underwater electric field

The characteristics of the underwater electric field under different parameters such as water volume, electrode position/size, salinity, water turbidity, and underwater obstacles, have been studied. Figure  3 shows the attenuation of the underwater electric field. In a 3 m × 2 m × 0.4 m water tank (Fig.  3a ), the receiving electrode is placed certain distance away from the transmitting electrode. As the distance increases from 1 m to 3 m, the current signals remain almost unchanged (Fig.  3b ). This is also verified by the simulation of underwater polarization electric field shown in Supplementary Fig.  7 . Furthermore, the complete signals output by the TENG and received signals underwater, and their Fourier transforms are shown in Supplementary Figs.  8 – 9 , showing that the frequency-domain features of the signals remain unchanged underwater. As more water is added into the tank, the peak value of the current decreases. Actually, the peak value decreases by 30% from the original signals as the water volume reaches 6 m 3 (Fig.  3c ). This can be understood, as the electric field energy W in water is

According to Eq. ( 7 ), the energy density of the electric field decreases with the water volume V while using a TENG with constant power output. Therefore, the peak value of the current decreases with larger water volume.

figure 3

a A photo of the experiment. b Comparison between the original TENG short-circuit current and received current signals in water. c Comparison between the original short-circuit current of the TENG and received signals under different water volume. d Schematic diagram of the electrode. e Comparison of the current signals received in water with different transmitting and receiving electrodes. Tr, Re, and Pl represents transmitting electrode, receiving electrode, and electrode plate respectively. f Comparison of the peak values of the received current signals with different receiving electrodes. Simulation diagram of the distribution of polarization electric field ( g ) without and ( h ) with the receiving electrode. Color represents polarization intensity. i Variation of polarization electric field and charges on the receiving electrode with the distance between the two electrodes.

As shown in Fig.  3d–f , the current can be enhanced by using a receiving electrode plate of larger area. With a 10 cm × 5 cm electrode plate, the peak value of the current signal increases by 18%, compared to that with a thin electric wire. This means more ions in water contacting with the electrode, which is verified by the underwater polarization electric field simulation shown in Supplementary Fig.  10 . In addition, the peak value of the current is subject to the angle between the transmitting and receiving electrode plates, but the effect caused by the angle is very small in the water tank (see Supplementary Figs.  11 – 12 ), which is quite different from the case in a bipolar electric field 38 .

By comparing the distribution of the polarization electric fields without and with the receiving electrode (Fig.  3g, h ), it is found that the receiving electrode can change the distribution of the polarization electric field. This can be explained by the fact that the electrode is equivalent to a terminal with a potential of zero voltage. The variation of the polarization electric field and the variation of the terminal charges in the receiving electrode are shown in Fig.  3i . A 2D simulation is performed and the polarization electric field distribution corresponding to Fig.  3i is shown in Supplementary Figs.  13 and 14 . The attenuation of the polarization electric field and terminal charges at the receiving electrode with distance can be fitted respectively

k 1 , k 2 , k 3 and a are parameters in the fitted curves of the output power of the TENG (Supplementary Figs.  15 and 16 ). According to the simulation results, the exponent of x is close to −1 for two dimension simulations (Supplementary Figs.  15 and 16 ), and close to −2 for three dimension simulations (Supplementary Figs.  17 and 18 ), which is consistence with the Gauss’s law.

The dependence of the underwater electric field on disturbances in water is shown in Fig.  4 . It is found that the peak value of the current signal in salty water (5 g L −1 , adjusted by adding salt to water) increases by 40% on top of that in pure water (Fig.  4a ). This indicates that the ions in salt water can enhance the polarization electric field. However, water salinity increase beyond 15 g L −1 will not further promote the current signals. Similarly, when acid or alkali is added to the pure water to change the pH, the ion concentration in the water will change, indicating that as the pH of water deviates from 7, the received current signals will increase (Supplementary Fig.  19 ). This may be attributed to the improved relative permittivity of the aqueous solution. Figure  4b, c reveal that the waveform of the received signals identical to original ones, regardless of obstacles or turbidity in the water tank. In this sense, the polarization electric field has shown robustness to obstacles and water turbidity.

figure 4

a Effect of water salinity on the peak value of the current. Error bars indicate standard deviations, with all values ≤0.53. b Influence of an obstacle on the current signals. c Comparison between the received current signals in clean water and those in turbid water. d Schematic diagram of the drilling platform with oil pipeline. e Variation of the peak value of short-circuit current output transmitted in a water pipe of 100 meters. Tr and Re represent transmitting and receiving electrodes respectively. v is the liquid flowing speed. Error bars indicate standard deviations, with all values ≤0.46. f Comparison between the short-circuit current signals transmitted in a straight and those in a curved water pipe.

