Underwater Acoustic Communication by a Single-Vector Sensor: Performance Comparison Using Three Different Algorithms

In November, 2014, the underwater acoustic (UWA) communication experiment by a single-vector sensor was conducted in shallow water environment. In this paper, three different algorithms are used to process the experimental data and their performance are compared in terms of equalized output signal to noise ratio (OSNR) and bit error rate (BER). The three algorithms are P-DFE, B-DFE, and T-DFE, respectively. P-DFE uses only the pressure channel of the vector sensor to realize the decision feedback equalizer (DFE). B-DFE linearly combines the pressure channel and velocity channel first and then uses DFE to equalize the combined signal. T-DFE adopts time reversal to combine all the channels of the vector sensor and then is followed by a single-channel DFE to remove residual intersymbol interference (ISI). According to the data processing results, both B-DFE and T-DFE can achieve better performance compared with P-DFE. This paper also finds that the performance of B-DFE depends on the beam pattern of the combined signal while the performance of T-DFE depends on the q function of the combined signal. Which algorithm should be used to process real data, B-DFE or T-DFE, depends on the degree of coherence between different channels of the vector sensor.