Effects of Modulation Scheme on Experimental Setup of RGB LEDs Based Underwater Optical Communication

Underwater LED based Optical Communication has immense applications in the marine, autonomous underwater vehicle drivers and military fields. Compared with traditional underwater acoustic communication LED based optical communication offers secure, very high data rates (in ~ Gbps), and short wavelength which makes the antenna size of transmitter and receiver relatively small. In this paper an experimental setup of underwater LED (using Red, Green and Blue color) based optical communication in a 39 × 8 × 12 inches tank is designed to achieve data rates of 2 Mbps at a distance of 1 m. Furthermore, the performance comparison of free space and underwater optical link using ASK, FSK and PSK is made along with NRZ line encoding scheme. The results are presented and discussed in terms of eye diagrams and bit error rates. The experimental results reveal that the blue color LED has best received signal strength in comparison to the green and red LEDs in underwater medium. All three LEDs achieve a bit error rate of around 10−5 with blue LED achieving highest SNR of 22.5 dB.