| dc.description.abstract | Underwater communication is a crucial aspect of maritime and marine technology development, finding applications particularly in emergency scenarios such as aircraft and ship accidents in open waters. Effective and rapid communication is essential among rescue teams operating underwater. The high cost and impracticality of using optical fibers for underwater communication pose significant challenges. Consequently, underwater wireless communication becomes essential, albeit facing its own challenges, including issues related to electromagnetic wave frequencies and limitations in data transmission speed.
Underwater Visible Light Communication (UVLC) technology, which utilizes visible light as a carrier, emerges as a solution for current underwater communication discussions. This research involves the design and construction of a UVLC prototype comprising LED and laser transmitters capable of communicating text and voice. To assess its performance under various underwater conditions such as light pollution, water pollution, and water salinity, observations were conducted at distances ranging from 0.5 m to 3 m.
The research findings indicate that the UVLC LED and laser prototype successfully transmitted text using on-off-keying modulation at a transfer speed of up to 400 bps, enabling the transmission of 1000 characters in approximately 20 seconds. Moreover, the prototype demonstrated real-time voice transmission capabilities underwater. The best performance, based on measurements, occurred in clear water conditions without external light, where UVLC LED and laser communicated text with a Bit Error Rate (BER) of 0 up to a distance of 3 m, and average sound intensity values of 79.6 and 82.0 dB for UVLC LED and laser, respectively. The worst text transmission performance occurred in conditions with significant external light, resulting in a BER of 1.20 x 10-2 at a distance of 1 m for UVLC LED. In contrast, voice transmission under murky water conditions was poorest for UVLC laser, with an average sound intensity of 58.1 dB. Considering the transmitter type, UVLC laser performed best with an average sound intensity in each measurement condition of 75.72 dB, while UVLC LED had an average of 73.22 dB. Furthermore, estimated path loss values for a distance of 100 m in clear and murky seawater were 138 dB and 1015 dB for UVLC laser, and 151 dB and 1028 dB for UVLC LED, respectively | en_US |
