Selection Relay Based RF-VLC Underwater Communication System
Mohammad Furqan Ali, TharinduD. Ponnimbaduge Perera,Vladislav S. Sergeevich, Sheikh Arbid Irfan, Unzhakova Ekaterina Viktorovana, Weijia Zhang, Ândrei Campongara and Dushantha Nalin K. Jayakody
(School of Computer Science and Robotics, Tomsk Polytechnic University, RUSSIA)
(Fédéral Université of Juizde Fora, Brazil)
(School of Postgraduate Studies, Sri Lanka Technological Campus, Sri Lanka)
  • Introduction
  • Comparison of Underwater Wireless Communication Techniques
  • The necessities of Underwater Wireless Communication
  • Proposed RF-VLC system model
> Source (s) to Relay (r) RF link
> Relay (r) to Undersea based destination (d) VLC link
  • Underwater Channel Condition Modeling
> Underwater Attenuation Model
> Underwater Turbidity Channel Coefficient Model
> Pointing Error (Misalignment) Coefficient Model
  • Hybrid Underwater Communication Applications
  • Simulation and Numerical Results
  • Conclusion

  • Due to massive water reservoir as oceans, underwater signaling received a great interest to explore aqueous sectors and aquatic phenomenal activities.
  • UWC mostly allows signal propagation over long distances with specific communication techniques.
  • Acoustic, Optical and Electromagnetic waves (in RF ranges) wireless carriers widely used as communication media in underwater environment.
  • UWC enables many potential applications for early detection of natural hazardous.
  • The hybrid cooperative communication system proposed to long range communication and real-time data streaming.
  • Emerging next generation 5G or 6G networks in UWC opens new opportunities for signal transmission in underwater mediums.

Comparison of UWC
  • Sound waves widely used in underwater over 15-20 km but very low speed.
  • Acoustic signaling offers low bandwidth and data-rates with high delay.
  • Absorption, scattering, background noise, man-made and artificial noise are the main factors to influence acoustic signals.
  • RF waves used for short ranges specially in shallow water.
  • RF waves offer high data-rate and with minimal delay.
  • Permeability, Conductivity and Permittivity of the channel are the main factors to influence RF signal in underwater.
  • An alternative underwater signal propagation technique through optical waves.
  • Optical signal offers high bandwidth and data-rate with high speed of propagation over moderate distances.
  • The optical signals directly affected by absorption, scattering, CDOM and physiochemical properties of channel.

Necessities of UWC
  • For the real-time data streaming for military and scientific purposes.
  • Early detection warning of Tsunami, Earthquakes, floods, rising of oceans water level.
  • Monitoring the marine life, observing active volcanos and water pollution.
  • Exponential secure data for coastal securities.
  • Geographical undersea mapping, lost treasures and navigation purposes.
  • Very cost effective and easy to install.
  • Military Operation such as surveillance, intelligence, localization, targeting positions and tracking of nuclear, biological and chemical weapons.

Proposed RF-VLC System Model
System Model Cont…
VLC Link
Underwater environment Attenuation

Beer-Lambert law the path loss
hl(λ,L) = exp{c(λ)*L}
𝐜(λ) = 𝒂(λ) + 𝒃(λ)

Modified Beer-Lambert law including path loss and geometrical losses where Dr is denoted by aperture diameter, θF is full length of divergence angle and τ is the correction coefficient.
Numerical Results
Numerous UWC Applications
  • In RF-VLC system models, signal transmission inland base station to buoy through RF link while the signal transmission with relay to underwater based destination through VLC link.
  • The floating buoy used as relay to transmit signals to destination through VLC link.
  • The BER performance investigated at relay and destination, and compare in the dual hop cooperative communication system model in different water mediums.
  • A pointing error effect on BER RF-VLC hybrid link in different ocean water investigated.
  • Simulation results have shown that the RF-VLC link combination has the superior BER performance in higher transmitted SNR.

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