As achieving reliable communication across the pipe is very important for the pipeline robot system 39 , 40 , the performance of the polarization electric field in liquid pipes is investigated (Fig.  4d–f ). Figure  4d is a schematic diagram of the drilling platform with the oil pipeline. In a pipe filled with salt water, the peak value of the current is also found to decreases with the distance between the transmitting electrode and receiving electrode. In fact, the value decreases by 66% when the distance in-between is 100 m (Fig.  4e ), which is consistent with the simulation result of the polarization electric field in the pipe (as shown in Supplementary Fig.  20 ).

In fact, the collision between ions and water molecules may influence the performance of the electric field. In addition, it is interesting to find that the received signals in a spiral pipe are the same with those in a straight pipe (Fig.  4f ). From Supplementary Fig.  21 , it is found that independent of the flow status, the current signals can also be obtained in the mixture of oil and water, which means the polarization electric field communication can be applied in complex pipelines.

It is worth noting that the electric field communication is also insensitive to water temperature and ambient lightness (Supplementary Fig.  22 ). Further comparisons between acoustic, optical, and electromagnetic waves methods are shown in Supplementary Table  2 . What’s more, by studying the effect of the ground on the electric field, it is theoretically proved that this system may work in open water area as shown in Supplementary Note  7 .

Modulation and demodulation of the underwater electric field communication

The modulation and demodulation process of current signals for data transmission in water is shown in Fig.  5 . The current signals converted from sound waves by the TENG can be modulated to digital signals containing the information of texts or images in water via the electric field communication (Fig.  5a ). The signal modulation method is based on the on-off keying (OOK), in which longer signals with time intervals of 50 ms is set as “1”, and shorter signals with time intervals of 25 ms is set as “0”. A 25 ms interval is inserted between each digital signal to separate adjacent digital signals. After transmission in water, the modulated digital signals can be received by the electrometer (Fig.  5b ). The fundamental frequency of the signals generated by the TENG is 80 Hz, and the frequency of the modulated digital signals is 16 Hz. Alternatively, the digital signals can be modulated with other frequencies or other methods (see Supplementary Fig.  23a, b ). Higher frequency yields a fast information transmission rate, while lower frequency yields a strong anti-interference ability.

figure 5

a Schematic diagram of the modulation and demodulation process. b The modulated digital signals transmitted in water. c The demodulated current signals to a word after transmitting in water. d Part of current signals transmitted for an image.

By demodulating the received signal (with the MATLAB codes), the signals of “0” and “1” can be identified accurately (Fig.  5b and Supplementary Fig.  23c ). The current signals can be modulated into text by the standard encoding. The received signals can be accurately demodulated into the original text (Fig.  5c ). Supplementary Movie  1 shows that the real-time current signals generated by the TENG is modulated, transmitted, and demodulated, and the text obtained after demodulation is displayed on a computer screen. This electric field communication can also be used for image transmission. Figure  5d shows part of the received current signals, and the complete signals are shown in Supplementary Fig.  23d . A 2.7-KB image is transmitted within 1353 s at 16 bits/s (owing to the low fundamental frequency of the TENG). There is no error signal in the continuous transmission of ~20,000 digital signals (100,000 working cycles of the TENG). In addition, by applying an external alternating current on the dielectric material’s electrode, the electric signals with higher frequencies (up to kilohertz) can be modulated and transmitted in water, demonstrating that this approach can be used for high frequencies communication (see Supplementary Note  8 ).

It should be noted that the current signals output by the TENG and received signals underwater at a range of 60–200 Hz are compared. It turns out that the signals received underwater are always consistent in waveforms with the signals output by the TENG (see Supplementary Fig.  24 ). What’s more, the power spectrum is obtained by performing Fourier transform to the modulated digital signals and noise. The power spectrum shows that energy is evenly distributed in the frequency range from 40 kHz to 85 kHz (see Supplementary Fig.  25 ), proving that the bandwidth of the system with water channel is greater than 85 kHz.

Realization of wireless control using the underwater electric field communication

To further study the ability of the underwater wireless communication, a demo voice control of an underwater lighting system is performed (Fig.  6 ). A microphone-style TENG that converts voice to electrical signals is to control the underwater lighting system wirelessly (Fig.  6a ). The signals containing the voice information (e.g. “red” and “green”) are transmitted in water and received by the electrometer (Fig.  6b ). By performing short-time Fourier transform to the signals, the words “red” and “green” can be distinguished with a neural network algorithm (see Fig.  6c and Supplementary Fig.  26 ). Subsequently, the words are converted into digital signals to control the lights. This approach can be applied in the real-time voice control of underwater lights (Fig.  6d and Supplementary Movie  2 ). It is worth mentioning that the entire underwater communication realized by the TENG is self-powered.

figure 6

a The schematic diagram of underwater light wirelessly controlled by voice. b The received signals of “red” and “green”. c The short-time Fourier transform of “red” and “green”. Colors represent amplitudes. d The photo of the voice control experiment setup. e The experiment of the button-type TENG controlling an independent system. f The photo of the touch control experiment. g The schematic diagram and ( h ) The photo of the experiment in a 50 m × 30 m × 5 m basin. D is the distance between two electrodes. i The received current signals underwater.

