OFDM Signals Underwater Experiments and Analysis in East Sea of South Korea

Underwater communications are significantly challenging due to its characteristics. Sound wave has a slow transmission speed of 1500m/sec, and dispersion and refraction occur due to time-varying changes in sea level and geometric forms of the seafloor. Moreover, absorption occurs depending on and material. Multipath, delay spread, the Doppler effects also deteriorate the underwater communications. OFDM underwater transmission experiments was conducted from June 22nd to 24th in 2023 near the East Sea of Korea. Four different frames are designed for experiments and this paper analyses the experiment results using BER and SNR. The analysis shows the best performance at 13.5dB SNR using one frame option for the OFDM signal transmissions and receptions.