Performance Analysis of Modulation Techniques for Underwater Wireless Optical Communication Across Diverse Water Conditions

Underwater wireless optical communication (UWOC) holds immense potential for enabling high-speed data transmission in aquatic environments. Traditional radio frequency (RF) technologies face limitations in underwater communication due to signal attenuation and low data rates. The study proposes leveraging light-based communication as an alternative to RF technology for underwater applications. Light, with its faster propagation speed and higher data rates, presents a promising solution for overcoming the challenges of underwater communication. However, the attenuation of light in water, caused by absorption and scattering, poses a significant obstacle to its practical implementation. Using Opti System modeling, the study examines the attenuation properties of four different types of water: turbid water, ocean water, coastal water, and clean seawater. The most effective modulation method is identified by comparing the Bit Error Rate (BER) of four modulation schemes: Phase Shift Keying (PSK), Differential Phase Shift Keying (DPSK), Quadrature Phase Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM). DPSK consistently has the lowest BER of the evaluated modulation schemes, indicating greater performance, particularly over longer distances. QPSK follows with a reasonably low BER over shorter distances, giving it a competitive solution for moderate distance applications. PSK and QAM, on the other hand, exhibit larger BERs; QAM is more sensitive to distance, meaning that signal quality degrades more as distance increases. The research results offer insights on the best modulation techniques that are suitable for effective underwater optical communication.