• Getting Started with basic concepts of Under water visible light communication.

> Why under water visible light communication MIMO systems ?

Visible Light Communication (VLC) is an emerging technology that intends to enable high speed communication links primarily in indoor environments and works on the principle of intensity modulation of solid-state lighting infrastructures provided by light-emitting diodes (LEDs). Visible Light Communication systems offer several key advantages over traditional radio-frequency based communication networks including over 300 THz of license-free bandwidth on visible wavelengths which is enormously larger than that available in radio and since VLC consumes very less amounts of power, the VLC system is a power efficient system. Underwater wireless communication is expected to play an important role in investigation of climate change, monitoring biological, biogeochemical, evolutionary, and ecological processes in sea,ocean, and lake environments, in unmanned underwater vehicles which are used to controland maintain oil production facilities and harbors, submarines, ships, divers and buoys.

> How under water visible light communication is done ?

Basically there are 3 possible methods for underwater wireless communication.

1. Radio frequency (RF) communication

2. Acoustic communication

3. Visible light communication

In visible light communication, normally the existing underwater VLC systems normally consist of light emitting diodes (LED’s) at the transmitter end and photo diodes at the receiver end. Voltages detected at the receiver are amplified to decode the transmitted data.

> What are the major drawbacks in this system and proposed methods to overcome those ?

When visible light propagates through aqua mediums, they get affected from attenuation and absorption. To overcome these drawbacks and to increase the speed of data transmission, we are developing the existing method from previous phase of the project . We are using,

1. A transmitter made of 100 LEDs

2. A camera as a receiver

As this extends for a turbulent flow we are planning to use machine learning techniques with image processing. This will help to train the receiver to identify LED locations in the transmitter more specifically.

• C. Wang, H.-Y. Yu, and Y.-J. Zhu, “A Long Distance Underwater Visible Light Communication System With Single Photon Avalanche Diode,” IEEE Photonics Journal, vol. 8, no. 5, pp. 1–11, 2016
• M. V. Jamali, A. Chizari, and J. A. Salehi, “Performance Analysis of Multi-Hop Underwater Wireless Optical Communication Systems,” IEEE Photonics Technology Letters, vol. 29, no. 5, pp. 462–465, Jan. 2017.
• https://www.researchgate.net/publication/293825043_Light_Sensing_Robot [accessed Sep 29 2018].