The research on acoustic communication anti-doppler shift technology based on FrFFT

摘要

Underwater acoustic communication technology plays an important role in underwater applications, but the sound velocity v0 in underwater acoustic channel is much lower than the propagation velocity c0 in electromagnetic wave in the air. It is assumed that the velocity of the platform is v, i.e. v/v0 v/c0 makes the influence of the velocity of the platform in the underwater acoustic channel on the doppler shift of the receiver far greater than the influence of the electromagnetic wave mobile platform in the air on the receiver channel. In this paper, a joint channel coding and decoding method based on LFM-FrFFT (Linear Frequency Modulation- Fast Fourier Transform) is proposed. The receiver system decodes the communication system by detecting the up-and-down frequency sweep of the LFM. Due to the doppler insensitivity of the LFM signal, the FrFft can effectively detect the LFM signal through the fractional-order domain to solve the Doppler-induced receiver channel mismatch problem.