At the same time, the signals receiving and controlling device in the water can be designed independently. By touching a (contact-separation mode) button-type TENG, people can use the electric to control the independent working system in water (see Fig.  6e, f and Supplementary Movie  3 ). The independent working system consists of a weak current acquisition board, a single-chip microcomputer, batteries, a relay, and an underwater working light. The pulse signals generated by the TENG are collected by the weak current acquisition board, and the analog signals are converted into digital signals sent to the microcontroller. The single-chip microcomputer processed the digital signals and controlled the underwater working light.

In another demo experiment, a sandwich-like TENG (S-TENG) with an output current of 60 μA is deployed in a 50 m × 30 m × 5 m basin (with all boundaries connected to the ground, see Fig.  6g, h . When the S-TENG is shaken, the current signals outputted by the S-TENG can be transmitted in water and received by the receiving electrode 5 m away from the transmitting electrode. The signals are detected by a current acquisition board (Supplementary Note  9 ), which sends the signals to a computer through WiFi and then the waveforms are displayed on the screen (Fig.  6i and Supplementary Movie  4 ).

In summary, an underwater communication via Maxwell’s displacement current is proposed and investigated. In the Maxwell’s displacement current, the first term ∂ E /∂ t gives rise to electromagnetic waves. However, in underwater environments, the high-frequency electromagnetic waves can be easily absorbed, and the low-frequency electromagnetic waves can only be transmitted through an antenna of several kilometers. In this study, the second term (∂ P /∂ t ) in the Maxwell’s displacement current is utilized for underwater communication. An acoustic-driven TENG connected to a transmitting electrode is applied to generate alternating electric field in water, so that the sound in air can be converted into underwater electrical signals, which can be measured with a receiving electrode connected to an electrometer. Through a salt water pipe of 100 m length, the peak value of the current signal decreases by 66% compared to the original signal, while the electric signals are not distorted in waveform during transmission.

Based on the on-off keying method, texts and images have been successfully transmitted by modulated current signals in a water tank at 16 bits/s. Throughout the continuous transmission of about 20,000 digital signals, no error appears. By successfully converting voices into current signals, the TENG is capable of controlling an underwater lighting system wirelessly. What’s more, the current signals output by a sandwich-like TENG can be transmitted in a 50 m × 30 m × 5 m basin with the signals displayed on screen in real time. Compared to traditional sonic, optical, and electromagnetic communications, the underwater communication via Maxwell’s displacement current appears to be less vulnerable to disturbances, which exhibits considerable potential for applications in complex underwater environments.

Fabrication of the TENGs

The HR-TENG in the experiments consists of a Helmholtz resonant cavity, an aluminum film with acoustic holes, and an FEP film with a conductive ink-printed electrode. The resonant cavity has a dimension of 73 mm × 73 mm × 40 mm. Two tubes with an inner diameter of 5.0 mm and a length of 32 mm are fixed on the resonant cavity. The aluminum film with 440 uniformly distributed acoustic holes acts as the electropositive triboelectric layer. The length, width, and thickness of the film are 45 mm, 45 mm, and 0.1 mm, respectively and the diameter of the holes is 0.5 mm. The FEP film is used as the electronegative triboelectric layer on observation of its strong electronegativity and good flexibility. It has a thickness of 12.5 μm and a working area of 45 mm × 45 mm. Given that the FEP material is insulated, a conductive ink electrode with a micron thickness is attached to the other side of the FEP film to transfer electrons. A screen printing device (Tou) is used to print the conductive ink (CH-8(MOD2)) on the FEP film (WitLan). The shell is printed by a 3D printer with PLA material.

The TENG to recognize voice is similar to the HR-TENG, except that it has no dule-tube structure but has a 45 mm × 45 mm opening on one side of the resonance cavity. The contact separation distance between the FEP and aluminum film is ~0.2 mm. The membrane structure of the button-type TENG is the same as HR-TENG without a cavity.

