Modeling and simulation of OFDM based underwater communication system

In this study, an underwater communication model employing Orthogonal Frequency Division Multiplexing (OFDM) has been developed, and the results obtained from this model have been evaluated. Using mathematical formulas related to underwater environment losses and modulation parameters, data was divided into sub-symbols, and the losses in the underwater environment were calculated. The received symbols were reassembled, and performance parameters were analyzed. The model was parameterized, and by altering the parameters, Signal-to-Noise Ratio (SNR), Bit Error Rate (BER), and underwater environment losses were examined. According to the SNR analysis of the proposed model, it was observed that the SNR value, which is 50 dB at a distance of 1000 meters, decreases to 25 dB at 10,000 meters. This finding demonstrates that signal strength decreases logarithmically with distance. In the examination of BER performance, at a transmission power of 150 dB and 50 dB SNR, the BER at a distance of 1000 meters is '0'. However, at 70 dB power over the same distance, BER increases to '0.12'. This indicates that a higher SNR improves performance. In transmission loss analysis, the total loss, which is 35.57 dB at 100 meters, reaches 115 dB at 10,000 meters, revealing that distance plays a significant role in the degradation of signal quality. Depth-wise, the loss, which is 52.79 dB at 100 meters, rises to 62.69 dB at 10,000 meters; however, the impact of depth remains limited compared to distance. In frequency analysis, the loss, which is 52.79 dB at 27 kHz, increases to 192.63 dB at 540 kHz, demonstrating that higher frequencies exacerbate absorption losses. Upon evaluating the results obtained with this proposed communication model, it is evident that frequency and distance have a greater impact on communication performance in non-periodic data transfer compared to other parameters.