Underwater acoustic communication performance by signal to noise plus interference ratio in BLAC18

In underwater acoustic communications, inter-symbol interference (ISI) caused by multipath propagation of underwater channel degrades communication performance significantly. Various techniques, such as time reversal combining and decision feedback equalization, have been developed to eliminate the influence of the interference. However, few studies have assessed the performance with the signal-to-noise (SNR) of received communication signals. In practical underwater acoustic systems, the channel must be accurately estimated for the channel equalization and the SNR is involved in the accuracy of the channel estimation. The effect of interference is dominant at short distances, but the effect of noise becomes dominant as distance increases. In this study, SNR, signal-to-interference ratio, and signal-to-noise plus interference ratio (SINR) are estimated as a function of the distance, and communication performances are examined. Communication data from BLAC18, conducted in East Sea of Korea in 2018, are used to analyze the communication performances. In the experiment, communication signals with a carrier frequency of 2.5 kHz were transmitted and received at horizontal distances of 30, 60, and 90 km. Data analysis results shows that communication performance is most correlated with SINR. [Work supported by the ADD(UD170022DD).]