The acrylic plate of a single layer S-TENG is of 5 mm thickness and 10 cm diameter. Two aluminum electrodes with a thickness of 50 µm and an area of 6 cm × 4 cm are parallel attached onto two sides of the acrylic plate. PTFE balls with 10.5 mm diameter are filled between two acrylic plates and they are produced by 3 M company. Each S-TENG unit consists of 10 layers stacked S-TENG in parallel connection and acrylic block shell. The acrylic block shell has 10 cm diameter and 20 cm height. There are four AC output copper ends in an S-TENG unit, one pair at the top and the other pair at the bottom. The buoy consists of 5 S-TENG units as the power module and an acrylic shell as the frame structure. The S- TENG units integrated inside are in parallel connection to make the AC electrical output in-phase and the they are fixed through packing tape.

Experimental process and measuring equipment

The output signals are measured with a Keithley 6514 electrometer. The HR-TENG is mounted on an optical plate with a loudspeaker (JBL), driven by sinusoidal waves from a function generator (YE1311). One electrode of the TENG is grounded and the other electrode is immersed in water. The wires used for electrodes has a 0.3 mm copper core, and the electrode plates are copper films with the size of 100 × 50 × 0.06 mm. The water pipe used in the experiment is an ordinary PVC rubber water pipe with an inner diameter of 13 mm. A 12 V DC motor is used to control the flow of liquid in the pipe. The signal modulator consists of a microcontroller development board (STM32F7) and a relay. The MATLAB interface in LABVIEW is used to demodulate and display the real-time signals measured with the electrometer. The signals generated by the voice-driven TENG need to be filtered at 50 Hz and its harmonics after being received.

The transmitting electrode in water and the aluminum electrode of the TENG is connected by an ordinary copper wire. The HR-TENG is applied to convert sound in air to electrical signals in water. In this way, acoustic waves with specific frequencies can be got by controlling the signal generator and a loudspeaker. Furthermore, under the excitation of the acoustic waves, electrical signals with specific frequencies can be generated by the HR-TENG to examine the performance of the underwater communication. Button type TENG is a basic and commonly used TENG with the simplest structure. The application of the button type TENG prove that underwater communication can be realized by general TENGs, demonstrating the application potential of this approach.

Numerical simulations

In order to verify the accuracy of the derived theory and experimental results, COMSOL Multiphysics software has been used for numerical simulations. The AD/DC modules, electrostatic interfaces, and transient state analysis are used in simulations. The distribution of the polarization electric field and terminal charge of the receiving electrode has been simulated. As the element size influences the calculation results, the ultra-fineness meshing option has been adopted in the simulation. For 3-D simulations, the size of the model is limited to 15 m. The 2-D simulation is used to analyze the attenuation of the electric field through longer distance. The error of the 3D simulation depends on the mesh size and model scale.

Data availability

The data supporting this study are available within the article and the  Supporting Information .  Source data are provided with this paper.

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Acknowledgements

The authors are grateful for the joint support from the National Key R & D Project from Minister of Science and Technology (2021YFA1201600, Z.L.W.), the National Natural Science Foundation of China (Grant Nos. 51879022, 51979045, M.Y.X.), the Fundamental Research Funds for the Central Universities, China (Grant No. 3132019330, M.Y.X.), and Tsinghua-Foshan Innovation Special Fund (TFISF, Grant No. 2020THFS0109, W.B.D.).

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These authors contributed equally: Hongfa Zhao, Minyi Xu, Mingrui Shu.

Authors and Affiliations

Marine Engineering College, Dalian Maritime University, 116026, Dalian, China

Hongfa Zhao, Minyi Xu, Mingrui Shu, Xiangyu Liu, Siyuan Wang, Cong Zhao, Hongyong Yu, Hao Wang, Chuan Wang, Xianping Fu, Xinxiang Pan & Guangming Xie

Tsinghua-Berkeley Shenzhen Institute, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, China

Hongfa Zhao & Wenbo Ding

Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, 100085, Beijing, China

Jie An & Zhong Lin Wang

Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, P. R. China

Guangming Xie

College of Engineering, Peking University, Beijing, 100871, P.R. China

School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA

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Contributions

M.X., Z.L.W., and G.X. supervised and guided the project; H.Z., M.X., M.S., and H.W. conceived the idea and designed the experiment. H.Z., J.A., C.Z., S.W., and H.Y. fabricated the devices and performed the experiments; H.Z., X.L., and C.W. did the theoretical calculation; H.Z, W.D., X.F., and X.P. discussed the experiment and results; H.W., M.X., and H.Z. wrote the manuscript. All authors discussed and reviewed the manuscript.

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Correspondence to Minyi Xu , Guangming Xie or Zhong Lin Wang .

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Zhao, H., Xu, M., Shu, M. et al. Underwater wireless communication via TENG-generated Maxwell’s displacement current. Nat Commun 13 , 3325 (2022). https://doi.org/10.1038/s41467-022-31042-8

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Device offers long-distance, low-power underwater communication

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Eight piezoelectric transducers look like toilet paper rolls and are attached to poles, near water.

