수중 페이딩 변화 특성이 수중 통신성능에 미치는 영향

Abstract

Underwater acoustic communication systems using acoustic wave is required modulation methods to enable high speed information transmission and to overcome environment of time-space variation. In the real sea, Doppler spread by surface fluctuation, multipath and movement of a transmitter-receiver by surface and bottom of the sea are affect on communication performance, In the real sea. In this study, underwater acoustic communication performance are evaluated modulation methods, BFSK(Binary Frequency Shift Keying), BPSK(Binary Phase Shift Keying), and QPSK(Quadrature Phase Shift Keying) according to fading variation by Doppler spread. In the experiment, fading characteristic of channel is analysed by using AWGN(Additive White Gaussian Noise) for dynamic and static statement of a receiver. The performance of three modulation methods is evaluated to dynamic and static statement of a receiver. And strong method for fading variation by a moving receiver is evaluated through the experiment. As a result, QPSK method is confirmed very excellent for high-speed and lower error rate compared with other methods in underwater static channel. Also, performance is improved when FSK method is applied to system than PSK method in the dynamic channel.