Experimental study of Acoustic Communication over Deep-sea Vertical Channel

Underwater acoustic communication (UAC) has been widely used in UUVs navigation control data transmission, deep-seabed resource investigation and underwater acoustic communication networks. Many scholars have carried out more research on acoustic communication technology over underwater horizontal channels, and there are relatively few researches on UAC over deep-sea vertical channels. This paper is devoted to an experimental study of UAC over deep-sea vertical channels between two types of underwater acoustic MODEM which were installed on the tsunami buoy and the sea-bed base, and based on two types of spread-spectrum technique, direct sequence spread spectrum (DSSS) and sweep-spread carrier (S2C), respectively. We analyze two times long-term experimental data recorded in the SD card after MODEM demodulation with 1360m sea-depth and 3870m sea-depth, and concentrate on the deep-sea vertical channel properties such as the time-delay spread, the amplitude of the successive paths and the time-varying multipath structure. The tsunami buoy received packets demonstrate the better BER performance of DSSS than S2C, and it can be explained by the deep-sea vertical channel properties and the derivation of two types of spread-spectrum technique principle.