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MIT researchers have demonstrated the first system for ultra-low-power underwater networking and communication, which can transmit signals across kilometer-scale distances.

This technique, which the researchers began developing several years ago, uses about one-millionth the power that existing underwater communication methods use. By expanding their battery-free system’s communication range, the researchers have made the technology more feasible for applications such as aquaculture, coastal hurricane prediction, and climate change modeling.

“What started as a very exciting intellectual idea a few years ago — underwater communication with a million times lower power — is now practical and realistic. There are still a few interesting technical challenges to address, but there is a clear path from where we are now to deployment,” says Fadel Adib, associate professor in the Department of Electrical Engineering and Computer Science and director of the Signal Kinetics group in the MIT Media Lab.

Underwater backscatter enables low-power communication by encoding data in sound waves that it reflects, or scatters, back toward a receiver. These innovations enable reflected signals to be more precisely directed at their source.

Due to this “retrodirectivity,” less signal scatters in the wrong directions, allowing for more efficient and longer-range communication.

When tested in a river and an ocean, the retrodirective device exhibited a communication range that was more than 15 times farther than previous devices. However, the experiments were limited by the length of the docks available to the researchers.

To better understand the limits of underwater backscatter, the team also developed an analytical model to predict the technology’s maximum range. The model, which they validated using experimental data, showed that their retrodirective system could communicate across kilometer-scale distances.

The researchers shared these findings in two papers which will be presented at this year’s ACM SIGCOMM and MobiCom conferences. Adib, senior author on both papers, is joined on the SIGCOMM paper by co-lead authors Aline Eid, a former postdoc who is now an assistant professor at the University of Michigan, and Jack Rademacher, a research assistant; as well as research assistants Waleed Akbar and Purui Wang, and postdoc Ahmed Allam. The MobiCom paper is also written by co-lead authors Akbar and Allam.

Communicating with sound waves

Underwater backscatter communication devices utilize an array of nodes made from “piezoelectric” materials to receive and reflect sound waves. These materials produce an electric signal when mechanical force is applied to them.

When sound waves strike the nodes, they vibrate and convert the mechanical energy to an electric charge. The nodes use that charge to scatter some of the acoustic energy back to the source, transmitting data that a receiver decodes based on the sequence of reflections.

But because the backscattered signal travels in all directions, only a small fraction reaches the source, reducing the signal strength and limiting the communication range.

To overcome this challenge, the researchers leveraged a 70-year-old radio device called a Van Atta array, in which symmetric pairs of antennas are connected in such a way that the array reflects energy back in the direction it came from.

But connecting piezoelectric nodes to make a Van Atta array reduces their efficiency. The researchers avoided this problem by placing a transformer between pairs of connected nodes. The transformer, which transfers electric energy from one circuit to another, allows the nodes to reflect the maximum amount of energy back to the source.

“Both nodes are receiving and both nodes are reflecting, so it is a very interesting system. As you increase the number of elements in that system, you build an array that allows you to achieve much longer communication ranges,” Eid explains.

In addition, they used a technique called cross-polarity switching to encode binary data in the reflected signal. Each node has a positive and a negative terminal (like a car battery), so when the positive terminals of two nodes are connected and the negative terminals of two nodes are connected, that reflected signal is a “bit one.”

But if the researchers switch the polarity, and the negative and positive terminals are connected to each other instead, then the reflection is a “bit zero.”

“Just connecting the piezoelectric nodes together is not enough. By alternating the polarities between the two nodes, we are able to transmit data back to the remote receiver,” Rademacher explains.

When building the Van Atta array, the researchers found that if the connected nodes were too close, they would block each other’s signals. They devised a new design with staggered nodes that enables signals to reach the array from any direction. With this scalable design, the more nodes an array has, the greater its communication range.

They tested the array in more than 1,500 experimental trials in the Charles River in Cambridge, Massachusetts, and in the Atlantic Ocean, off the coast of Falmouth, Massachusetts, in collaboration with the Woods Hole Oceanographic Institution. The device achieved communication ranges of 300 meters, more than 15 times longer than they previously demonstrated.

However, they had to cut the experiments short because they ran out of space on the dock.

Modeling the maximum

That inspired the researchers to build an analytical model to determine the theoretical and practical communication limits of this new underwater backscatter technology.

Building off their group’s work on RFIDs, the team carefully crafted a model that captured the impact of system parameters, like the size of the piezoelectric nodes and the input power of the signal, on the underwater operation range of the device.

“It is not a traditional communication technology, so you need to understand how you can quantify the reflection. What are the roles of the different components in that process?” Akbar says.

