Performance analysis of underwater optical wireless communication system under clear oceanic environment

Abstract Underwater wireless communication is the use of wireless carriers, such as radio-frequency waves, acoustic waves, and optical waves, to transmit data in an unguided aquatic environment. This study focuses on underwater optical wireless communication (UOWC), leveraging the high bandwidth of optical waves for enhanced data rates. While orthogonal frequency division multiplexing (OFDM) and space-time block coding (STBC) are well-established in radio frequency (RF) and free-space optical systems, their application in UOWC introduces unique challenges due to underwater attenuation, scattering, and multipath effects. UOWC holds significant potential in military, offshore exploration, environmental monitoring, and disaster response, yet is constrained by severe absorption and scattering in underwater channels. This work examines coding, modulation, and channel characteristics in UOWC systems. It analyzes outage performance in terms of bandwidth, bit error rate (BER), and carrier-to-noise ratio (CNR) to optimize communication links. Power penalties over varying distances are examined, showing increasing degradation with longer transmission ranges. From the analysis it is found that at a short distance of 10 m, power penalties range from approximately 11–16 dB for received optical power levels between 10 −2 and 10 −12 . At 120 m, the power penalty increases to 28–31 dB with corresponding BER values from 10 −2 to 10 −12 . These findings underscore the need for advanced signal processing and adaptive modulation to minimize power loss and enhance UOWC system efficiency in practical scenarios.