For instance, the researchers needed to derive a function that captures the amount of signal reflected out of an underwater piezoelectric node with a specific size, which was among the biggest challenges of developing the model, he adds.

They used these insights to create a plug-and-play model into a which a user could enter information like input power and piezoelectric node dimensions and receive an output that shows the expected range of the system.

They evaluated the model on data from their experimental trials and found that it could accurately predict the range of retrodirected acoustic signals with an average error of less than one decibel.

Using this model, they showed that an underwater backscatter array can potentially achieve kilometer-long communication ranges.

“We are creating a new ocean technology and propelling it into the realm of the things we have been doing for 6G cellular networks. For us, it is very rewarding because we are starting to see this now very close to reality,” Adib says.

The researchers plan to continue studying underwater backscatter Van Atta arrays, perhaps using boats so they could evaluate longer communication ranges. Along the way, they intend to release tools and datasets so other researchers can build on their work. At the same time, they are beginning to move toward commercialization of this technology.

“Limited range has been an open problem in underwater backscatter networks, preventing them from being used in real-world applications. This paper takes a significant step forward in the future of underwater communication, by enabling them to operate on minimum energy while achieving long range,” says Omid Abari, assistant professor of computer science at the University of California at Los Angeles, who was not involved with this work. “The paper is the first to bring Van Atta Reflector array technique into underwater backscatter settings and demonstrate its benefits in improving the communication range by orders of magnitude. This can take battery-free underwater communication one step closer to reality, enabling applications such as underwater climate change monitoring and coastal monitoring.”

This research was funded, in part, by the Office of Naval Research, the Sloan Research Fellowship, the National Science Foundation, the MIT Media Lab, and the Doherty Chair in Ocean Utilization.

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MIT researchers have developed a new underwater system that could enable long-range and low-power underwater communication, reports Edd Gent for IEEE Spectrum . “The reason why this is really exciting is because now you start opening up many of the coastal monitoring applications,” says Prof. Fadel Adib. “It’s a turning point from this being a technology that is intellectually super interesting that we hope will work, to saying we know that this works and we have a path to deployment.”

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Popular Science reporter Andrew Paul writes that MIT researchers have developed a new long-range, low-power underwater communication system. Installing underwater communication networks “could help continuously measure a variety of oceanic datasets such as pressure, CO2, and temperature to refine climate change modeling,” writes Paul, “as well as analyze the efficacy of certain carbon capture technologies.”

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Diving deeper into our oceans: Underwater drones open new doors for global coral reef research

At the Okinawa Institute of Science and Technology (OIST), scientists at the Marine Genomics Unit, in collaboration with the Japanese telecommunications company NTT Communications, have identified the genera of mesophotic corals using eDNA collected by underwater drones for the first time. Their groundbreaking research has been published in the journal Royal Society Open Science . Now, with the help of submersible robots, large-scale eDNA monitoring of corals can be conducted without relying on direct observations during scientific scuba diving or snorkeling.

Mesophotic ('middle-light') coral ecosystems are light dependent tropical or subtropical habitats found at depths of 30 to 150 meters. They are unique because they host more native species compared to shallow-water coral ecosystems. Despite this, they are largely unexplored, and more research is needed to understand their basic biology.

Researchers studying corals access these invertebrate reef builders by snorkeling and scuba diving, but these methods have limitations, especially when identifying corals at deeper depths. Using genetic material that organisms shed from their bodies into their environment -- environmental DNA or eDNA -- scientists can identify types of corals and other organisms living in a particular habitat, providing a powerful tool for biodiversity assessment.

Importantly, studying the eDNA of corals offers unique advantages. First, unlike fish, corals are stationary, eliminating uncertainties about their location. Second, they constantly secrete mucus into the sea, providing plenty of coral eDNA for sampling. For this study, the researchers analyzed mitochondrial DNA, which is more abundant and of higher quality compared to nuclear DNA, improving the accuracy of their findings. To learn more about the coral eDNA metabarcording analysis methods used in this study, see here.

Faster and easier monitoring of coral reefs

Mesophotic coral ecosystems (MCEs) in Japan have some of the highest diversity of stony corals ( Scleractinia ) in the world, making them particularly important for researchers, but difficult to monitor because they are often located at deeper depths. Additionally, to accurately monitor corals, scientists require both scuba diving and taxonomy skills, which can be challenging. Existing methods for monitoring MCEs therefore impose limitations on conducting thorough surveys, and new methods are needed.

In October 2022, Prof. Noriyuki Satoh, leader of the Marine Genomics Unit, was approached by Mr. Shinichiro Nagahama of NTT Communications who had read about his research on coral eDNA methods. Mr. Nagahama suggested using their underwater drones to collect samples from deeper coral reefs for eDNA analysis. Prof. Satoh then put forward the idea of using the drones to conduct extensive surveys of mesophotic corals at greater depths.

Kerama National Park in Japan, about 30 km west of Okinawa Island, boasts some of the most transparent water in the Okinawa Archipelago. Often referred to as 'Kerama blue', these waters provided an excellent opportunity for the researchers to test this new sampling technique. They collected seawater samples -- each measuring 0.5 liters -- from 1 to 2 meters above the coral reefs (between 20 and 80 meters deep). The sampling sites were chosen across 24 locations within 6 different areas around the picturesque Zamami Island. The next step involved subjecting these samples to coral metabarcoding analyses, which uses Scleractinian -specific genetic markers to identify the different genera of corals present in each sample.

From the eDNA analysis results, the researchers successfully identified corals at the genus level. The presence and absence of certain genera of stony corals shown by this method indicated that reefs around the Kerama Islands exhibited different compositions of stony corals depending on location and depth. For example, the genus Acropora had the highest ratios at 11 sites, indicating that these corals are common at Zamami Island reefs. The researchers also found that the proportion of Acropora eDNA was higher at shallow reefs and upper ridges of slopes, while the proportion of the genus Porites increased at mesophotic sites. Regarding depth, Acropora was readily detected at shallow reefs (≤15 meters), while other genera were more frequently found at deeper reefs (>20 meters).

To study corals using eDNA metabarcoding methods, further sequencing of mitochondrial genomes of stony corals is needed, and this study suggests that it may be possible to more efficiently monitor mesophotic corals at the generic level using eDNA collected by underwater drones.

Collaborative innovation ahead

NTT Communications has developed a new version of the original drone used for this study. In response to a request from Prof. Satoh, an additional sampler was added so that two samples can be collected during a single dive. Additionally, the cable length between the controller and drone was extended from 150 meters to 300 meters and the battery is now changeable, so researchers can continue their survey work for an entire day.

Prof. Satoh is now working with two mesophotic coral specialists at the University of the Ryukyus, Dr. Frederick Singer and Dr. Saki Harii, to further test this method at study sites near Sesoko Island, using the new and improved drones. He hopes to revolutionize the way coral surveys are conducted. Currently, surveys are limited to very restricted spots, but with the help of these advanced underwater drones, scientists can extend their research from the shallowest regions to depths of 60 meters and beyond. "My ideal survey would include the entire spectrum of the coral reef, from the shallow waters to the mesophotic zones, and even the sandy depths. These machines provide an excellent method for conducting broader eDNA monitoring studies," he remarked.

  • Marine Biology
  • Ecology Research
  • Civil Engineering
  • Coral Reefs
  • Environmental Awareness
  • DNA microarray
  • Coral bleaching
  • Genetically modified organism
  • Veterinary medicine

Story Source:

Materials provided by Okinawa Institute of Science and Technology (OIST) Graduate University . Original written by Merle Naidoo. Note: Content may be edited for style and length.

Journal Reference :

  • Koki Nishitsuji, Shinichiro Nagahama, Haruhi Narisoko, Kazuo Shimada, Nobuhiro Okada, Yuki Shimizu, Noriyuki Satoh. Possible monitoring of mesophotic scleractinian corals using an underwater mini-ROV to sample coral eDNA . Royal Society Open Science , 2024; 11 (2) DOI: 10.1098/rsos.221586

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IMAGES

  1. (PDF) A Review of Underwater Communication Systems

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  2. (PDF) Modeling Underwater Communication Links

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  3. RELEVANCE OF UNDERWATER COMMUNICATION

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VIDEO

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COMMENTS

  1. (PDF) Underwater Communications: Recent Advances

    In this regard, underwater wireless communication (UWC) has become a significant field. Optical, acoustic and electromagnetic waves have been widely used for data transmission in UWC....

  2. Recent progress in and perspectives of underwater ...

    1. Introduction 1.1. Overview of typical underwater wireless communication techniques The collection and development of marine resources are almost inseparable from underwater communication. Therefore, the research on underwater communication technology is attracting emerging attention.

  3. Underwater wireless communication via TENG-generated Maxwell's

    6 Altmetric Metrics Abstract Underwater communication is a critical and challenging issue, on account of the complex underwater environment. This study introduces an underwater wireless...

  4. Device offers long-distance, low-power underwater communication

    "The paper is the first to bring Van Atta Reflector array technique into underwater backscatter settings and demonstrate its benefits in improving the communication range by orders of magnitude. This can take battery-free underwater communication one step closer to reality, enabling applications such as underwater climate change monitoring ...

  5. Underwater Wireless Communications: Recent Advances and Challenges

    Published Papers A special issue of Journal of Marine Science and Engineering (ISSN 2077-1312). This special issue belongs to the section "Ocean Engineering". Deadline for manuscript submissions: 25 May 2024 | Viewed by 12353 Share This Special Issue Special Issue Editors Prof. Dr. Hongxi Yin E-Mail Website Guest Editor

  6. Recent Advances and Future Directions on Underwater Wireless ...

    Underwater wireless communication (UWC) plays a significant role in observation of marine life, water pollution, oil and gas rig exploration, surveillance of natural disasters, naval tactical operations for coastal securities and to observe the changes in the underwater environment.

  7. Communication for Underwater Robots: Recent Trends

    This survey paper analyzes recent literature on underwater robotics communication, a fundamental enabler for scaling up exploration and intervention with multiple robots [15, 16].First, we provide a brief historical overview of underwater communication; then, we present recent trends of related research together with open problems and future directions.

  8. Special Issue: Underwater Communications and Sensors Technologies

    Special Issue: Underwater Communications and Sensors Technologies Editorial Published: 07 January 2021 Volume 116 , pages 955-961, ( 2021 ) Cite this article Download PDF Wireless Personal Communications Aims and scope Pablo Otero, Bhawani Shankar Chowdhry, Huacheng Zeng & Muhammad Aamir 2005 Accesses 3 Citations Explore all metrics

  9. JMSE

    Oceans cover more than 70% of the Earth's surface. For various reasons, almost 95% of these areas remain unexplored. Underwater wireless communication (UWC) has widespread applications, including real-time aquatic data collection, naval surveillance, natural disaster prevention, archaeological expeditions, oil and gas exploration, shipwreck exploration, maritime security, and the monitoring ...

  10. Design and deployment of IoT based underwater wireless communication

    High-speed underwater Wi-Fi optical communication (UWOC). In this an underwater Wi-Fi optical conversation (UWOC) device was proposed and efficiently demonstrated, based primarily on a micro-LED of 40 μm GaN. Maalox and Chlorophyll were analysed and the effects of the process brought water under sea salt [8]. Their measurements were based on ...

  11. Devices offers long-distance, low-power underwater communication

    Science News from research organizations Devices offers long-distance, low-power underwater communication The system could be used for battery-free underwater communication across...

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    Abstract: The widespread adoption of underwater wireless communications (UWC) has become an important research area to address a variety of military and commercial applications, and there is growing interest in investigating underwater environments in numerous applications.

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    This paper introduces a new attack that proves as an intruder for the whole networks. This attack is termed as antidrone cyberattacks for target systems. ... This work has an overview of possible underwater communication techniques and latest updates. ... The main outline of this chapter was to encourage research efforts and development of new ...

  14. Review Article: Underwater Voice Communication

    Abstract: In the past few decades, need and thus interest in underwater voice communication research is growing due to its application in submarines, deep water manned submersibles, and diver's communication. Compared to the initial Acoustic telephones, performance of the present systems is improved due to the continuous research interest.

  15. Underwater Wireless Communications: Recent Advances and Challenges

    Therefore, this journal aims to present the latest research results, progress and reviews in the field of underwater communication and networks, and to provide new ideas and new technologies to further promote the research and development of underwater information networks. The scope of this Special Issue includes, but is not limited to:

  16. Overview of Underwater Communication Technology

    1.2 Optical Channel. In underwater environment, optical channel can be used for short range communication. It provides higher data rate and better bandwidth as compared to the acoustic technology. Therefore, in the case of short-range communication, this technology can replace the acoustic channel.

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  18. Underwater Wireless Communications : Current Achievements and Research

    Together with sensor technology and vehicular technology, wireless communications will enable new applications ranging from environmental monitoring to gathering of oceanographic data, marine archaeology, and search and rescue missions. While wireless communication technology today has become part of our daily life, the idea of wireless undersea communications may still seem far-fetched ...

  19. Research on Underwater Bionic Covert Communication

    Covert underwater acoustic communication is the concept of stealth communication in an underwater acoustic environment. There are two main methods for realizing subtle underwater acoustic communication, including low signal-to-noise ratio (SNR) hidden communication technology and bionic hidden communication technology [ 6 ].

  20. Diving deeper into our oceans: Underwater drones open new doors for

    In October 2022, Prof. Noriyuki Satoh, leader of the Marine Genomics Unit, was approached by Shinichiro Nagahama of NTT Communications who had read about his research on coral eDNA methods.

  21. Diving deeper into our oceans: Underwater drones open new doors for

    Diving deeper into our oceans: Underwater drones open new doors for global coral reef research. ScienceDaily . Retrieved February 17, 2024 from www.sciencedaily.com / releases / 2024 / 02 ...

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